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<record><TEI><teiHeader><fileDesc><titleStmt><title xml:lang="en">A standard calculation methodology for human doubly labeled water studies</title><author><name sortKey="Speakman, John R" sort="Speakman, John R" uniqKey="Speakman J" first="John R." last="Speakman">John R. Speakman</name><affiliation><nlm:aff id="aff1">Center for Energy Metabolism and Reproduction, Shenzhen Institutes of Advanced Technology, Chinese Academy of Sciences, Shenzhen, China</nlm:aff></affiliation><affiliation><nlm:aff id="aff2">Institute of Biological and Environmental Sciences, University of Aberdeen, Aberdeen, UK</nlm:aff></affiliation><affiliation><nlm:aff id="aff3">State Key Laboratory of Molecular Developmental Biology, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing, China</nlm:aff></affiliation><affiliation><nlm:aff id="aff4">CAS Center of Excellence in Animal Evolution and Genetics, Kunming, China</nlm:aff></affiliation></author><author><name sortKey="Yamada, Yosuke" sort="Yamada, Yosuke" uniqKey="Yamada Y" first="Yosuke" last="Yamada">Yosuke Yamada</name><affiliation><nlm:aff id="aff5">National Institute of Health and Nutrition, National Institutes of Biomedical Innovation, Health and Nutrition, Tokyo, Japan</nlm:aff></affiliation><affiliation><nlm:aff id="aff6">Institute for Active Health, Kyoto University of Advanced Science, Kyoto, Japan</nlm:aff></affiliation></author><author><name sortKey="Sagayama, Hiroyuki" sort="Sagayama, Hiroyuki" uniqKey="Sagayama H" first="Hiroyuki" last="Sagayama">Hiroyuki Sagayama</name><affiliation><nlm:aff id="aff7">Faculty of Health and Sport Sciences, University of Tsukuba, Ibaraki, Japan</nlm:aff></affiliation></author><author><name sortKey="Berman, Elena S F" sort="Berman, Elena S F" uniqKey="Berman E" first="Elena S. F." last="Berman">Elena S. F. Berman</name><affiliation><nlm:aff id="aff8">Berman Scientific Consulting, Mountain View, CA, USA</nlm:aff></affiliation></author><author><name sortKey="Ainslie, Philip N" sort="Ainslie, Philip N" uniqKey="Ainslie P" first="Philip N." last="Ainslie">Philip N. Ainslie</name><affiliation><nlm:aff id="aff9">Research Institute for Sport and Exercise Sciences, Liverpool John Moores University, Liverpool, UK</nlm:aff></affiliation></author><author><name sortKey="Andersen, Lene F" sort="Andersen, Lene F" uniqKey="Andersen L" first="Lene F." last="Andersen">Lene F. Andersen</name><affiliation><nlm:aff id="aff10">Department of Nutrition, Institute of Basic Medical Sciences, University of Oslo, 0317 Oslo, Norway</nlm:aff></affiliation></author><author><name sortKey="Anderson, Liam J" sort="Anderson, Liam J" uniqKey="Anderson L" first="Liam J." last="Anderson">Liam J. Anderson</name><affiliation><nlm:aff id="aff9">Research Institute for Sport and Exercise Sciences, Liverpool John Moores University, Liverpool, UK</nlm:aff></affiliation><affiliation><nlm:aff id="aff11">Crewe Alexandra Football Club, Crewe, UK</nlm:aff></affiliation></author><author><name sortKey="Arab, Lenore" sort="Arab, Lenore" uniqKey="Arab L" first="Lenore" last="Arab">Lenore Arab</name><affiliation><nlm:aff id="aff12">David Geffen School of Medicine, University of California, Los Angeles, Los Angeles, CA, USA</nlm:aff></affiliation></author><author><name sortKey="Baddou, Issaad" sort="Baddou, Issaad" uniqKey="Baddou I" first="Issaad" last="Baddou">Issaad Baddou</name><affiliation><nlm:aff id="aff13">Unité Mixte de Recherche en Nutrition et Alimentation, CNESTEN- Université Ibn Tofail URAC39, Regional Designated Center of Nutrition Associated with AFRA/IAEA, Rabat, Morocco</nlm:aff></affiliation></author><author><name sortKey="Bedu Addo, Kweku" sort="Bedu Addo, Kweku" uniqKey="Bedu Addo K" first="Kweku" last="Bedu-Addo">Kweku Bedu-Addo</name><affiliation><nlm:aff id="aff14">Department of Physiology, Kwame Nkrumah University of Science and Technology, Kumasi, Ghana</nlm:aff></affiliation></author><author><name sortKey="Blaak, Ellen E" sort="Blaak, Ellen E" uniqKey="Blaak E" first="Ellen E." last="Blaak">Ellen E. Blaak</name><affiliation><nlm:aff id="aff15">Maastricht University, Maastricht, the Netherlands</nlm:aff></affiliation></author><author><name sortKey="Blanc, Stephane" sort="Blanc, Stephane" uniqKey="Blanc S" first="Stephane" last="Blanc">Stephane Blanc</name><affiliation><nlm:aff id="aff16">Nutritional Sciences, University of Wisconsin, Madison, WI, USA</nlm:aff></affiliation><affiliation><nlm:aff id="aff17">Institut Pluridisciplinaire Hubert Curien, CNRS Université de Strasbourg, UMR7178, Strasbourg, France</nlm:aff></affiliation></author><author><name sortKey="Bonomi, Alberto G" sort="Bonomi, Alberto G" uniqKey="Bonomi A" first="Alberto G." last="Bonomi">Alberto G. Bonomi</name><affiliation><nlm:aff id="aff18">Phillips Research, Eindhoven, the Netherlands</nlm:aff></affiliation></author><author><name sortKey="Bouten, Carlijn V C" sort="Bouten, Carlijn V C" uniqKey="Bouten C" first="Carlijn V. C." last="Bouten">Carlijn V. C. Bouten</name><affiliation><nlm:aff id="aff19">Department of Biomedical Engineering and Institute for Complex Molecular Systems, Eindhoven University of Technology, Eindhoven, the Netherlands</nlm:aff></affiliation></author><author><name sortKey="Bovet, Pascal" sort="Bovet, Pascal" uniqKey="Bovet P" first="Pascal" last="Bovet">Pascal Bovet</name><affiliation><nlm:aff id="aff20">Institute of Social and Preventive Medicine, Lausanne University Hospital, Lausanne, Switzerland</nlm:aff></affiliation></author><author><name sortKey="Buchowski, Maciej S" sort="Buchowski, Maciej S" uniqKey="Buchowski M" first="Maciej S." last="Buchowski">Maciej S. Buchowski</name><affiliation><nlm:aff id="aff21">Division of Gastroenterology, Hepatology and Nutrition, Department of Medicine, Vanderbilt University, Nashville, TN, USA</nlm:aff></affiliation></author><author><name sortKey="Butte, Nancy F" sort="Butte, Nancy F" uniqKey="Butte N" first="Nancy F." last="Butte">Nancy F. Butte</name><affiliation><nlm:aff id="aff22">Department of Pediatrics, Baylor College of Medicine, USDA/ARS Children’s Nutrition Research Center, Houston, TX, USA</nlm:aff></affiliation></author><author><name sortKey="Camps, Stefan G J A" sort="Camps, Stefan G J A" uniqKey="Camps S" first="Stefan G. J. A." last="Camps">Stefan G. J. A. Camps</name><affiliation><nlm:aff id="aff15">Maastricht University, Maastricht, the Netherlands</nlm:aff></affiliation></author><author><name sortKey="Close, Graeme L" sort="Close, Graeme L" uniqKey="Close G" first="Graeme L." last="Close">Graeme L. Close</name><affiliation><nlm:aff id="aff9">Research Institute for Sport and Exercise Sciences, Liverpool John Moores University, Liverpool, UK</nlm:aff></affiliation></author><author><name sortKey="Cooper, Jamie A" sort="Cooper, Jamie A" uniqKey="Cooper J" first="Jamie A." last="Cooper">Jamie A. Cooper</name><affiliation><nlm:aff id="aff16">Nutritional Sciences, University of Wisconsin, Madison, WI, USA</nlm:aff></affiliation></author><author><name sortKey="Creasy, Seth A" sort="Creasy, Seth A" uniqKey="Creasy S" first="Seth A." last="Creasy">Seth A. Creasy</name><affiliation><nlm:aff id="aff23">Division of Endocrinology, Metabolism and Diabetes, University of Colorado Anschulz Medical Campus, Aurora, CO, USA</nlm:aff></affiliation></author><author><name sortKey="Das, Sai Krupa" sort="Das, Sai Krupa" uniqKey="Das S" first="Sai Krupa" last="Das">Sai Krupa Das</name><affiliation><nlm:aff id="aff24">Friedman School of Nutrition Science and Policy, Tufts University, 150 Harrison Avenue, Boston, MA, USA</nlm:aff></affiliation></author><author><name sortKey="Cooper, Richard" sort="Cooper, Richard" uniqKey="Cooper R" first="Richard" last="Cooper">Richard Cooper</name><affiliation><nlm:aff id="aff25">Department of Public Health Sciences, Parkinson School of Health Sciences and Public Health, Loyola University, Maywood, IL, USA</nlm:aff></affiliation></author><author><name sortKey="Dugas, Lara R" sort="Dugas, Lara R" uniqKey="Dugas L" first="Lara R." last="Dugas">Lara R. Dugas</name><affiliation><nlm:aff id="aff25">Department of Public Health Sciences, Parkinson School of Health Sciences and Public Health, Loyola University, Maywood, IL, USA</nlm:aff></affiliation></author><author><name sortKey="Ebbeling, Cara B" sort="Ebbeling, Cara B" uniqKey="Ebbeling C" first="Cara B." last="Ebbeling">Cara B. Ebbeling</name><affiliation><nlm:aff id="aff26">Boston Children’s Hospital, Boston, MA, USA</nlm:aff></affiliation></author><author><name sortKey="Ekelund, Ulf" sort="Ekelund, Ulf" uniqKey="Ekelund U" first="Ulf" last="Ekelund">Ulf Ekelund</name><affiliation><nlm:aff id="aff27">Department of Sport Medicine, Norwegian School of Sport Sciences, Oslo, Norway</nlm:aff></affiliation></author><author><name sortKey="Entringer, Sonja" sort="Entringer, Sonja" uniqKey="Entringer S" first="Sonja" last="Entringer">Sonja Entringer</name><affiliation><nlm:aff id="aff28">Charité – Universitätsmedizin Berlin, corporate member of Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health (BIH), Institute of Medical Psychology, Berlin, Germany</nlm:aff></affiliation><affiliation><nlm:aff id="aff29">University of California, Irvine, Irvine, CA, USA</nlm:aff></affiliation></author><author><name sortKey="Forrester, Terrence" sort="Forrester, Terrence" uniqKey="Forrester T" first="Terrence" last="Forrester">Terrence Forrester</name><affiliation><nlm:aff id="aff30">Solutions for Developing Countries, University of the West Indies, Mona, Kingston, Jamaica</nlm:aff></affiliation></author><author><name sortKey="Fudge, Barry W" sort="Fudge, Barry W" uniqKey="Fudge B" first="Barry W." last="Fudge">Barry W. Fudge</name><affiliation><nlm:aff id="aff31">University of Glasgow, Glasgow, UK</nlm:aff></affiliation></author><author><name sortKey="Goris, Annelies H" sort="Goris, Annelies H" uniqKey="Goris A" first="Annelies H." last="Goris">Annelies H. Goris</name><affiliation><nlm:aff id="aff15">Maastricht University, Maastricht, the Netherlands</nlm:aff></affiliation></author><author><name sortKey="Gurven, Michael" sort="Gurven, Michael" uniqKey="Gurven M" first="Michael" last="Gurven">Michael Gurven</name><affiliation><nlm:aff id="aff32">Department of Anthropology, University of California, Santa Barbara, Santa Barbara, CA, USA</nlm:aff></affiliation></author><author><name sortKey="Hambly, Catherine" sort="Hambly, Catherine" uniqKey="Hambly C" first="Catherine" last="Hambly">Catherine Hambly</name><affiliation><nlm:aff id="aff2">Institute of Biological and Environmental Sciences, University of Aberdeen, Aberdeen, UK</nlm:aff></affiliation></author><author><name sortKey="El Hamdouchi, Asmaa" sort="El Hamdouchi, Asmaa" uniqKey="El Hamdouchi A" first="Asmaa" last="El Hamdouchi">Asmaa El Hamdouchi</name><affiliation><nlm:aff id="aff13">Unité Mixte de Recherche en Nutrition et Alimentation, CNESTEN- Université Ibn Tofail URAC39, Regional Designated Center of Nutrition Associated with AFRA/IAEA, Rabat, Morocco</nlm:aff></affiliation></author><author><name sortKey="Hoos, Marije B" sort="Hoos, Marije B" uniqKey="Hoos M" first="Marije B." last="Hoos">Marije B. Hoos</name><affiliation><nlm:aff id="aff15">Maastricht University, Maastricht, the Netherlands</nlm:aff></affiliation></author><author><name sortKey="Hu, Sumei" sort="Hu, Sumei" uniqKey="Hu S" first="Sumei" last="Hu">Sumei Hu</name><affiliation><nlm:aff id="aff3">State Key Laboratory of Molecular Developmental Biology, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing, China</nlm:aff></affiliation></author><author><name sortKey="Joonas, Noorjehan" sort="Joonas, Noorjehan" uniqKey="Joonas N" first="Noorjehan" last="Joonas">Noorjehan Joonas</name><affiliation><nlm:aff id="aff33">Central Health Laboratory, Ministry of Health and Wellness, Port Louis, Mauritius</nlm:aff></affiliation></author><author><name sortKey="Joosen, Annemiek M" sort="Joosen, Annemiek M" uniqKey="Joosen A" first="Annemiek M." last="Joosen">Annemiek M. Joosen</name><affiliation><nlm:aff id="aff15">Maastricht University, Maastricht, the Netherlands</nlm:aff></affiliation></author><author><name sortKey="Katzmarzyk, Peter" sort="Katzmarzyk, Peter" uniqKey="Katzmarzyk P" first="Peter" last="Katzmarzyk">Peter Katzmarzyk</name><affiliation><nlm:aff id="aff34">Pennington Biomedical Research Center, Baton Rouge, LA, USA</nlm:aff></affiliation></author><author><name sortKey="Kempen, Kitty P" sort="Kempen, Kitty P" uniqKey="Kempen K" first="Kitty P." last="Kempen">Kitty P. Kempen</name><affiliation><nlm:aff id="aff15">Maastricht University, Maastricht, the Netherlands</nlm:aff></affiliation></author><author><name sortKey="Kimura, Misaka" sort="Kimura, Misaka" uniqKey="Kimura M" first="Misaka" last="Kimura">Misaka Kimura</name><affiliation><nlm:aff id="aff6">Institute for Active Health, Kyoto University of Advanced Science, Kyoto, Japan</nlm:aff></affiliation></author><author><name sortKey="Kraus, William E" sort="Kraus, William E" uniqKey="Kraus W" first="William E." last="Kraus">William E. Kraus</name><affiliation><nlm:aff id="aff35">Department of Medicine, Duke University, Durham, NC, USA</nlm:aff></affiliation></author><author><name sortKey="Kushner, Robert F" sort="Kushner, Robert F" uniqKey="Kushner R" first="Robert F." last="Kushner">Robert F. Kushner</name><affiliation><nlm:aff id="aff36">Northwestern University, Chicago, IL, USA</nlm:aff></affiliation></author><author><name sortKey="Lambert, Estelle V" sort="Lambert, Estelle V" uniqKey="Lambert E" first="Estelle V." last="Lambert">Estelle V. Lambert</name><affiliation><nlm:aff id="aff37">Research Unit for Exercise Science and Sports Medicine, University of Cape Town, Cape Town, South Africa</nlm:aff></affiliation></author><author><name sortKey="Leonard, William R" sort="Leonard, William R" uniqKey="Leonard W" first="William R." last="Leonard">William R. Leonard</name><affiliation><nlm:aff id="aff38">Department of Anthropology, Northwestern University, Evanston, IL, USA</nlm:aff></affiliation></author><author><name sortKey="Lessan, Nader" sort="Lessan, Nader" uniqKey="Lessan N" first="Nader" last="Lessan">Nader Lessan</name><affiliation><nlm:aff id="aff39">Imperial College London Diabetes Centre, Imperial College London, London, UK</nlm:aff></affiliation></author><author><name sortKey="Ludwig, David S" sort="Ludwig, David S" uniqKey="Ludwig D" first="David S." last="Ludwig">David S. Ludwig</name><affiliation><nlm:aff id="aff26">Boston Children’s Hospital, Boston, MA, USA</nlm:aff></affiliation></author><author><name sortKey="Martin, Corby K" sort="Martin, Corby K" uniqKey="Martin C" first="Corby K." last="Martin">Corby K. Martin</name><affiliation><nlm:aff id="aff34">Pennington Biomedical Research Center, Baton Rouge, LA, USA</nlm:aff></affiliation></author><author><name sortKey="Medin, Anine C" sort="Medin, Anine C" uniqKey="Medin A" first="Anine C." last="Medin">Anine C. Medin</name><affiliation><nlm:aff id="aff10">Department of Nutrition, Institute of Basic Medical Sciences, University of Oslo, 0317 Oslo, Norway</nlm:aff></affiliation><affiliation><nlm:aff id="aff40">Department of Nutrition and Public Health, Faculty of Health and Sport Sciences, University of Agder, 4630 Kristiansand, Norway</nlm:aff></affiliation></author><author><name sortKey="Meijer, Erwin P" sort="Meijer, Erwin P" uniqKey="Meijer E" first="Erwin P." last="Meijer">Erwin P. Meijer</name><affiliation><nlm:aff id="aff15">Maastricht University, Maastricht, the Netherlands</nlm:aff></affiliation></author><author><name sortKey="Morehen, James C" sort="Morehen, James C" uniqKey="Morehen J" first="James C." last="Morehen">James C. Morehen</name><affiliation><nlm:aff id="aff9">Research Institute for Sport and Exercise Sciences, Liverpool John Moores University, Liverpool, UK</nlm:aff></affiliation><affiliation><nlm:aff id="aff41">The FA Group, Burton-Upon-Trent, Staffordshire, UK</nlm:aff></affiliation></author><author><name sortKey="Morton, James P" sort="Morton, James P" uniqKey="Morton J" first="James P." last="Morton">James P. Morton</name><affiliation><nlm:aff id="aff9">Research Institute for Sport and Exercise Sciences, Liverpool John Moores University, Liverpool, UK</nlm:aff></affiliation></author><author><name sortKey="Neuhouser, Marian L" sort="Neuhouser, Marian L" uniqKey="Neuhouser M" first="Marian L." last="Neuhouser">Marian L. Neuhouser</name><affiliation><nlm:aff id="aff42">Division of Public Health Sciences, Fred Hutchinson Cancer Research Center and School of Public Health, University of Washington, Seattle, WA, USA</nlm:aff></affiliation></author><author><name sortKey="Nicklas, Theresa A" sort="Nicklas, Theresa A" uniqKey="Nicklas T" first="Theresa A." last="Nicklas">Theresa A. Nicklas</name><affiliation><nlm:aff id="aff22">Department of Pediatrics, Baylor College of Medicine, USDA/ARS Children’s Nutrition Research Center, Houston, TX, USA</nlm:aff></affiliation></author><author><name sortKey="Ojiambo, Robert M" sort="Ojiambo, Robert M" uniqKey="Ojiambo R" first="Robert M." last="Ojiambo">Robert M. Ojiambo</name><affiliation><nlm:aff id="aff43">Moi University, Eldoret, Kenya</nlm:aff></affiliation><affiliation><nlm:aff id="aff44">University of Global Health Equity, Kigali, Rwanda</nlm:aff></affiliation></author><author><name sortKey="Pietil Inen, Kirsi H" sort="Pietil Inen, Kirsi H" uniqKey="Pietil Inen K" first="Kirsi H." last="Pietil Inen">Kirsi H. Pietil Inen</name><affiliation><nlm:aff id="aff45">Helsinki University Central Hospital, Helsinki, Finland</nlm:aff></affiliation></author><author><name sortKey="Pitsiladis, Yannis P" sort="Pitsiladis, Yannis P" uniqKey="Pitsiladis Y" first="Yannis P." last="Pitsiladis">Yannis P. Pitsiladis</name><affiliation><nlm:aff id="aff46">University of Brighton, Eastbourne, UK</nlm:aff></affiliation></author><author><name sortKey="Plange Rhule, Jacob" sort="Plange Rhule, Jacob" uniqKey="Plange Rhule J" first="Jacob" last="Plange-Rhule">Jacob Plange-Rhule</name><affiliation><nlm:aff id="aff47">Department of Physiology, Kwame Nkrumah University of Science and Technology, Kumasi, Ghana</nlm:aff></affiliation></author><author><name sortKey="Plasqui, Guy" sort="Plasqui, Guy" uniqKey="Plasqui G" first="Guy" last="Plasqui">Guy Plasqui</name><affiliation><nlm:aff id="aff48">Department of Nutrition and Movement Sciences, Maastricht University, Maastricht, the Netherlands</nlm:aff></affiliation></author><author><name sortKey="Prentice, Ross L" sort="Prentice, Ross L" uniqKey="Prentice R" first="Ross L." last="Prentice">Ross L. Prentice</name><affiliation><nlm:aff id="aff42">Division of Public Health Sciences, Fred Hutchinson Cancer Research Center and School of Public Health, University of Washington, Seattle, WA, USA</nlm:aff></affiliation></author><author><name sortKey="Rabinovich, Roberto A" sort="Rabinovich, Roberto A" uniqKey="Rabinovich R" first="Roberto A." last="Rabinovich">Roberto A. Rabinovich</name><affiliation><nlm:aff id="aff49">University of Edinburgh, Edinburgh, UK</nlm:aff></affiliation></author><author><name sortKey="Racette, Susan B" sort="Racette, Susan B" uniqKey="Racette S" first="Susan B." last="Racette">Susan B. Racette</name><affiliation><nlm:aff id="aff24">Friedman School of Nutrition Science and Policy, Tufts University, 150 Harrison Avenue, Boston, MA, USA</nlm:aff></affiliation></author><author><name sortKey="Raichlen, David A" sort="Raichlen, David A" uniqKey="Raichlen D" first="David A." last="Raichlen">David A. Raichlen</name><affiliation><nlm:aff id="aff50">Biological Sciences and Anthropology, University of Southern California, Los Angeles, CA, USA</nlm:aff></affiliation></author><author><name sortKey="Ravussin, Eric" sort="Ravussin, Eric" uniqKey="Ravussin E" first="Eric" last="Ravussin">Eric Ravussin</name><affiliation><nlm:aff id="aff34">Pennington Biomedical Research Center, Baton Rouge, LA, USA</nlm:aff></affiliation></author><author><name sortKey="Reynolds, Rebecca M" sort="Reynolds, Rebecca M" uniqKey="Reynolds R" first="Rebecca M." last="Reynolds">Rebecca M. Reynolds</name><affiliation><nlm:aff id="aff51">Centre for Cardiovascular Sciences, Queen’s Medical Research Institute, University of Edinburgh, Edinburgh, UK</nlm:aff></affiliation></author><author><name sortKey="Roberts, Susan B" sort="Roberts, Susan B" uniqKey="Roberts S" first="Susan B." last="Roberts">Susan B. Roberts</name><affiliation><nlm:aff id="aff24">Friedman School of Nutrition Science and Policy, Tufts University, 150 Harrison Avenue, Boston, MA, USA</nlm:aff></affiliation></author><author><name sortKey="Schuit, Albertine J" sort="Schuit, Albertine J" uniqKey="Schuit A" first="Albertine J." last="Schuit">Albertine J. Schuit</name><affiliation><nlm:aff id="aff52">University of Tilburg, Tilburg, the Netherlands</nlm:aff></affiliation></author><author><name sortKey="Sjodin, Anders M" sort="Sjodin, Anders M" uniqKey="Sjodin A" first="Anders M." last="Sjödin">Anders M. Sjödin</name><affiliation><nlm:aff id="aff53">Department of Nutrition, Exercise and Sports, Copenhagen University, Copenhagen, Denmark</nlm:aff></affiliation></author><author><name sortKey="Stice, Eric" sort="Stice, Eric" uniqKey="Stice E" first="Eric" last="Stice">Eric Stice</name><affiliation><nlm:aff id="aff54">Stanford University, Stanford, CA, USA</nlm:aff></affiliation></author><author><name sortKey="Urlacher, Samuel S" sort="Urlacher, Samuel S" uniqKey="Urlacher S" first="Samuel S." last="Urlacher">Samuel S. Urlacher</name><affiliation><nlm:aff id="aff55">Department of Anthropology, Baylor University, Waco, TX, USA</nlm:aff></affiliation></author><author><name sortKey="Valenti, Giulio" sort="Valenti, Giulio" uniqKey="Valenti G" first="Giulio" last="Valenti">Giulio Valenti</name><affiliation><nlm:aff id="aff15">Maastricht University, Maastricht, the Netherlands</nlm:aff></affiliation></author><author><name sortKey="Van Etten, Ludo M" sort="Van Etten, Ludo M" uniqKey="Van Etten L" first="Ludo M." last="Van Etten">Ludo M. Van Etten</name><affiliation><nlm:aff id="aff15">Maastricht University, Maastricht, the Netherlands</nlm:aff></affiliation></author><author><name sortKey="Van Mil, Edgar A" sort="Van Mil, Edgar A" uniqKey="Van Mil E" first="Edgar A." last="Van Mil">Edgar A. Van Mil</name><affiliation><nlm:aff id="aff56">Maastricht and Lifestyle Medicine Center for Children, Jeroen Bosch Hospital’s-Hertogenbosch, Maastricht University, Maastricht, the Netherlands</nlm:aff></affiliation></author><author><name sortKey="Wells, Jonathan C K" sort="Wells, Jonathan C K" uniqKey="Wells J" first="Jonathan C. K." last="Wells">Jonathan C. K. Wells</name><affiliation><nlm:aff id="aff57">Population, Policy and Practice Research and Teaching Department, UCL Great Ormond Street Institute of Child Health, London, UK</nlm:aff></affiliation></author><author><name sortKey="Wilson, George" sort="Wilson, George" uniqKey="Wilson G" first="George" last="Wilson">George Wilson</name><affiliation><nlm:aff id="aff9">Research Institute for Sport and Exercise Sciences, Liverpool John Moores University, Liverpool, UK</nlm:aff></affiliation></author><author><name sortKey="Wood, Brian M" sort="Wood, Brian M" uniqKey="Wood B" first="Brian M." last="Wood">Brian M. Wood</name><affiliation><nlm:aff id="aff58">University of California, Los Angeles, Los Angeles, CA, USA</nlm:aff></affiliation><affiliation><nlm:aff id="aff59">Department of Human Behavior, Ecology, and Culture, Max Planck Institute for Evolutionary Anthropology, Leipzig, Germany</nlm:aff></affiliation></author><author><name sortKey="Yanovski, Jack" sort="Yanovski, Jack" uniqKey="Yanovski J" first="Jack" last="Yanovski">Jack Yanovski</name><affiliation><nlm:aff id="aff60">Growth and Obesity, Division of Intramural Research, NIH, Bethesda, MD, USA</nlm:aff></affiliation></author><author><name sortKey="Yoshida, Tsukasa" sort="Yoshida, Tsukasa" uniqKey="Yoshida T" first="Tsukasa" last="Yoshida">Tsukasa Yoshida</name><affiliation><nlm:aff id="aff5">National Institute of Health and Nutrition, National Institutes of Biomedical Innovation, Health and Nutrition, Tokyo, Japan</nlm:aff></affiliation></author><author><name sortKey="Zhang, Xueying" sort="Zhang, Xueying" uniqKey="Zhang X" first="Xueying" last="Zhang">Xueying Zhang</name><affiliation><nlm:aff id="aff1">Center for Energy Metabolism and Reproduction, Shenzhen Institutes of Advanced Technology, Chinese Academy of Sciences, Shenzhen, China</nlm:aff></affiliation><affiliation><nlm:aff id="aff2">Institute of Biological and Environmental Sciences, University of Aberdeen, Aberdeen, UK</nlm:aff></affiliation></author><author><name sortKey="Murphy Alford, Alexia J" sort="Murphy Alford, Alexia J" uniqKey="Murphy Alford A" first="Alexia J." last="Murphy-Alford">Alexia J. Murphy-Alford</name><affiliation><nlm:aff id="aff61">Nutritional and Health Related Environmental Studies Section, Division of Human Health, International Atomic Energy Agency, Vienna, Austria</nlm:aff></affiliation></author><author><name sortKey="Loechl, Cornelia U" sort="Loechl, Cornelia U" uniqKey="Loechl C" first="Cornelia U." last="Loechl">Cornelia U. Loechl</name><affiliation><nlm:aff id="aff61">Nutritional and Health Related Environmental Studies Section, Division of Human Health, International Atomic Energy Agency, Vienna, Austria</nlm:aff></affiliation></author><author><name sortKey="Melanson, Edward L" sort="Melanson, Edward L" uniqKey="Melanson E" first="Edward L." last="Melanson">Edward L. Melanson</name><affiliation><nlm:aff id="aff23">Division of Endocrinology, Metabolism and Diabetes, University of Colorado Anschulz Medical Campus, Aurora, CO, USA</nlm:aff></affiliation><affiliation><nlm:aff id="aff62">Eastern Colorado VA Geriatric Research, Education and Clinical Center, Aurora, CO, USA</nlm:aff></affiliation><affiliation><nlm:aff id="aff63">Division of Geriatrics, University of Colorado Anschutz Medical Campus, Aurora, CO, USA</nlm:aff></affiliation></author><author><name sortKey="Luke, Amy H" sort="Luke, Amy H" uniqKey="Luke A" first="Amy H." last="Luke">Amy H. Luke</name><affiliation><nlm:aff id="aff64">Division of Epidemiology, Department of Public Health Sciences, Loyola University School of Medicine, Maywood, IL, USA</nlm:aff></affiliation></author><author><name sortKey="Pontzer, Herman" sort="Pontzer, Herman" uniqKey="Pontzer H" first="Herman" last="Pontzer">Herman Pontzer</name><affiliation><nlm:aff id="aff65">Evolutionary Anthropology, Duke University, Durham, NC, USA</nlm:aff></affiliation><affiliation><nlm:aff id="aff66">Duke Global Health Institute, Duke University, Durham, NC, USA</nlm:aff></affiliation></author><author><name sortKey="Rood, Jennifer" sort="Rood, Jennifer" uniqKey="Rood J" first="Jennifer" last="Rood">Jennifer Rood</name><affiliation><nlm:aff id="aff34">Pennington Biomedical Research Center, Baton Rouge, LA, USA</nlm:aff></affiliation></author><author><name sortKey="Schoeller, Dale A" sort="Schoeller, Dale A" uniqKey="Schoeller D" first="Dale A." last="Schoeller">Dale A. Schoeller</name><affiliation><nlm:aff id="aff67">Biotech Center and Nutritional Sciences, University of Wisconsin, Madison, WI, USA</nlm:aff></affiliation></author><author><name sortKey="Westerterp, Klaas R" sort="Westerterp, Klaas R" uniqKey="Westerterp K" first="Klaas R." last="Westerterp">Klaas R. Westerterp</name><affiliation><nlm:aff id="aff68">School of Nutrition and Translational Research in Metabolism, University of Maastricht, Maastricht, the Netherlands</nlm:aff></affiliation></author><author><name sortKey="Wong, William W" sort="Wong, William W" uniqKey="Wong W" first="William W." last="Wong">William W. Wong</name><affiliation><nlm:aff id="aff22">Department of Pediatrics, Baylor College of Medicine, USDA/ARS Children’s Nutrition Research Center, Houston, TX, USA</nlm:aff></affiliation></author></titleStmt><publicationStmt><idno type="wicri:source">PMC</idno><idno type="pmid">33665639</idno><idno type="pmc">7897799</idno><idno type="url">http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7897799</idno><idno type="RBID">PMC:7897799</idno><idno type="doi">10.1016/j.xcrm.2021.100203</idno><date when="2021">2021</date><idno type="wicri:Area/Pmc/Corpus">000173</idno><idno type="wicri:explorRef" wicri:stream="Pmc" wicri:step="Corpus" wicri:corpus="PMC">000173</idno></publicationStmt><sourceDesc><biblStruct><analytic><title xml:lang="en" level="a" type="main">A standard calculation methodology for human doubly labeled water studies</title><author><name sortKey="Speakman, John R" sort="Speakman, John R" uniqKey="Speakman J" first="John R." last="Speakman">John R. Speakman</name><affiliation><nlm:aff id="aff1">Center for Energy Metabolism and Reproduction, Shenzhen Institutes of Advanced Technology, Chinese Academy of Sciences, Shenzhen, China</nlm:aff></affiliation><affiliation><nlm:aff id="aff2">Institute of Biological and Environmental Sciences, University of Aberdeen, Aberdeen, UK</nlm:aff></affiliation><affiliation><nlm:aff id="aff3">State Key Laboratory of Molecular Developmental Biology, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing, China</nlm:aff></affiliation><affiliation><nlm:aff id="aff4">CAS Center of Excellence in Animal Evolution and Genetics, Kunming, China</nlm:aff></affiliation></author><author><name sortKey="Yamada, Yosuke" sort="Yamada, Yosuke" uniqKey="Yamada Y" first="Yosuke" last="Yamada">Yosuke Yamada</name><affiliation><nlm:aff id="aff5">National Institute of Health and Nutrition, National Institutes of Biomedical Innovation, Health and Nutrition, Tokyo, Japan</nlm:aff></affiliation><affiliation><nlm:aff id="aff6">Institute for Active Health, Kyoto University of Advanced Science, Kyoto, Japan</nlm:aff></affiliation></author><author><name sortKey="Sagayama, Hiroyuki" sort="Sagayama, Hiroyuki" uniqKey="Sagayama H" first="Hiroyuki" last="Sagayama">Hiroyuki Sagayama</name><affiliation><nlm:aff id="aff7">Faculty of Health and Sport Sciences, University of Tsukuba, Ibaraki, Japan</nlm:aff></affiliation></author><author><name sortKey="Berman, Elena S F" sort="Berman, Elena S F" uniqKey="Berman E" first="Elena S. F." last="Berman">Elena S. F. Berman</name><affiliation><nlm:aff id="aff8">Berman Scientific Consulting, Mountain View, CA, USA</nlm:aff></affiliation></author><author><name sortKey="Ainslie, Philip N" sort="Ainslie, Philip N" uniqKey="Ainslie P" first="Philip N." last="Ainslie">Philip N. Ainslie</name><affiliation><nlm:aff id="aff9">Research Institute for Sport and Exercise Sciences, Liverpool John Moores University, Liverpool, UK</nlm:aff></affiliation></author><author><name sortKey="Andersen, Lene F" sort="Andersen, Lene F" uniqKey="Andersen L" first="Lene F." last="Andersen">Lene F. Andersen</name><affiliation><nlm:aff id="aff10">Department of Nutrition, Institute of Basic Medical Sciences, University of Oslo, 0317 Oslo, Norway</nlm:aff></affiliation></author><author><name sortKey="Anderson, Liam J" sort="Anderson, Liam J" uniqKey="Anderson L" first="Liam J." last="Anderson">Liam J. Anderson</name><affiliation><nlm:aff id="aff9">Research Institute for Sport and Exercise Sciences, Liverpool John Moores University, Liverpool, UK</nlm:aff></affiliation><affiliation><nlm:aff id="aff11">Crewe Alexandra Football Club, Crewe, UK</nlm:aff></affiliation></author><author><name sortKey="Arab, Lenore" sort="Arab, Lenore" uniqKey="Arab L" first="Lenore" last="Arab">Lenore Arab</name><affiliation><nlm:aff id="aff12">David Geffen School of Medicine, University of California, Los Angeles, Los Angeles, CA, USA</nlm:aff></affiliation></author><author><name sortKey="Baddou, Issaad" sort="Baddou, Issaad" uniqKey="Baddou I" first="Issaad" last="Baddou">Issaad Baddou</name><affiliation><nlm:aff id="aff13">Unité Mixte de Recherche en Nutrition et Alimentation, CNESTEN- Université Ibn Tofail URAC39, Regional Designated Center of Nutrition Associated with AFRA/IAEA, Rabat, Morocco</nlm:aff></affiliation></author><author><name sortKey="Bedu Addo, Kweku" sort="Bedu Addo, Kweku" uniqKey="Bedu Addo K" first="Kweku" last="Bedu-Addo">Kweku Bedu-Addo</name><affiliation><nlm:aff id="aff14">Department of Physiology, Kwame Nkrumah University of Science and Technology, Kumasi, Ghana</nlm:aff></affiliation></author><author><name sortKey="Blaak, Ellen E" sort="Blaak, Ellen E" uniqKey="Blaak E" first="Ellen E." last="Blaak">Ellen E. Blaak</name><affiliation><nlm:aff id="aff15">Maastricht University, Maastricht, the Netherlands</nlm:aff></affiliation></author><author><name sortKey="Blanc, Stephane" sort="Blanc, Stephane" uniqKey="Blanc S" first="Stephane" last="Blanc">Stephane Blanc</name><affiliation><nlm:aff id="aff16">Nutritional Sciences, University of Wisconsin, Madison, WI, USA</nlm:aff></affiliation><affiliation><nlm:aff id="aff17">Institut Pluridisciplinaire Hubert Curien, CNRS Université de Strasbourg, UMR7178, Strasbourg, France</nlm:aff></affiliation></author><author><name sortKey="Bonomi, Alberto G" sort="Bonomi, Alberto G" uniqKey="Bonomi A" first="Alberto G." last="Bonomi">Alberto G. Bonomi</name><affiliation><nlm:aff id="aff18">Phillips Research, Eindhoven, the Netherlands</nlm:aff></affiliation></author><author><name sortKey="Bouten, Carlijn V C" sort="Bouten, Carlijn V C" uniqKey="Bouten C" first="Carlijn V. C." last="Bouten">Carlijn V. C. Bouten</name><affiliation><nlm:aff id="aff19">Department of Biomedical Engineering and Institute for Complex Molecular Systems, Eindhoven University of Technology, Eindhoven, the Netherlands</nlm:aff></affiliation></author><author><name sortKey="Bovet, Pascal" sort="Bovet, Pascal" uniqKey="Bovet P" first="Pascal" last="Bovet">Pascal Bovet</name><affiliation><nlm:aff id="aff20">Institute of Social and Preventive Medicine, Lausanne University Hospital, Lausanne, Switzerland</nlm:aff></affiliation></author><author><name sortKey="Buchowski, Maciej S" sort="Buchowski, Maciej S" uniqKey="Buchowski M" first="Maciej S." last="Buchowski">Maciej S. Buchowski</name><affiliation><nlm:aff id="aff21">Division of Gastroenterology, Hepatology and Nutrition, Department of Medicine, Vanderbilt University, Nashville, TN, USA</nlm:aff></affiliation></author><author><name sortKey="Butte, Nancy F" sort="Butte, Nancy F" uniqKey="Butte N" first="Nancy F." last="Butte">Nancy F. Butte</name><affiliation><nlm:aff id="aff22">Department of Pediatrics, Baylor College of Medicine, USDA/ARS Children’s Nutrition Research Center, Houston, TX, USA</nlm:aff></affiliation></author><author><name sortKey="Camps, Stefan G J A" sort="Camps, Stefan G J A" uniqKey="Camps S" first="Stefan G. J. A." last="Camps">Stefan G. J. A. Camps</name><affiliation><nlm:aff id="aff15">Maastricht University, Maastricht, the Netherlands</nlm:aff></affiliation></author><author><name sortKey="Close, Graeme L" sort="Close, Graeme L" uniqKey="Close G" first="Graeme L." last="Close">Graeme L. Close</name><affiliation><nlm:aff id="aff9">Research Institute for Sport and Exercise Sciences, Liverpool John Moores University, Liverpool, UK</nlm:aff></affiliation></author><author><name sortKey="Cooper, Jamie A" sort="Cooper, Jamie A" uniqKey="Cooper J" first="Jamie A." last="Cooper">Jamie A. Cooper</name><affiliation><nlm:aff id="aff16">Nutritional Sciences, University of Wisconsin, Madison, WI, USA</nlm:aff></affiliation></author><author><name sortKey="Creasy, Seth A" sort="Creasy, Seth A" uniqKey="Creasy S" first="Seth A." last="Creasy">Seth A. Creasy</name><affiliation><nlm:aff id="aff23">Division of Endocrinology, Metabolism and Diabetes, University of Colorado Anschulz Medical Campus, Aurora, CO, USA</nlm:aff></affiliation></author><author><name sortKey="Das, Sai Krupa" sort="Das, Sai Krupa" uniqKey="Das S" first="Sai Krupa" last="Das">Sai Krupa Das</name><affiliation><nlm:aff id="aff24">Friedman School of Nutrition Science and Policy, Tufts University, 150 Harrison Avenue, Boston, MA, USA</nlm:aff></affiliation></author><author><name sortKey="Cooper, Richard" sort="Cooper, Richard" uniqKey="Cooper R" first="Richard" last="Cooper">Richard Cooper</name><affiliation><nlm:aff id="aff25">Department of Public Health Sciences, Parkinson School of Health Sciences and Public Health, Loyola University, Maywood, IL, USA</nlm:aff></affiliation></author><author><name sortKey="Dugas, Lara R" sort="Dugas, Lara R" uniqKey="Dugas L" first="Lara R." last="Dugas">Lara R. Dugas</name><affiliation><nlm:aff id="aff25">Department of Public Health Sciences, Parkinson School of Health Sciences and Public Health, Loyola University, Maywood, IL, USA</nlm:aff></affiliation></author><author><name sortKey="Ebbeling, Cara B" sort="Ebbeling, Cara B" uniqKey="Ebbeling C" first="Cara B." last="Ebbeling">Cara B. Ebbeling</name><affiliation><nlm:aff id="aff26">Boston Children’s Hospital, Boston, MA, USA</nlm:aff></affiliation></author><author><name sortKey="Ekelund, Ulf" sort="Ekelund, Ulf" uniqKey="Ekelund U" first="Ulf" last="Ekelund">Ulf Ekelund</name><affiliation><nlm:aff id="aff27">Department of Sport Medicine, Norwegian School of Sport Sciences, Oslo, Norway</nlm:aff></affiliation></author><author><name sortKey="Entringer, Sonja" sort="Entringer, Sonja" uniqKey="Entringer S" first="Sonja" last="Entringer">Sonja Entringer</name><affiliation><nlm:aff id="aff28">Charité – Universitätsmedizin Berlin, corporate member of Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health (BIH), Institute of Medical Psychology, Berlin, Germany</nlm:aff></affiliation><affiliation><nlm:aff id="aff29">University of California, Irvine, Irvine, CA, USA</nlm:aff></affiliation></author><author><name sortKey="Forrester, Terrence" sort="Forrester, Terrence" uniqKey="Forrester T" first="Terrence" last="Forrester">Terrence Forrester</name><affiliation><nlm:aff id="aff30">Solutions for Developing Countries, University of the West Indies, Mona, Kingston, Jamaica</nlm:aff></affiliation></author><author><name sortKey="Fudge, Barry W" sort="Fudge, Barry W" uniqKey="Fudge B" first="Barry W." last="Fudge">Barry W. Fudge</name><affiliation><nlm:aff id="aff31">University of Glasgow, Glasgow, UK</nlm:aff></affiliation></author><author><name sortKey="Goris, Annelies H" sort="Goris, Annelies H" uniqKey="Goris A" first="Annelies H." last="Goris">Annelies H. Goris</name><affiliation><nlm:aff id="aff15">Maastricht University, Maastricht, the Netherlands</nlm:aff></affiliation></author><author><name sortKey="Gurven, Michael" sort="Gurven, Michael" uniqKey="Gurven M" first="Michael" last="Gurven">Michael Gurven</name><affiliation><nlm:aff id="aff32">Department of Anthropology, University of California, Santa Barbara, Santa Barbara, CA, USA</nlm:aff></affiliation></author><author><name sortKey="Hambly, Catherine" sort="Hambly, Catherine" uniqKey="Hambly C" first="Catherine" last="Hambly">Catherine Hambly</name><affiliation><nlm:aff id="aff2">Institute of Biological and Environmental Sciences, University of Aberdeen, Aberdeen, UK</nlm:aff></affiliation></author><author><name sortKey="El Hamdouchi, Asmaa" sort="El Hamdouchi, Asmaa" uniqKey="El Hamdouchi A" first="Asmaa" last="El Hamdouchi">Asmaa El Hamdouchi</name><affiliation><nlm:aff id="aff13">Unité Mixte de Recherche en Nutrition et Alimentation, CNESTEN- Université Ibn Tofail URAC39, Regional Designated Center of Nutrition Associated with AFRA/IAEA, Rabat, Morocco</nlm:aff></affiliation></author><author><name sortKey="Hoos, Marije B" sort="Hoos, Marije B" uniqKey="Hoos M" first="Marije B." last="Hoos">Marije B. Hoos</name><affiliation><nlm:aff id="aff15">Maastricht University, Maastricht, the Netherlands</nlm:aff></affiliation></author><author><name sortKey="Hu, Sumei" sort="Hu, Sumei" uniqKey="Hu S" first="Sumei" last="Hu">Sumei Hu</name><affiliation><nlm:aff id="aff3">State Key Laboratory of Molecular Developmental Biology, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing, China</nlm:aff></affiliation></author><author><name sortKey="Joonas, Noorjehan" sort="Joonas, Noorjehan" uniqKey="Joonas N" first="Noorjehan" last="Joonas">Noorjehan Joonas</name><affiliation><nlm:aff id="aff33">Central Health Laboratory, Ministry of Health and Wellness, Port Louis, Mauritius</nlm:aff></affiliation></author><author><name sortKey="Joosen, Annemiek M" sort="Joosen, Annemiek M" uniqKey="Joosen A" first="Annemiek M." last="Joosen">Annemiek M. Joosen</name><affiliation><nlm:aff id="aff15">Maastricht University, Maastricht, the Netherlands</nlm:aff></affiliation></author><author><name sortKey="Katzmarzyk, Peter" sort="Katzmarzyk, Peter" uniqKey="Katzmarzyk P" first="Peter" last="Katzmarzyk">Peter Katzmarzyk</name><affiliation><nlm:aff id="aff34">Pennington Biomedical Research Center, Baton Rouge, LA, USA</nlm:aff></affiliation></author><author><name sortKey="Kempen, Kitty P" sort="Kempen, Kitty P" uniqKey="Kempen K" first="Kitty P." last="Kempen">Kitty P. Kempen</name><affiliation><nlm:aff id="aff15">Maastricht University, Maastricht, the Netherlands</nlm:aff></affiliation></author><author><name sortKey="Kimura, Misaka" sort="Kimura, Misaka" uniqKey="Kimura M" first="Misaka" last="Kimura">Misaka Kimura</name><affiliation><nlm:aff id="aff6">Institute for Active Health, Kyoto University of Advanced Science, Kyoto, Japan</nlm:aff></affiliation></author><author><name sortKey="Kraus, William E" sort="Kraus, William E" uniqKey="Kraus W" first="William E." last="Kraus">William E. Kraus</name><affiliation><nlm:aff id="aff35">Department of Medicine, Duke University, Durham, NC, USA</nlm:aff></affiliation></author><author><name sortKey="Kushner, Robert F" sort="Kushner, Robert F" uniqKey="Kushner R" first="Robert F." last="Kushner">Robert F. Kushner</name><affiliation><nlm:aff id="aff36">Northwestern University, Chicago, IL, USA</nlm:aff></affiliation></author><author><name sortKey="Lambert, Estelle V" sort="Lambert, Estelle V" uniqKey="Lambert E" first="Estelle V." last="Lambert">Estelle V. Lambert</name><affiliation><nlm:aff id="aff37">Research Unit for Exercise Science and Sports Medicine, University of Cape Town, Cape Town, South Africa</nlm:aff></affiliation></author><author><name sortKey="Leonard, William R" sort="Leonard, William R" uniqKey="Leonard W" first="William R." last="Leonard">William R. Leonard</name><affiliation><nlm:aff id="aff38">Department of Anthropology, Northwestern University, Evanston, IL, USA</nlm:aff></affiliation></author><author><name sortKey="Lessan, Nader" sort="Lessan, Nader" uniqKey="Lessan N" first="Nader" last="Lessan">Nader Lessan</name><affiliation><nlm:aff id="aff39">Imperial College London Diabetes Centre, Imperial College London, London, UK</nlm:aff></affiliation></author><author><name sortKey="Ludwig, David S" sort="Ludwig, David S" uniqKey="Ludwig D" first="David S." last="Ludwig">David S. Ludwig</name><affiliation><nlm:aff id="aff26">Boston Children’s Hospital, Boston, MA, USA</nlm:aff></affiliation></author><author><name sortKey="Martin, Corby K" sort="Martin, Corby K" uniqKey="Martin C" first="Corby K." last="Martin">Corby K. Martin</name><affiliation><nlm:aff id="aff34">Pennington Biomedical Research Center, Baton Rouge, LA, USA</nlm:aff></affiliation></author><author><name sortKey="Medin, Anine C" sort="Medin, Anine C" uniqKey="Medin A" first="Anine C." last="Medin">Anine C. Medin</name><affiliation><nlm:aff id="aff10">Department of Nutrition, Institute of Basic Medical Sciences, University of Oslo, 0317 Oslo, Norway</nlm:aff></affiliation><affiliation><nlm:aff id="aff40">Department of Nutrition and Public Health, Faculty of Health and Sport Sciences, University of Agder, 4630 Kristiansand, Norway</nlm:aff></affiliation></author><author><name sortKey="Meijer, Erwin P" sort="Meijer, Erwin P" uniqKey="Meijer E" first="Erwin P." last="Meijer">Erwin P. Meijer</name><affiliation><nlm:aff id="aff15">Maastricht University, Maastricht, the Netherlands</nlm:aff></affiliation></author><author><name sortKey="Morehen, James C" sort="Morehen, James C" uniqKey="Morehen J" first="James C." last="Morehen">James C. Morehen</name><affiliation><nlm:aff id="aff9">Research Institute for Sport and Exercise Sciences, Liverpool John Moores University, Liverpool, UK</nlm:aff></affiliation><affiliation><nlm:aff id="aff41">The FA Group, Burton-Upon-Trent, Staffordshire, UK</nlm:aff></affiliation></author><author><name sortKey="Morton, James P" sort="Morton, James P" uniqKey="Morton J" first="James P." last="Morton">James P. Morton</name><affiliation><nlm:aff id="aff9">Research Institute for Sport and Exercise Sciences, Liverpool John Moores University, Liverpool, UK</nlm:aff></affiliation></author><author><name sortKey="Neuhouser, Marian L" sort="Neuhouser, Marian L" uniqKey="Neuhouser M" first="Marian L." last="Neuhouser">Marian L. Neuhouser</name><affiliation><nlm:aff id="aff42">Division of Public Health Sciences, Fred Hutchinson Cancer Research Center and School of Public Health, University of Washington, Seattle, WA, USA</nlm:aff></affiliation></author><author><name sortKey="Nicklas, Theresa A" sort="Nicklas, Theresa A" uniqKey="Nicklas T" first="Theresa A." last="Nicklas">Theresa A. Nicklas</name><affiliation><nlm:aff id="aff22">Department of Pediatrics, Baylor College of Medicine, USDA/ARS Children’s Nutrition Research Center, Houston, TX, USA</nlm:aff></affiliation></author><author><name sortKey="Ojiambo, Robert M" sort="Ojiambo, Robert M" uniqKey="Ojiambo R" first="Robert M." last="Ojiambo">Robert M. Ojiambo</name><affiliation><nlm:aff id="aff43">Moi University, Eldoret, Kenya</nlm:aff></affiliation><affiliation><nlm:aff id="aff44">University of Global Health Equity, Kigali, Rwanda</nlm:aff></affiliation></author><author><name sortKey="Pietil Inen, Kirsi H" sort="Pietil Inen, Kirsi H" uniqKey="Pietil Inen K" first="Kirsi H." last="Pietil Inen">Kirsi H. Pietil Inen</name><affiliation><nlm:aff id="aff45">Helsinki University Central Hospital, Helsinki, Finland</nlm:aff></affiliation></author><author><name sortKey="Pitsiladis, Yannis P" sort="Pitsiladis, Yannis P" uniqKey="Pitsiladis Y" first="Yannis P." last="Pitsiladis">Yannis P. Pitsiladis</name><affiliation><nlm:aff id="aff46">University of Brighton, Eastbourne, UK</nlm:aff></affiliation></author><author><name sortKey="Plange Rhule, Jacob" sort="Plange Rhule, Jacob" uniqKey="Plange Rhule J" first="Jacob" last="Plange-Rhule">Jacob Plange-Rhule</name><affiliation><nlm:aff id="aff47">Department of Physiology, Kwame Nkrumah University of Science and Technology, Kumasi, Ghana</nlm:aff></affiliation></author><author><name sortKey="Plasqui, Guy" sort="Plasqui, Guy" uniqKey="Plasqui G" first="Guy" last="Plasqui">Guy Plasqui</name><affiliation><nlm:aff id="aff48">Department of Nutrition and Movement Sciences, Maastricht University, Maastricht, the Netherlands</nlm:aff></affiliation></author><author><name sortKey="Prentice, Ross L" sort="Prentice, Ross L" uniqKey="Prentice R" first="Ross L." last="Prentice">Ross L. Prentice</name><affiliation><nlm:aff id="aff42">Division of Public Health Sciences, Fred Hutchinson Cancer Research Center and School of Public Health, University of Washington, Seattle, WA, USA</nlm:aff></affiliation></author><author><name sortKey="Rabinovich, Roberto A" sort="Rabinovich, Roberto A" uniqKey="Rabinovich R" first="Roberto A." last="Rabinovich">Roberto A. Rabinovich</name><affiliation><nlm:aff id="aff49">University of Edinburgh, Edinburgh, UK</nlm:aff></affiliation></author><author><name sortKey="Racette, Susan B" sort="Racette, Susan B" uniqKey="Racette S" first="Susan B." last="Racette">Susan B. Racette</name><affiliation><nlm:aff id="aff24">Friedman School of Nutrition Science and Policy, Tufts University, 150 Harrison Avenue, Boston, MA, USA</nlm:aff></affiliation></author><author><name sortKey="Raichlen, David A" sort="Raichlen, David A" uniqKey="Raichlen D" first="David A." last="Raichlen">David A. Raichlen</name><affiliation><nlm:aff id="aff50">Biological Sciences and Anthropology, University of Southern California, Los Angeles, CA, USA</nlm:aff></affiliation></author><author><name sortKey="Ravussin, Eric" sort="Ravussin, Eric" uniqKey="Ravussin E" first="Eric" last="Ravussin">Eric Ravussin</name><affiliation><nlm:aff id="aff34">Pennington Biomedical Research Center, Baton Rouge, LA, USA</nlm:aff></affiliation></author><author><name sortKey="Reynolds, Rebecca M" sort="Reynolds, Rebecca M" uniqKey="Reynolds R" first="Rebecca M." last="Reynolds">Rebecca M. Reynolds</name><affiliation><nlm:aff id="aff51">Centre for Cardiovascular Sciences, Queen’s Medical Research Institute, University of Edinburgh, Edinburgh, UK</nlm:aff></affiliation></author><author><name sortKey="Roberts, Susan B" sort="Roberts, Susan B" uniqKey="Roberts S" first="Susan B." last="Roberts">Susan B. Roberts</name><affiliation><nlm:aff id="aff24">Friedman School of Nutrition Science and Policy, Tufts University, 150 Harrison Avenue, Boston, MA, USA</nlm:aff></affiliation></author><author><name sortKey="Schuit, Albertine J" sort="Schuit, Albertine J" uniqKey="Schuit A" first="Albertine J." last="Schuit">Albertine J. Schuit</name><affiliation><nlm:aff id="aff52">University of Tilburg, Tilburg, the Netherlands</nlm:aff></affiliation></author><author><name sortKey="Sjodin, Anders M" sort="Sjodin, Anders M" uniqKey="Sjodin A" first="Anders M." last="Sjödin">Anders M. Sjödin</name><affiliation><nlm:aff id="aff53">Department of Nutrition, Exercise and Sports, Copenhagen University, Copenhagen, Denmark</nlm:aff></affiliation></author><author><name sortKey="Stice, Eric" sort="Stice, Eric" uniqKey="Stice E" first="Eric" last="Stice">Eric Stice</name><affiliation><nlm:aff id="aff54">Stanford University, Stanford, CA, USA</nlm:aff></affiliation></author><author><name sortKey="Urlacher, Samuel S" sort="Urlacher, Samuel S" uniqKey="Urlacher S" first="Samuel S." last="Urlacher">Samuel S. Urlacher</name><affiliation><nlm:aff id="aff55">Department of Anthropology, Baylor University, Waco, TX, USA</nlm:aff></affiliation></author><author><name sortKey="Valenti, Giulio" sort="Valenti, Giulio" uniqKey="Valenti G" first="Giulio" last="Valenti">Giulio Valenti</name><affiliation><nlm:aff id="aff15">Maastricht University, Maastricht, the Netherlands</nlm:aff></affiliation></author><author><name sortKey="Van Etten, Ludo M" sort="Van Etten, Ludo M" uniqKey="Van Etten L" first="Ludo M." last="Van Etten">Ludo M. Van Etten</name><affiliation><nlm:aff id="aff15">Maastricht University, Maastricht, the Netherlands</nlm:aff></affiliation></author><author><name sortKey="Van Mil, Edgar A" sort="Van Mil, Edgar A" uniqKey="Van Mil E" first="Edgar A." last="Van Mil">Edgar A. Van Mil</name><affiliation><nlm:aff id="aff56">Maastricht and Lifestyle Medicine Center for Children, Jeroen Bosch Hospital’s-Hertogenbosch, Maastricht University, Maastricht, the Netherlands</nlm:aff></affiliation></author><author><name sortKey="Wells, Jonathan C K" sort="Wells, Jonathan C K" uniqKey="Wells J" first="Jonathan C. K." last="Wells">Jonathan C. K. Wells</name><affiliation><nlm:aff id="aff57">Population, Policy and Practice Research and Teaching Department, UCL Great Ormond Street Institute of Child Health, London, UK</nlm:aff></affiliation></author><author><name sortKey="Wilson, George" sort="Wilson, George" uniqKey="Wilson G" first="George" last="Wilson">George Wilson</name><affiliation><nlm:aff id="aff9">Research Institute for Sport and Exercise Sciences, Liverpool John Moores University, Liverpool, UK</nlm:aff></affiliation></author><author><name sortKey="Wood, Brian M" sort="Wood, Brian M" uniqKey="Wood B" first="Brian M." last="Wood">Brian M. Wood</name><affiliation><nlm:aff id="aff58">University of California, Los Angeles, Los Angeles, CA, USA</nlm:aff></affiliation><affiliation><nlm:aff id="aff59">Department of Human Behavior, Ecology, and Culture, Max Planck Institute for Evolutionary Anthropology, Leipzig, Germany</nlm:aff></affiliation></author><author><name sortKey="Yanovski, Jack" sort="Yanovski, Jack" uniqKey="Yanovski J" first="Jack" last="Yanovski">Jack Yanovski</name><affiliation><nlm:aff id="aff60">Growth and Obesity, Division of Intramural Research, NIH, Bethesda, MD, USA</nlm:aff></affiliation></author><author><name sortKey="Yoshida, Tsukasa" sort="Yoshida, Tsukasa" uniqKey="Yoshida T" first="Tsukasa" last="Yoshida">Tsukasa Yoshida</name><affiliation><nlm:aff id="aff5">National Institute of Health and Nutrition, National Institutes of Biomedical Innovation, Health and Nutrition, Tokyo, Japan</nlm:aff></affiliation></author><author><name sortKey="Zhang, Xueying" sort="Zhang, Xueying" uniqKey="Zhang X" first="Xueying" last="Zhang">Xueying Zhang</name><affiliation><nlm:aff id="aff1">Center for Energy Metabolism and Reproduction, Shenzhen Institutes of Advanced Technology, Chinese Academy of Sciences, Shenzhen, China</nlm:aff></affiliation><affiliation><nlm:aff id="aff2">Institute of Biological and Environmental Sciences, University of Aberdeen, Aberdeen, UK</nlm:aff></affiliation></author><author><name sortKey="Murphy Alford, Alexia J" sort="Murphy Alford, Alexia J" uniqKey="Murphy Alford A" first="Alexia J." last="Murphy-Alford">Alexia J. Murphy-Alford</name><affiliation><nlm:aff id="aff61">Nutritional and Health Related Environmental Studies Section, Division of Human Health, International Atomic Energy Agency, Vienna, Austria</nlm:aff></affiliation></author><author><name sortKey="Loechl, Cornelia U" sort="Loechl, Cornelia U" uniqKey="Loechl C" first="Cornelia U." last="Loechl">Cornelia U. Loechl</name><affiliation><nlm:aff id="aff61">Nutritional and Health Related Environmental Studies Section, Division of Human Health, International Atomic Energy Agency, Vienna, Austria</nlm:aff></affiliation></author><author><name sortKey="Melanson, Edward L" sort="Melanson, Edward L" uniqKey="Melanson E" first="Edward L." last="Melanson">Edward L. Melanson</name><affiliation><nlm:aff id="aff23">Division of Endocrinology, Metabolism and Diabetes, University of Colorado Anschulz Medical Campus, Aurora, CO, USA</nlm:aff></affiliation><affiliation><nlm:aff id="aff62">Eastern Colorado VA Geriatric Research, Education and Clinical Center, Aurora, CO, USA</nlm:aff></affiliation><affiliation><nlm:aff id="aff63">Division of Geriatrics, University of Colorado Anschutz Medical Campus, Aurora, CO, USA</nlm:aff></affiliation></author><author><name sortKey="Luke, Amy H" sort="Luke, Amy H" uniqKey="Luke A" first="Amy H." last="Luke">Amy H. Luke</name><affiliation><nlm:aff id="aff64">Division of Epidemiology, Department of Public Health Sciences, Loyola University School of Medicine, Maywood, IL, USA</nlm:aff></affiliation></author><author><name sortKey="Pontzer, Herman" sort="Pontzer, Herman" uniqKey="Pontzer H" first="Herman" last="Pontzer">Herman Pontzer</name><affiliation><nlm:aff id="aff65">Evolutionary Anthropology, Duke University, Durham, NC, USA</nlm:aff></affiliation><affiliation><nlm:aff id="aff66">Duke Global Health Institute, Duke University, Durham, NC, USA</nlm:aff></affiliation></author><author><name sortKey="Rood, Jennifer" sort="Rood, Jennifer" uniqKey="Rood J" first="Jennifer" last="Rood">Jennifer Rood</name><affiliation><nlm:aff id="aff34">Pennington Biomedical Research Center, Baton Rouge, LA, USA</nlm:aff></affiliation></author><author><name sortKey="Schoeller, Dale A" sort="Schoeller, Dale A" uniqKey="Schoeller D" first="Dale A." last="Schoeller">Dale A. Schoeller</name><affiliation><nlm:aff id="aff67">Biotech Center and Nutritional Sciences, University of Wisconsin, Madison, WI, USA</nlm:aff></affiliation></author><author><name sortKey="Westerterp, Klaas R" sort="Westerterp, Klaas R" uniqKey="Westerterp K" first="Klaas R." last="Westerterp">Klaas R. Westerterp</name><affiliation><nlm:aff id="aff68">School of Nutrition and Translational Research in Metabolism, University of Maastricht, Maastricht, the Netherlands</nlm:aff></affiliation></author><author><name sortKey="Wong, William W" sort="Wong, William W" uniqKey="Wong W" first="William W." last="Wong">William W. Wong</name><affiliation><nlm:aff id="aff22">Department of Pediatrics, Baylor College of Medicine, USDA/ARS Children’s Nutrition Research Center, Houston, TX, USA</nlm:aff></affiliation></author></analytic><series><title level="j">Cell Reports Medicine</title><idno type="eISSN">2666-3791</idno><imprint><date when="2021">2021</date></imprint></series></biblStruct></sourceDesc></fileDesc><profileDesc><textClass></textClass></profileDesc></teiHeader><front><div type="abstract" xml:lang="en"><title>Summary</title><p>The doubly labeled water (DLW) method measures total energy expenditure (TEE) in free-living subjects. Several equations are used to convert isotopic data into TEE. Using the International Atomic Energy Agency (IAEA) DLW database (5,756 measurements of adults and children), we show considerable variability is introduced by different equations. The estimated rCO<sub>2</sub> is sensitive to the dilution space ratio (DSR) of the two isotopes. Based on performance in validation studies, we propose a new equation based on a new estimate of the mean DSR. The DSR is lower at low body masses (<10 kg). Using data for 1,021 babies and infants, we show that the DSR varies non-linearly with body mass between 0 and 10 kg. Using this relationship to predict DSR from weight provides an equation for rCO<sub>2</sub> over this size range that agrees well with indirect calorimetry (average difference 0.64%; SD = 12.2%). We propose adoption of these equations in future studies.</p></div></front><back><div1 type="bibliography"><listBibl><biblStruct><analytic><author><name sortKey="Lifson, N" uniqKey="Lifson N">N. Lifson</name></author><author><name sortKey="Gordon, G B" uniqKey="Gordon G">G.B. Gordon</name></author><author><name sortKey="Mcclintock, R" uniqKey="Mcclintock R">R. McCLINTOCK</name></author></analytic></biblStruct><biblStruct><analytic><author><name sortKey="Lifson, N" uniqKey="Lifson N">N. Lifson</name></author></analytic></biblStruct><biblStruct><analytic><author><name sortKey="Speakman, J R" uniqKey="Speakman J">J.R. Speakman</name></author></analytic></biblStruct><biblStruct><analytic><author><name sortKey="Nagy, K A" uniqKey="Nagy K">K.A. Nagy</name></author></analytic></biblStruct><biblStruct><analytic><author><name sortKey="Schoeller, D A" uniqKey="Schoeller D">D.A. Schoeller</name></author><author><name sortKey="Van Santen, E" uniqKey="Van Santen E">E. van Santen</name></author></analytic></biblStruct><biblStruct><analytic><author><name sortKey="Westerterp, K R" uniqKey="Westerterp K">K.R. Westerterp</name></author><author><name sortKey="Saris, W H M" uniqKey="Saris W">W.H.M. Saris</name></author><author><name sortKey="Van Es, M" uniqKey="Van Es M">M. van Es</name></author><author><name sortKey="Ten Hoor, F" uniqKey="Ten Hoor F">F. ten Hoor</name></author></analytic></biblStruct><biblStruct><analytic><author><name sortKey="Klein, P D" uniqKey="Klein P">P.D. Klein</name></author><author><name sortKey="James, W P" uniqKey="James W">W.P. James</name></author><author><name sortKey="Wong, W W" uniqKey="Wong W">W.W. Wong</name></author><author><name sortKey="Irving, C S" uniqKey="Irving C">C.S. Irving</name></author><author><name sortKey="Murgatroyd, P R" uniqKey="Murgatroyd P">P.R. Murgatroyd</name></author><author><name sortKey="Cabrera, M" uniqKey="Cabrera M">M. Cabrera</name></author><author><name sortKey="Dallosso, H M" uniqKey="Dallosso H">H.M. Dallosso</name></author><author><name sortKey="Klein, E R" uniqKey="Klein E">E.R. Klein</name></author><author><name sortKey="Nichols, B L" uniqKey="Nichols B">B.L. Nichols</name></author></analytic></biblStruct><biblStruct><analytic><author><name sortKey="Speakman, J R" uniqKey="Speakman J">J.R. Speakman</name></author><author><name sortKey="Pontzer, H" uniqKey="Pontzer H">H. Pontzer</name></author><author><name sortKey="Rood, J" uniqKey="Rood J">J. Rood</name></author><author><name sortKey="Sagayama, H" uniqKey="Sagayama H">H. Sagayama</name></author><author><name sortKey="Schoeller, D A" uniqKey="Schoeller D">D.A. Schoeller</name></author><author><name sortKey="Westerterp, K R" uniqKey="Westerterp K">K.R. Westerterp</name></author><author><name sortKey="Wong, W W" uniqKey="Wong W">W.W. Wong</name></author><author><name sortKey="Yamada, Y" uniqKey="Yamada Y">Y. Yamada</name></author><author><name sortKey="Loechl, C" uniqKey="Loechl C">C. Loechl</name></author><author><name sortKey="Murphy Alford, A J" uniqKey="Murphy Alford A">A.J. Murphy-Alford</name></author></analytic></biblStruct><biblStruct><analytic><author><name sortKey="Dugas, L R" uniqKey="Dugas L">L.R. Dugas</name></author><author><name sortKey="Harders, R" uniqKey="Harders R">R. Harders</name></author><author><name sortKey="Merrill, S" uniqKey="Merrill S">S. Merrill</name></author><author><name sortKey="Ebersole, K" uniqKey="Ebersole K">K. Ebersole</name></author><author><name sortKey="Shoham, D A" uniqKey="Shoham D">D.A. Shoham</name></author><author><name sortKey="Rush, E C" uniqKey="Rush E">E.C. Rush</name></author><author><name sortKey="Assah, F K" uniqKey="Assah F">F.K. Assah</name></author><author><name sortKey="Forrester, T" uniqKey="Forrester T">T. Forrester</name></author><author><name sortKey="Durazo Arvizu, R A" uniqKey="Durazo Arvizu R">R.A. Durazo-Arvizu</name></author><author><name sortKey="Luke, A" uniqKey="Luke A">A. Luke</name></author></analytic></biblStruct><biblStruct><analytic><author><name sortKey="Schoeller, D A" uniqKey="Schoeller D">D.A. Schoeller</name></author><author><name sortKey="Allison, D B" uniqKey="Allison D">D.B. Allison</name></author></analytic></biblStruct><biblStruct></biblStruct><biblStruct><analytic><author><name sortKey="Schoeller, D A" uniqKey="Schoeller D">D.A. Schoeller</name></author><author><name sortKey="Webb, P" uniqKey="Webb P">P. Webb</name></author></analytic></biblStruct><biblStruct><analytic><author><name sortKey="Westerterp, K R" uniqKey="Westerterp K">K.R. Westerterp</name></author><author><name sortKey="Brouns, F" uniqKey="Brouns F">F. Brouns</name></author><author><name sortKey="Saris, W H" uniqKey="Saris W">W.H. Saris</name></author><author><name sortKey="Ten Hoor, F" uniqKey="Ten Hoor F">F. ten Hoor</name></author></analytic></biblStruct><biblStruct><analytic><author><name sortKey="Seale, J L" uniqKey="Seale J">J.L. Seale</name></author><author><name sortKey="Conway, J M" uniqKey="Conway J">J.M. Conway</name></author><author><name sortKey="Canary, J J" uniqKey="Canary J">J.J. Canary</name></author></analytic></biblStruct><biblStruct><analytic><author><name sortKey="Schoeller, D A" uniqKey="Schoeller D">D.A. Schoeller</name></author><author><name sortKey="Ravussin, E" uniqKey="Ravussin E">E. Ravussin</name></author><author><name sortKey="Schutz, Y" uniqKey="Schutz Y">Y. Schutz</name></author><author><name sortKey="Acheson, K J" uniqKey="Acheson K">K.J. Acheson</name></author><author><name sortKey="Baertschi, P" uniqKey="Baertschi P">P. Baertschi</name></author><author><name sortKey="Jequier, E" uniqKey="Jequier E">E. Jéquier</name></author></analytic></biblStruct><biblStruct><analytic><author><name sortKey="Ravussin, E" uniqKey="Ravussin E">E. Ravussin</name></author><author><name sortKey="Harper, I T" uniqKey="Harper I">I.T. Harper</name></author><author><name sortKey="Rising, R" uniqKey="Rising R">R. Rising</name></author><author><name sortKey="Bogardus, C" uniqKey="Bogardus C">C. Bogardus</name></author></analytic></biblStruct><biblStruct><analytic><author><name sortKey="Melanson, E L" uniqKey="Melanson E">E.L. Melanson</name></author><author><name sortKey="Swibas, T" uniqKey="Swibas T">T. Swibas</name></author><author><name sortKey="Kohrt, W M" uniqKey="Kohrt W">W.M. Kohrt</name></author><author><name sortKey="Catenacci, V A" uniqKey="Catenacci V">V.A. Catenacci</name></author><author><name sortKey="Creasy, S A" uniqKey="Creasy S">S.A. Creasy</name></author><author><name sortKey="Plasqui, G" uniqKey="Plasqui G">G. Plasqui</name></author><author><name sortKey="Wouters, L" uniqKey="Wouters L">L. Wouters</name></author><author><name sortKey="Speakman, J R" uniqKey="Speakman J">J.R. Speakman</name></author><author><name sortKey="Berman, E S F" uniqKey="Berman E">E.S.F. Berman</name></author></analytic></biblStruct><biblStruct><analytic><author><name sortKey="Schoeller, D A" uniqKey="Schoeller D">D.A. Schoeller</name></author></analytic></biblStruct><biblStruct><analytic><author><name sortKey="Racette, S B" uniqKey="Racette S">S.B. Racette</name></author><author><name sortKey="Schoeller, D A" uniqKey="Schoeller D">D.A. Schoeller</name></author><author><name sortKey="Luke, A H" uniqKey="Luke A">A.H. Luke</name></author><author><name sortKey="Shay, K" uniqKey="Shay K">K. Shay</name></author><author><name sortKey="Hnilicka, J" uniqKey="Hnilicka J">J. Hnilicka</name></author><author><name sortKey="Kushner, R F" uniqKey="Kushner R">R.F. Kushner</name></author></analytic></biblStruct><biblStruct><analytic><author><name sortKey="Sagayama, H" uniqKey="Sagayama H">H. Sagayama</name></author><author><name sortKey="Yamada, Y" uniqKey="Yamada Y">Y. Yamada</name></author><author><name sortKey="Racine, N M" uniqKey="Racine N">N.M. Racine</name></author><author><name sortKey="Shriver, T C" uniqKey="Shriver T">T.C. Shriver</name></author><author><name sortKey="Schoeller, D A" uniqKey="Schoeller D">D.A. Schoeller</name></author></analytic></biblStruct><biblStruct><analytic><author><name sortKey="Speakman, J R" uniqKey="Speakman J">J.R. Speakman</name></author><author><name sortKey="Nair, K S" uniqKey="Nair K">K.S. Nair</name></author><author><name sortKey="Goran, M I" uniqKey="Goran M">M.I. Goran</name></author></analytic></biblStruct><biblStruct><analytic><author><name sortKey="Coward, W A" uniqKey="Coward W">W.A. Coward</name></author><author><name sortKey="Prentice, A M" uniqKey="Prentice A">A.M. Prentice</name></author></analytic></biblStruct><biblStruct><analytic><author><name sortKey="Shanthini, R" uniqKey="Shanthini R">R. Shanthini</name></author></analytic></biblStruct><biblStruct><analytic><author><name sortKey="Weir, J B" uniqKey="Weir J">J.B. Weir</name></author></analytic></biblStruct><biblStruct><analytic><author><name sortKey="Bland, J M" uniqKey="Bland J">J.M. Bland</name></author><author><name sortKey="Altman, D G" uniqKey="Altman D">D.G. Altman</name></author></analytic></biblStruct><biblStruct><analytic><author><name sortKey="Wells, J C" uniqKey="Wells J">J.C. Wells</name></author><author><name sortKey="Ritz, P" uniqKey="Ritz P">P. Ritz</name></author><author><name sortKey="Davies, P S" uniqKey="Davies P">P.S. Davies</name></author><author><name sortKey="Coward, W A" uniqKey="Coward W">W.A. Coward</name></author></analytic></biblStruct><biblStruct><analytic><author><name sortKey="Roberts, S B" uniqKey="Roberts S">S.B. Roberts</name></author><author><name sortKey="Coward, W A" uniqKey="Coward W">W.A. Coward</name></author><author><name sortKey="Schlingenseipen, K H" uniqKey="Schlingenseipen K">K.H. Schlingenseipen</name></author><author><name sortKey="Nohria, V" uniqKey="Nohria V">V. Nohria</name></author><author><name sortKey="Lucas, A" uniqKey="Lucas A">A. Lucas</name></author></analytic></biblStruct><biblStruct><analytic><author><name sortKey="Westerterp, K R" uniqKey="Westerterp K">K.R. Westerterp</name></author><author><name sortKey="Lafeber, H N" uniqKey="Lafeber H">H.N. Lafeber</name></author><author><name sortKey="Sulkers, E J" uniqKey="Sulkers E">E.J. Sulkers</name></author><author><name sortKey="Sauer, P J J" uniqKey="Sauer P">P.J.J. Sauer</name></author></analytic></biblStruct><biblStruct><analytic><author><name sortKey="Jensen, C L" uniqKey="Jensen C">C.L. Jensen</name></author><author><name sortKey="Butte, N F" uniqKey="Butte N">N.F. Butte</name></author><author><name sortKey="Wong, W W" uniqKey="Wong W">W.W. Wong</name></author><author><name sortKey="Moon, J K" uniqKey="Moon J">J.K. Moon</name></author></analytic></biblStruct><biblStruct><analytic><author><name sortKey="Ritz, P" uniqKey="Ritz P">P. Ritz</name></author><author><name sortKey="Johnson, P G" uniqKey="Johnson P">P.G. Johnson</name></author><author><name sortKey="Coward, W A" uniqKey="Coward W">W.A. Coward</name></author></analytic></biblStruct><biblStruct><analytic><author><name sortKey="De Bruin, N C" uniqKey="De Bruin N">N.C. de Bruin</name></author><author><name sortKey="Degenhart, H J" uniqKey="Degenhart H">H.J. Degenhart</name></author><author><name sortKey="Gal, S" uniqKey="Gal S">S. Gàl</name></author><author><name sortKey="Westerterp, K R" uniqKey="Westerterp K">K.R. Westerterp</name></author><author><name sortKey="Stijnen, T" uniqKey="Stijnen T">T. Stijnen</name></author><author><name sortKey="Visser, H K" uniqKey="Visser H">H.K. Visser</name></author></analytic></biblStruct><biblStruct><analytic><author><name sortKey="Jones, P J H" uniqKey="Jones P">P.J.H. Jones</name></author><author><name sortKey="Winthrop, A L" uniqKey="Winthrop A">A.L. Winthrop</name></author><author><name sortKey="Schoeller, D A" uniqKey="Schoeller D">D.A. Schoeller</name></author><author><name sortKey="Swyer, P R" uniqKey="Swyer P">P.R. Swyer</name></author><author><name sortKey="Smith, J" uniqKey="Smith J">J. Smith</name></author><author><name sortKey="Filler, R M" uniqKey="Filler R">R.M. Filler</name></author><author><name sortKey="Heim, T" uniqKey="Heim T">T. Heim</name></author></analytic></biblStruct><biblStruct><analytic><author><name sortKey="Speakman, J R" uniqKey="Speakman J">J.R. Speakman</name></author></analytic></biblStruct></listBibl></div1></back></TEI><pmc article-type="research-article"><pmc-dir>properties open_access</pmc-dir>
<front><journal-meta><journal-id journal-id-type="nlm-ta">Cell Rep Med</journal-id><journal-id journal-id-type="iso-abbrev">Cell Rep Med</journal-id><journal-title-group><journal-title>Cell Reports Medicine</journal-title></journal-title-group><issn pub-type="epub">2666-3791</issn><publisher><publisher-name>Elsevier</publisher-name></publisher></journal-meta><article-meta><article-id pub-id-type="pmid">33665639</article-id><article-id pub-id-type="pmc">7897799</article-id><article-id pub-id-type="pii">S2666-3791(21)00014-8</article-id><article-id pub-id-type="doi">10.1016/j.xcrm.2021.100203</article-id><article-id pub-id-type="publisher-id">100203</article-id><article-categories><subj-group subj-group-type="heading"><subject>Article</subject></subj-group></article-categories><title-group><article-title>A standard calculation methodology for human doubly labeled water studies</article-title></title-group><contrib-group><contrib contrib-type="author" id="au1"><name><surname>Speakman</surname><given-names>John R.</given-names></name><email>j.speakman@abdn.ac.uk</email><xref rid="aff1" ref-type="aff">1</xref><xref rid="aff2" ref-type="aff">2</xref><xref rid="aff3" ref-type="aff">3</xref><xref rid="aff4" ref-type="aff">4</xref><xref rid="fn1" ref-type="fn">69</xref><xref rid="fn3" ref-type="fn">71</xref><xref rid="cor1" ref-type="corresp">∗</xref></contrib><contrib contrib-type="author" id="au2"><name><surname>Yamada</surname><given-names>Yosuke</given-names></name><email>yyamada831@gmail.com</email><xref rid="aff5" ref-type="aff">5</xref><xref rid="aff6" ref-type="aff">6</xref><xref rid="fn1" ref-type="fn">69</xref><xref rid="cor2" ref-type="corresp">∗∗</xref></contrib><contrib contrib-type="author" id="au3"><name><surname>Sagayama</surname><given-names>Hiroyuki</given-names></name><email>hiroyuki.sagayama.ka@u.tsukuba.ac.jp</email><xref rid="aff7" ref-type="aff">7</xref><xref rid="cor3" ref-type="corresp">∗∗∗</xref></contrib><contrib contrib-type="author" id="au4"><name><surname>Berman</surname><given-names>Elena S.F.</given-names></name><xref rid="aff8" ref-type="aff">8</xref></contrib><contrib contrib-type="author" id="au5"><name><surname>Ainslie</surname><given-names>Philip N.</given-names></name><xref rid="aff9" ref-type="aff">9</xref></contrib><contrib contrib-type="author" id="au6"><name><surname>Andersen</surname><given-names>Lene F.</given-names></name><xref rid="aff10" ref-type="aff">10</xref></contrib><contrib contrib-type="author" id="au7"><name><surname>Anderson</surname><given-names>Liam J.</given-names></name><xref rid="aff9" ref-type="aff">9</xref><xref rid="aff11" ref-type="aff">11</xref></contrib><contrib contrib-type="author" id="au8"><name><surname>Arab</surname><given-names>Lenore</given-names></name><xref rid="aff12" ref-type="aff">12</xref></contrib><contrib contrib-type="author" id="au9"><name><surname>Baddou</surname><given-names>Issaad</given-names></name><xref rid="aff13" ref-type="aff">13</xref></contrib><contrib contrib-type="author" id="au10"><name><surname>Bedu-Addo</surname><given-names>Kweku</given-names></name><xref rid="aff14" ref-type="aff">14</xref></contrib><contrib contrib-type="author" id="au11"><name><surname>Blaak</surname><given-names>Ellen E.</given-names></name><xref rid="aff15" ref-type="aff">15</xref></contrib><contrib contrib-type="author" id="au12"><name><surname>Blanc</surname><given-names>Stephane</given-names></name><xref rid="aff16" ref-type="aff">16</xref><xref rid="aff17" ref-type="aff">17</xref></contrib><contrib contrib-type="author" id="au13"><name><surname>Bonomi</surname><given-names>Alberto G.</given-names></name><xref rid="aff18" ref-type="aff">18</xref></contrib><contrib contrib-type="author" id="au14"><name><surname>Bouten</surname><given-names>Carlijn V.C.</given-names></name><xref rid="aff19" ref-type="aff">19</xref></contrib><contrib contrib-type="author" id="au15"><name><surname>Bovet</surname><given-names>Pascal</given-names></name><xref rid="aff20" ref-type="aff">20</xref></contrib><contrib contrib-type="author" id="au16"><name><surname>Buchowski</surname><given-names>Maciej S.</given-names></name><xref rid="aff21" ref-type="aff">21</xref></contrib><contrib contrib-type="author" id="au17"><name><surname>Butte</surname><given-names>Nancy F.</given-names></name><xref rid="aff22" ref-type="aff">22</xref></contrib><contrib contrib-type="author" id="au18"><name><surname>Camps</surname><given-names>Stefan G.J.A.</given-names></name><xref rid="aff15" ref-type="aff">15</xref></contrib><contrib contrib-type="author" id="au19"><name><surname>Close</surname><given-names>Graeme L.</given-names></name><xref rid="aff9" ref-type="aff">9</xref></contrib><contrib contrib-type="author" id="au20"><name><surname>Cooper</surname><given-names>Jamie A.</given-names></name><xref rid="aff16" ref-type="aff">16</xref></contrib><contrib contrib-type="author" id="au21"><name><surname>Creasy</surname><given-names>Seth A.</given-names></name><xref rid="aff23" ref-type="aff">23</xref></contrib><contrib contrib-type="author" id="au22"><name><surname>Das</surname><given-names>Sai Krupa</given-names></name><xref rid="aff24" ref-type="aff">24</xref></contrib><contrib contrib-type="author" id="au23"><name><surname>Cooper</surname><given-names>Richard</given-names></name><xref rid="aff25" ref-type="aff">25</xref></contrib><contrib contrib-type="author" id="au24"><name><surname>Dugas</surname><given-names>Lara R.</given-names></name><xref rid="aff25" ref-type="aff">25</xref></contrib><contrib contrib-type="author" id="au25"><name><surname>Ebbeling</surname><given-names>Cara B.</given-names></name><xref rid="aff26" ref-type="aff">26</xref></contrib><contrib contrib-type="author" id="au26"><name><surname>Ekelund</surname><given-names>Ulf</given-names></name><xref rid="aff27" ref-type="aff">27</xref></contrib><contrib contrib-type="author" id="au27"><name><surname>Entringer</surname><given-names>Sonja</given-names></name><xref rid="aff28" ref-type="aff">28</xref><xref rid="aff29" ref-type="aff">29</xref></contrib><contrib contrib-type="author" id="au28"><name><surname>Forrester</surname><given-names>Terrence</given-names></name><xref rid="aff30" ref-type="aff">30</xref></contrib><contrib contrib-type="author" id="au29"><name><surname>Fudge</surname><given-names>Barry W.</given-names></name><xref rid="aff31" ref-type="aff">31</xref></contrib><contrib contrib-type="author" id="au30"><name><surname>Goris</surname><given-names>Annelies H.</given-names></name><xref rid="aff15" ref-type="aff">15</xref></contrib><contrib contrib-type="author" id="au31"><name><surname>Gurven</surname><given-names>Michael</given-names></name><xref rid="aff32" ref-type="aff">32</xref></contrib><contrib contrib-type="author" id="au32"><name><surname>Hambly</surname><given-names>Catherine</given-names></name><xref rid="aff2" ref-type="aff">2</xref></contrib><contrib contrib-type="author" id="au33"><name><surname>El Hamdouchi</surname><given-names>Asmaa</given-names></name><xref rid="aff13" ref-type="aff">13</xref></contrib><contrib contrib-type="author" id="au34"><name><surname>Hoos</surname><given-names>Marije B.</given-names></name><xref rid="aff15" ref-type="aff">15</xref></contrib><contrib contrib-type="author" id="au35"><name><surname>Hu</surname><given-names>Sumei</given-names></name><xref rid="aff3" ref-type="aff">3</xref></contrib><contrib contrib-type="author" id="au36"><name><surname>Joonas</surname><given-names>Noorjehan</given-names></name><xref rid="aff33" ref-type="aff">33</xref></contrib><contrib contrib-type="author" id="au37"><name><surname>Joosen</surname><given-names>Annemiek M.</given-names></name><xref rid="aff15" ref-type="aff">15</xref></contrib><contrib contrib-type="author" id="au38"><name><surname>Katzmarzyk</surname><given-names>Peter</given-names></name><xref rid="aff34" ref-type="aff">34</xref></contrib><contrib contrib-type="author" id="au39"><name><surname>Kempen</surname><given-names>Kitty P.</given-names></name><xref rid="aff15" ref-type="aff">15</xref></contrib><contrib contrib-type="author" id="au40"><name><surname>Kimura</surname><given-names>Misaka</given-names></name><xref rid="aff6" ref-type="aff">6</xref></contrib><contrib contrib-type="author" id="au41"><name><surname>Kraus</surname><given-names>William E.</given-names></name><xref rid="aff35" ref-type="aff">35</xref></contrib><contrib contrib-type="author" id="au42"><name><surname>Kushner</surname><given-names>Robert F.</given-names></name><xref rid="aff36" ref-type="aff">36</xref></contrib><contrib contrib-type="author" id="au43"><name><surname>Lambert</surname><given-names>Estelle V.</given-names></name><xref rid="aff37" ref-type="aff">37</xref></contrib><contrib contrib-type="author" id="au44"><name><surname>Leonard</surname><given-names>William R.</given-names></name><xref rid="aff38" ref-type="aff">38</xref></contrib><contrib contrib-type="author" id="au45"><name><surname>Lessan</surname><given-names>Nader</given-names></name><xref rid="aff39" ref-type="aff">39</xref></contrib><contrib contrib-type="author" id="au46"><name><surname>Ludwig</surname><given-names>David S.</given-names></name><xref rid="aff26" ref-type="aff">26</xref></contrib><contrib contrib-type="author" id="au47"><name><surname>Martin</surname><given-names>Corby K.</given-names></name><xref rid="aff34" ref-type="aff">34</xref></contrib><contrib contrib-type="author" id="au48"><name><surname>Medin</surname><given-names>Anine C.</given-names></name><xref rid="aff10" ref-type="aff">10</xref><xref rid="aff40" ref-type="aff">40</xref></contrib><contrib contrib-type="author" id="au49"><name><surname>Meijer</surname><given-names>Erwin P.</given-names></name><xref rid="aff15" ref-type="aff">15</xref></contrib><contrib contrib-type="author" id="au50"><name><surname>Morehen</surname><given-names>James C.</given-names></name><xref rid="aff9" ref-type="aff">9</xref><xref rid="aff41" ref-type="aff">41</xref></contrib><contrib contrib-type="author" id="au51"><name><surname>Morton</surname><given-names>James P.</given-names></name><xref rid="aff9" ref-type="aff">9</xref></contrib><contrib contrib-type="author" id="au52"><name><surname>Neuhouser</surname><given-names>Marian L.</given-names></name><xref rid="aff42" ref-type="aff">42</xref></contrib><contrib contrib-type="author" id="au53"><name><surname>Nicklas</surname><given-names>Theresa A.</given-names></name><xref rid="aff22" ref-type="aff">22</xref></contrib><contrib contrib-type="author" id="au54"><name><surname>Ojiambo</surname><given-names>Robert M.</given-names></name><xref rid="aff43" ref-type="aff">43</xref><xref rid="aff44" ref-type="aff">44</xref></contrib><contrib contrib-type="author" id="au55"><name><surname>Pietiläinen</surname><given-names>Kirsi H.</given-names></name><xref rid="aff45" ref-type="aff">45</xref></contrib><contrib contrib-type="author" id="au56"><name><surname>Pitsiladis</surname><given-names>Yannis P.</given-names></name><xref rid="aff46" ref-type="aff">46</xref></contrib><contrib contrib-type="author" id="au57"><name><surname>Plange-Rhule</surname><given-names>Jacob</given-names></name><xref rid="aff47" ref-type="aff">47</xref><xref rid="fn2" ref-type="fn">70</xref></contrib><contrib contrib-type="author" id="au58"><name><surname>Plasqui</surname><given-names>Guy</given-names></name><xref rid="aff48" ref-type="aff">48</xref></contrib><contrib contrib-type="author" id="au59"><name><surname>Prentice</surname><given-names>Ross L.</given-names></name><xref rid="aff42" ref-type="aff">42</xref></contrib><contrib contrib-type="author" id="au60"><name><surname>Rabinovich</surname><given-names>Roberto A.</given-names></name><xref rid="aff49" ref-type="aff">49</xref></contrib><contrib contrib-type="author" id="au61"><name><surname>Racette</surname><given-names>Susan B.</given-names></name><xref rid="aff24" ref-type="aff">24</xref></contrib><contrib contrib-type="author" id="au62"><name><surname>Raichlen</surname><given-names>David A.</given-names></name><xref rid="aff50" ref-type="aff">50</xref></contrib><contrib contrib-type="author" id="au63"><name><surname>Ravussin</surname><given-names>Eric</given-names></name><xref rid="aff34" ref-type="aff">34</xref></contrib><contrib contrib-type="author" id="au64"><name><surname>Reynolds</surname><given-names>Rebecca M.</given-names></name><xref rid="aff51" ref-type="aff">51</xref></contrib><contrib contrib-type="author" id="au65"><name><surname>Roberts</surname><given-names>Susan B.</given-names></name><xref rid="aff24" ref-type="aff">24</xref></contrib><contrib contrib-type="author" id="au66"><name><surname>Schuit</surname><given-names>Albertine J.</given-names></name><xref rid="aff52" ref-type="aff">52</xref></contrib><contrib contrib-type="author" id="au67"><name><surname>Sjödin</surname><given-names>Anders M.</given-names></name><xref rid="aff53" ref-type="aff">53</xref></contrib><contrib contrib-type="author" id="au68"><name><surname>Stice</surname><given-names>Eric</given-names></name><xref rid="aff54" ref-type="aff">54</xref></contrib><contrib contrib-type="author" id="au69"><name><surname>Urlacher</surname><given-names>Samuel S.</given-names></name><xref rid="aff55" ref-type="aff">55</xref></contrib><contrib contrib-type="author" id="au70"><name><surname>Valenti</surname><given-names>Giulio</given-names></name><xref rid="aff15" ref-type="aff">15</xref></contrib><contrib contrib-type="author" id="au71"><name><surname>Van Etten</surname><given-names>Ludo M.</given-names></name><xref rid="aff15" ref-type="aff">15</xref></contrib><contrib contrib-type="author" id="au72"><name><surname>Van Mil</surname><given-names>Edgar A.</given-names></name><xref rid="aff56" ref-type="aff">56</xref></contrib><contrib contrib-type="author" id="au73"><name><surname>Wells</surname><given-names>Jonathan C.K.</given-names></name><xref rid="aff57" ref-type="aff">57</xref></contrib><contrib contrib-type="author" id="au74"><name><surname>Wilson</surname><given-names>George</given-names></name><xref rid="aff9" ref-type="aff">9</xref></contrib><contrib contrib-type="author" id="au75"><name><surname>Wood</surname><given-names>Brian M.</given-names></name><xref rid="aff58" ref-type="aff">58</xref><xref rid="aff59" ref-type="aff">59</xref></contrib><contrib contrib-type="author" id="au76"><name><surname>Yanovski</surname><given-names>Jack</given-names></name><xref rid="aff60" ref-type="aff">60</xref></contrib><contrib contrib-type="author" id="au77"><name><surname>Yoshida</surname><given-names>Tsukasa</given-names></name><xref rid="aff5" ref-type="aff">5</xref></contrib><contrib contrib-type="author" id="au78"><name><surname>Zhang</surname><given-names>Xueying</given-names></name><xref rid="aff1" ref-type="aff">1</xref><xref rid="aff2" ref-type="aff">2</xref></contrib><contrib contrib-type="author" id="au79"><name><surname>Murphy-Alford</surname><given-names>Alexia J.</given-names></name><xref rid="aff61" ref-type="aff">61</xref></contrib><contrib contrib-type="author" id="au80"><name><surname>Loechl</surname><given-names>Cornelia U.</given-names></name><xref rid="aff61" ref-type="aff">61</xref></contrib><contrib contrib-type="author" id="au81"><name><surname>Melanson</surname><given-names>Edward L.</given-names></name><xref rid="aff23" ref-type="aff">23</xref><xref rid="aff62" ref-type="aff">62</xref><xref rid="aff63" ref-type="aff">63</xref></contrib><contrib contrib-type="author" id="au82"><name><surname>Luke</surname><given-names>Amy H.</given-names></name><email>aluke@luc.edu</email><xref rid="aff64" ref-type="aff">64</xref><xref rid="cor4" ref-type="corresp">∗∗∗∗</xref></contrib><contrib contrib-type="author" id="au83"><name><surname>Pontzer</surname><given-names>Herman</given-names></name><email>pontzer@gmail.com</email><xref rid="aff65" ref-type="aff">65</xref><xref rid="aff66" ref-type="aff">66</xref><xref rid="cor5" ref-type="corresp">∗∗∗∗∗</xref></contrib><contrib contrib-type="author" id="au84"><name><surname>Rood</surname><given-names>Jennifer</given-names></name><email>jennifer.rood@pbrc.edu</email><xref rid="aff34" ref-type="aff">34</xref><xref rid="cor6" ref-type="corresp">∗∗∗∗∗∗</xref></contrib><contrib contrib-type="author" id="au85"><name><surname>Schoeller</surname><given-names>Dale A.</given-names></name><email>dschoell@nutrisci.wisc.edu</email><xref rid="aff67" ref-type="aff">67</xref><xref rid="cor7" ref-type="corresp">∗∗∗∗∗∗∗</xref></contrib><contrib contrib-type="author" id="au86"><name><surname>Westerterp</surname><given-names>Klaas R.</given-names></name><email>k.westerterp@maastrichtuniversity.nl</email><xref rid="aff68" ref-type="aff">68</xref><xref rid="cor8" ref-type="corresp">∗∗∗∗∗∗∗∗</xref></contrib><contrib contrib-type="author" id="au87"><name><surname>Wong</surname><given-names>William W.</given-names></name><email>wwong@bcm.edu</email><xref rid="aff22" ref-type="aff">22</xref><xref rid="cor9" ref-type="corresp">∗∗∗∗∗∗∗∗∗</xref></contrib><contrib contrib-type="author"><collab>the IAEA DLW database group</collab></contrib><aff id="aff1"><label>1</label>Center for Energy Metabolism and Reproduction, Shenzhen Institutes of Advanced Technology, Chinese Academy of Sciences, Shenzhen, China</aff><aff id="aff2"><label>2</label>Institute of Biological and Environmental Sciences, University of Aberdeen, Aberdeen, UK</aff><aff id="aff3"><label>3</label>State Key Laboratory of Molecular Developmental Biology, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing, China</aff><aff id="aff4"><label>4</label>CAS Center of Excellence in Animal Evolution and Genetics, Kunming, China</aff><aff id="aff5"><label>5</label>National Institute of Health and Nutrition, National Institutes of Biomedical Innovation, Health and Nutrition, Tokyo, Japan</aff><aff id="aff6"><label>6</label>Institute for Active Health, Kyoto University of Advanced Science, Kyoto, Japan</aff><aff id="aff7"><label>7</label>Faculty of Health and Sport Sciences, University of Tsukuba, Ibaraki, Japan</aff><aff id="aff8"><label>8</label>Berman Scientific Consulting, Mountain View, CA, USA</aff><aff id="aff9"><label>9</label>Research Institute for Sport and Exercise Sciences, Liverpool John Moores University, Liverpool, UK</aff><aff id="aff10"><label>10</label>Department of Nutrition, Institute of Basic Medical Sciences, University of Oslo, 0317 Oslo, Norway</aff><aff id="aff11"><label>11</label>Crewe Alexandra Football Club, Crewe, UK</aff><aff id="aff12"><label>12</label>David Geffen School of Medicine, University of California, Los Angeles, Los Angeles, CA, USA</aff><aff id="aff13"><label>13</label>Unité Mixte de Recherche en Nutrition et Alimentation, CNESTEN- Université Ibn Tofail URAC39, Regional Designated Center of Nutrition Associated with AFRA/IAEA, Rabat, Morocco</aff><aff id="aff14"><label>14</label>Department of Physiology, Kwame Nkrumah University of Science and Technology, Kumasi, Ghana</aff><aff id="aff15"><label>15</label>Maastricht University, Maastricht, the Netherlands</aff><aff id="aff16"><label>16</label>Nutritional Sciences, University of Wisconsin, Madison, WI, USA</aff><aff id="aff17"><label>17</label>Institut Pluridisciplinaire Hubert Curien, CNRS Université de Strasbourg, UMR7178, Strasbourg, France</aff><aff id="aff18"><label>18</label>Phillips Research, Eindhoven, the Netherlands</aff><aff id="aff19"><label>19</label>Department of Biomedical Engineering and Institute for Complex Molecular Systems, Eindhoven University of Technology, Eindhoven, the Netherlands</aff><aff id="aff20"><label>20</label>Institute of Social and Preventive Medicine, Lausanne University Hospital, Lausanne, Switzerland</aff><aff id="aff21"><label>21</label>Division of Gastroenterology, Hepatology and Nutrition, Department of Medicine, Vanderbilt University, Nashville, TN, USA</aff><aff id="aff22"><label>22</label>Department of Pediatrics, Baylor College of Medicine, USDA/ARS Children’s Nutrition Research Center, Houston, TX, USA</aff><aff id="aff23"><label>23</label>Division of Endocrinology, Metabolism and Diabetes, University of Colorado Anschulz Medical Campus, Aurora, CO, USA</aff><aff id="aff24"><label>24</label>Friedman School of Nutrition Science and Policy, Tufts University, 150 Harrison Avenue, Boston, MA, USA</aff><aff id="aff25"><label>25</label>Department of Public Health Sciences, Parkinson School of Health Sciences and Public Health, Loyola University, Maywood, IL, USA</aff><aff id="aff26"><label>26</label>Boston Children’s Hospital, Boston, MA, USA</aff><aff id="aff27"><label>27</label>Department of Sport Medicine, Norwegian School of Sport Sciences, Oslo, Norway</aff><aff id="aff28"><label>28</label>Charité – Universitätsmedizin Berlin, corporate member of Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health (BIH), Institute of Medical Psychology, Berlin, Germany</aff><aff id="aff29"><label>29</label>University of California, Irvine, Irvine, CA, USA</aff><aff id="aff30"><label>30</label>Solutions for Developing Countries, University of the West Indies, Mona, Kingston, Jamaica</aff><aff id="aff31"><label>31</label>University of Glasgow, Glasgow, UK</aff><aff id="aff32"><label>32</label>Department of Anthropology, University of California, Santa Barbara, Santa Barbara, CA, USA</aff><aff id="aff33"><label>33</label>Central Health Laboratory, Ministry of Health and Wellness, Port Louis, Mauritius</aff><aff id="aff34"><label>34</label>Pennington Biomedical Research Center, Baton Rouge, LA, USA</aff><aff id="aff35"><label>35</label>Department of Medicine, Duke University, Durham, NC, USA</aff><aff id="aff36"><label>36</label>Northwestern University, Chicago, IL, USA</aff><aff id="aff37"><label>37</label>Research Unit for Exercise Science and Sports Medicine, University of Cape Town, Cape Town, South Africa</aff><aff id="aff38"><label>38</label>Department of Anthropology, Northwestern University, Evanston, IL, USA</aff><aff id="aff39"><label>39</label>Imperial College London Diabetes Centre, Imperial College London, London, UK</aff><aff id="aff40"><label>40</label>Department of Nutrition and Public Health, Faculty of Health and Sport Sciences, University of Agder, 4630 Kristiansand, Norway</aff><aff id="aff41"><label>41</label>The FA Group, Burton-Upon-Trent, Staffordshire, UK</aff><aff id="aff42"><label>42</label>Division of Public Health Sciences, Fred Hutchinson Cancer Research Center and School of Public Health, University of Washington, Seattle, WA, USA</aff><aff id="aff43"><label>43</label>Moi University, Eldoret, Kenya</aff><aff id="aff44"><label>44</label>University of Global Health Equity, Kigali, Rwanda</aff><aff id="aff45"><label>45</label>Helsinki University Central Hospital, Helsinki, Finland</aff><aff id="aff46"><label>46</label>University of Brighton, Eastbourne, UK</aff><aff id="aff47"><label>47</label>Department of Physiology, Kwame Nkrumah University of Science and Technology, Kumasi, Ghana</aff><aff id="aff48"><label>48</label>Department of Nutrition and Movement Sciences, Maastricht University, Maastricht, the Netherlands</aff><aff id="aff49"><label>49</label>University of Edinburgh, Edinburgh, UK</aff><aff id="aff50"><label>50</label>Biological Sciences and Anthropology, University of Southern California, Los Angeles, CA, USA</aff><aff id="aff51"><label>51</label>Centre for Cardiovascular Sciences, Queen’s Medical Research Institute, University of Edinburgh, Edinburgh, UK</aff><aff id="aff52"><label>52</label>University of Tilburg, Tilburg, the Netherlands</aff><aff id="aff53"><label>53</label>Department of Nutrition, Exercise and Sports, Copenhagen University, Copenhagen, Denmark</aff><aff id="aff54"><label>54</label>Stanford University, Stanford, CA, USA</aff><aff id="aff55"><label>55</label>Department of Anthropology, Baylor University, Waco, TX, USA</aff><aff id="aff56"><label>56</label>Maastricht and Lifestyle Medicine Center for Children, Jeroen Bosch Hospital’s-Hertogenbosch, Maastricht University, Maastricht, the Netherlands</aff><aff id="aff57"><label>57</label>Population, Policy and Practice Research and Teaching Department, UCL Great Ormond Street Institute of Child Health, London, UK</aff><aff id="aff58"><label>58</label>University of California, Los Angeles, Los Angeles, CA, USA</aff><aff id="aff59"><label>59</label>Department of Human Behavior, Ecology, and Culture, Max Planck Institute for Evolutionary Anthropology, Leipzig, Germany</aff><aff id="aff60"><label>60</label>Growth and Obesity, Division of Intramural Research, NIH, Bethesda, MD, USA</aff><aff id="aff61"><label>61</label>Nutritional and Health Related Environmental Studies Section, Division of Human Health, International Atomic Energy Agency, Vienna, Austria</aff><aff id="aff62"><label>62</label>Eastern Colorado VA Geriatric Research, Education and Clinical Center, Aurora, CO, USA</aff><aff id="aff63"><label>63</label>Division of Geriatrics, University of Colorado Anschutz Medical Campus, Aurora, CO, USA</aff><aff id="aff64"><label>64</label>Division of Epidemiology, Department of Public Health Sciences, Loyola University School of Medicine, Maywood, IL, USA</aff><aff id="aff65"><label>65</label>Evolutionary Anthropology, Duke University, Durham, NC, USA</aff><aff id="aff66"><label>66</label>Duke Global Health Institute, Duke University, Durham, NC, USA</aff><aff id="aff67"><label>67</label>Biotech Center and Nutritional Sciences, University of Wisconsin, Madison, WI, USA</aff><aff id="aff68"><label>68</label>School of Nutrition and Translational Research in Metabolism, University of Maastricht, Maastricht, the Netherlands</aff></contrib-group><author-notes><corresp id="cor1"><label>∗</label>Corresponding author <email>j.speakman@abdn.ac.uk</email></corresp><corresp id="cor2"><label>∗∗</label>Corresponding author <email>yyamada831@gmail.com</email></corresp><corresp id="cor3"><label>∗∗∗</label>Corresponding author <email>hiroyuki.sagayama.ka@u.tsukuba.ac.jp</email></corresp><corresp id="cor4"><label>∗∗∗∗</label>Corresponding author <email>aluke@luc.edu</email></corresp><corresp id="cor5"><label>∗∗∗∗∗</label>Corresponding author <email>pontzer@gmail.com</email></corresp><corresp id="cor6"><label>∗∗∗∗∗∗</label>Corresponding author <email>jennifer.rood@pbrc.edu</email></corresp><corresp id="cor7"><label>∗∗∗∗∗∗∗</label>Corresponding author <email>dschoell@nutrisci.wisc.edu</email></corresp><corresp id="cor8"><label>∗∗∗∗∗∗∗∗</label>Corresponding author <email>k.westerterp@maastrichtuniversity.nl</email></corresp><corresp id="cor9"><label>∗∗∗∗∗∗∗∗∗</label>Corresponding author <email>wwong@bcm.edu</email></corresp><fn id="fn1"><label>69</label><p id="ntpara0010">These authors contributed equally</p></fn><fn id="fn2"><label>70</label><p id="ntpara0015">Deceased</p></fn><fn id="fn3"><label>71</label><p id="ntpara0020">Lead contact</p></fn></author-notes><pub-date pub-type="pmc-release"><day>16</day><month>2</month><year>2021</year></pub-date><pmc-comment> PMC Release delay is 0 months and 0 days and was based on .</pmc-comment>
<pub-date pub-type="collection"><day>16</day><month>2</month><year>2021</year></pub-date><pub-date pub-type="epub"><day>16</day><month>2</month><year>2021</year></pub-date><volume>2</volume><issue>2</issue><elocation-id>100203</elocation-id><history><date date-type="received"><day>29</day><month>6</month><year>2020</year></date><date date-type="rev-recd"><day>16</day><month>9</month><year>2020</year></date><date date-type="accepted"><day>20</day><month>1</month><year>2021</year></date></history><permissions><copyright-statement>© 2021 The Authors</copyright-statement><copyright-year>2021</copyright-year><license license-type="CC BY" xlink:href="http://creativecommons.org/licenses/by/4.0/"><license-p>This is an open access article under the CC BY license (http://creativecommons.org/licenses/by/4.0/).</license-p></license></permissions><abstract id="abs0010"><title>Summary</title><p>The doubly labeled water (DLW) method measures total energy expenditure (TEE) in free-living subjects. Several equations are used to convert isotopic data into TEE. Using the International Atomic Energy Agency (IAEA) DLW database (5,756 measurements of adults and children), we show considerable variability is introduced by different equations. The estimated rCO<sub>2</sub> is sensitive to the dilution space ratio (DSR) of the two isotopes. Based on performance in validation studies, we propose a new equation based on a new estimate of the mean DSR. The DSR is lower at low body masses (<10 kg). Using data for 1,021 babies and infants, we show that the DSR varies non-linearly with body mass between 0 and 10 kg. Using this relationship to predict DSR from weight provides an equation for rCO<sub>2</sub> over this size range that agrees well with indirect calorimetry (average difference 0.64%; SD = 12.2%). We propose adoption of these equations in future studies.</p></abstract><abstract abstract-type="graphical" id="abs0015"><title>Graphical Abstract</title><fig id="undfig1" position="anchor"><graphic xlink:href="fx1"></graphic></fig></abstract><abstract abstract-type="author-highlights" id="abs0020"><title>Highlights</title><p><list list-type="simple" id="ulist0010"><list-item id="u0010"><p id="p0010">5,756 doubly labeled water (DLW) measures highlight variation from calculation equation</p></list-item><list-item id="u0015"><p id="p0015">We derive here new equations for calculating CO<sub>2</sub> production when using DLW</p></list-item><list-item id="u0020"><p id="p0020">These equations outperform previous equations in validation studies</p></list-item><list-item id="u0025"><p id="p0025">We recommend these equations should be adopted in future studies using DLW in humans</p></list-item></list></p></abstract><abstract abstract-type="teaser" id="abs0025"><p>Speakman et al. use a large database of doubly labeled water measurements to show the choice of equation for the calculation of energy expenditure introduces significant variation into the final estimate. They then derive new equations that outperform previous equations in validation studies against chamber calorimetry.</p></abstract><kwd-group id="kwrds0010"><title>Keywords</title><kwd>total energy expenditure</kwd><kwd>free-living</kwd><kwd>validation</kwd><kwd>doubly labeled water</kwd></kwd-group></article-meta><notes><p id="misc0010">Published: February 16, 2021</p></notes></front><body><sec id="sec1"><title>Introduction</title><p id="p0030">The doubly labeled water (DLW) method<xref rid="bib1" ref-type="bibr"><sup>1</sup></xref><sup>,</sup><xref rid="bib2" ref-type="bibr"><sup>2</sup></xref> is an isotope-based technique for measuring rCO<sub>2</sub> in free-living animals and humans.<xref rid="bib3" ref-type="bibr"><sup>3</sup></xref> The method is based on the observation that the oxygen in respiratory CO<sub>2</sub> is in complete isotopic equilibrium with the oxygen in body water. Hence, isotopically labeled oxygen introduced into the body water is eliminated as both water and CO<sub>2</sub>. In contrast, a simultaneously introduced label of hydrogen (such as deuterium) will be predominantly eliminated as water. The difference in elimination rates of the two isotopes (hence “doubly labeled” water) gives a measure of rCO<sub>2</sub>. If the respiratory quotient (RQ) (the ratio of CO<sub>2</sub> production to O<sub>2</sub> consumption) or food quotient (FQ) (the proportions of fat, protein, and carbohydrate in the diet) is known, the rCO<sub>2</sub> can be converted to estimated energy expenditure using standard equations.</p><p id="p0035">The prohibitive cost of the isotopes limited early use of the method to small animals.<xref rid="bib4" ref-type="bibr"><sup>4</sup></xref> Advances in mass spectrometry, which reduced the required dose, along with the declining cost of the isotopes enabled the first applications to humans in the early 1980s.<xref rid="bib5" ref-type="bibr">5</xref>, <xref rid="bib6" ref-type="bibr">6</xref>, <xref rid="bib7" ref-type="bibr">7</xref> Since then, use of the method has grown steadily with currently approximately 100 papers published using the method annually.<xref rid="bib8" ref-type="bibr"><sup>8</sup></xref> However, costs continue to keep sample sizes in most studies relatively small (typically less than 50 individuals). There has been an impetus in the last few years, therefore, to combine data across studies to extend or modify conclusions about the main factors driving energy demands.<xref rid="bib9" ref-type="bibr"><sup>9</sup></xref><sup>,</sup><xref rid="bib10" ref-type="bibr"><sup>10</sup></xref></p><p id="p0040">The simple description of the technique above belies a great deal of complexity in its theoretical basis.<xref rid="bib2" ref-type="bibr"><sup>2</sup></xref><sup>,</sup><xref rid="bib3" ref-type="bibr"><sup>3</sup></xref><sup>,</sup><xref rid="bib10" ref-type="bibr"><sup>10</sup></xref><sup>,</sup><xref rid="bib11" ref-type="bibr"><sup>11</sup></xref> For example, isotopes fractionate as they leave the body, so that lighter isotopes are preferentially lost. This effect needs to be accounted for in the calculation. Another issue is that the isotopes are assumed to be turning over in the body water pool. The body water pool can be measured from the dilution space of the isotopic doses, but the dilution space of 18oxygen (N<sub>O</sub>) differs from that of deuterium (N<sub>d</sub>), and both differ slightly from the total body water (TBW). The oxygen dilution space is about 1% larger than the TBW although the hydrogen dilution space is about 4% larger. This difference stems primarily from hydrogen in body water exchanging with labile hydrogen in proteins and other organic molecules in the body. The relationship between N<sub>d</sub>, N<sub>o</sub>, and TBW affect the calculation of rCO<sub>2</sub>, and thus, the dilution space ratio (DSR), which is equal to N<sub>d</sub>/ N<sub>O</sub>, turns out to be a critical parameter in DLW studies.</p><p id="p0045">A final complexity that must be considered is the choice of equation used to calculate rCO<sub>2</sub>. Although there are only four basic parameters that are derived from the isotope elimination measurements (the two elimination constants for 18oxygen [k<sub>O</sub>] and deuterium [k<sub>d</sub>] and the two isotope dilution spaces [N<sub>O</sub> and N<sub>d</sub>]), the best approach combining these parameters to estimate rCO<sub>2</sub> was a matter of considerable debate throughout the late 1980s and 1990s.<xref rid="bib3" ref-type="bibr"><sup>3</sup></xref> These discussions never reached a broad consensus, and hence, different studies have subsequently combined the parameters in slightly different ways. Such differences are largely irrelevant if the objective is to compare groups within a single study. However, if absolute values of energy demand are required, such as might be needed if the DLW method is being utilized as a validation method (for example, for measurements of habitual food intake), to compare total energy expenditure (TEE) across cultures and lifestyles, or if comparisons are made to previous studies, the differences in calculation could be significant. The consequences of this variability have never been thoroughly evaluated but have been assumed to be small relative to the biological variation under study. In this paper, we evaluate the impact of using different equations and derive new standard equations based on performance in validation studies for use in future studies. We address this issue first for studies of children, adolescents, and adults and then for studies of small infants and babies.</p></sec><sec id="sec2"><title>Results and discussion</title><sec id="sec2.1"><title>Children, adolescents, and adults</title><p id="p0050">We have compiled in the International Atomic Energy Agency (IAEA) DLW database (v3.1; <ext-link ext-link-type="uri" xlink:href="https://www.dlwdatabase.org" id="intref0010">https://www.dlwdatabase.org</ext-link>) individual data from 119 DLW studies comprising a total of 6,246 measurements of individuals aged 2–96 years.<xref rid="bib8" ref-type="bibr"><sup>8</sup></xref> For 5,756 of these measurements, we have access to the individual values of k<sub>o</sub>, k<sub>d</sub>, N<sub>o</sub>, and N<sub>d</sub>, allowing us to recalculate rCO<sub>2</sub> using a single equation, and compare these to the original estimates made using a diversity of calculation methods. To choose the best equation for the common calculation, we compiled data from six validation studies involving 61 adult humans, where rCO<sub>2</sub> by DLW has been compared with simultaneous indirect calorimetry (<xref rid="tbl1" ref-type="table">Table 1</xref>).<xref rid="bib12" ref-type="bibr">12</xref>, <xref rid="bib13" ref-type="bibr">13</xref>, <xref rid="bib14" ref-type="bibr">14</xref>, <xref rid="bib15" ref-type="bibr">15</xref>, <xref rid="bib16" ref-type="bibr">16</xref>, <xref rid="bib17" ref-type="bibr">17</xref> This comparison yielded three equations where rCO<sub>2</sub> did not differ significantly from the chamber values (<xref rid="tbl1" ref-type="table">Table 1</xref>).<xref rid="bib3" ref-type="bibr"><sup>3</sup></xref><sup>,</sup><xref rid="bib18" ref-type="bibr">18</xref>, <xref rid="bib19" ref-type="bibr">19</xref>, <xref rid="bib20" ref-type="bibr">20</xref>, <xref rid="bib21" ref-type="bibr">21</xref>, <xref rid="bib22" ref-type="bibr">22</xref> The equation with the lowest average deviation was derived from an analysis of dilution space ratios in Sagayama et al.<xref rid="bib20" ref-type="bibr"><sup>20</sup></xref> Using the average dilution space ratio of 1.036, we modified the original Equation A6 proposed by Schoeller et al.<xref rid="bib15" ref-type="bibr"><sup>15</sup></xref> and derived a new equation here, for which the average discrepancy between the DLW estimates of rCO<sub>2</sub> and simultaneous chamber estimates was −0.4% (SD = 7.6%; <xref rid="tbl1" ref-type="table">Table 1</xref>).<table-wrap position="float" id="tbl1"><label>Table 1</label><caption><p>Validation results for carbon dioxide production (rCO<sub>2</sub>) for 61 individuals measured using the doubly labeled water method simultaneous to chamber calorimetry</p></caption><table frame="hsides" rules="groups"><thead><tr><th>Source<hr></hr></th><th>ID<hr></hr></th><th>BM<hr></hr></th><th>VCO2 IC<hr></hr></th><th colspan="2">Schoeller 1988<hr></hr></th><th colspan="2">Racette et al., 1994<hr></hr></th><th colspan="2">Sagayama et al., 2016<hr></hr></th><th colspan="2">Speakman 1997<hr></hr></th><th colspan="2">Speakman et al., 1993<hr></hr></th><th colspan="2">Coward and Prentice 1985<hr></hr></th></tr><tr><th></th><th></th><th>kg</th><th>L/d</th><th>L/d</th><th>%</th><th>L/d</th><th>%</th><th>L/d</th><th>%</th><th>L/d</th><th>%</th><th>L/d</th><th>%</th><th>L/d</th><th>%</th></tr></thead><tbody><tr><td>Schoeller and Webb<xref rid="bib12" ref-type="bibr"><sup>12</sup></xref></td><td>M17</td><td>67.5</td><td>566.7</td><td>579.3</td><td>2.2</td><td>571.4</td><td>0.8</td><td>567.5</td><td>0.1</td><td></td><td></td><td>548.9</td><td>−3.2</td><td></td><td></td></tr><tr><td></td><td>F25</td><td>72.0</td><td>439.0</td><td>448.9</td><td>2.2</td><td>440.4</td><td>0.3</td><td>436.2</td><td>−0.6</td><td></td><td></td><td>417.9</td><td>−4.8</td><td></td><td></td></tr><tr><td></td><td>F27</td><td>57.1</td><td>436.8</td><td>382.1</td><td>−12.5</td><td>374.2</td><td>−14.3</td><td>370.3</td><td>−15.2</td><td></td><td></td><td>353.6</td><td>−19.0</td><td></td><td></td></tr><tr><td></td><td>M28</td><td>67.5</td><td>611.5</td><td>608.2</td><td>−0.5</td><td>596.6</td><td>−2.4</td><td>590.9</td><td>−3.4</td><td></td><td></td><td>565.8</td><td>−7.5</td><td></td><td></td></tr><tr><td></td><td>M58</td><td>88.2</td><td>486.1</td><td>521.8</td><td>7.4</td><td>514.3</td><td>5.8</td><td>510.5</td><td>5.0</td><td></td><td></td><td>493.0</td><td>1.4</td><td></td><td></td></tr><tr><td>Westerterp et al.<xref rid="bib13" ref-type="bibr"><sup>13</sup></xref></td><td>1</td><td>73.2</td><td>508.0</td><td>495.0</td><td>−2.6</td><td>487.1</td><td>−4.1</td><td>483.2</td><td>−4.9</td><td></td><td></td><td>465.4</td><td>−8.4</td><td></td><td></td></tr><tr><td></td><td>2</td><td>77.9</td><td>479.0</td><td>506.5</td><td>5.7</td><td>498.2</td><td>4.0</td><td>494.2</td><td>3.2</td><td></td><td></td><td>475.8</td><td>−0.7</td><td></td><td></td></tr><tr><td></td><td>3</td><td>57.6</td><td>356.0</td><td>352.0</td><td>−1.1</td><td>346.5</td><td>−2.7</td><td>343.8</td><td>−3.4</td><td></td><td></td><td>331.4</td><td>−6.9</td><td></td><td></td></tr><tr><td></td><td>4</td><td>72.0</td><td>457.0</td><td>441.4</td><td>−3.4</td><td>435.5</td><td>−4.7</td><td>432.6</td><td>−5.3</td><td></td><td></td><td>418.6</td><td>−8.4</td><td></td><td></td></tr><tr><td></td><td>5</td><td>58.1</td><td>437.0</td><td>422.9</td><td>−3.2</td><td>414.3</td><td>−5.2</td><td>410.1</td><td>−6.2</td><td></td><td></td><td>391.8</td><td>−10.3</td><td></td><td></td></tr><tr><td></td><td>6A</td><td>75.6</td><td>894.0</td><td>919.0</td><td>2.8</td><td>907.5</td><td>1.5</td><td>901.9</td><td>0.9</td><td></td><td></td><td>874.1</td><td>−2.2</td><td></td><td></td></tr><tr><td></td><td>7A</td><td>64.7</td><td>818.0</td><td>931.9</td><td>13.9</td><td>920.6</td><td>12.5</td><td>915.1</td><td>11.9</td><td></td><td></td><td>887.7</td><td>8.5</td><td></td><td></td></tr><tr><td></td><td>8A</td><td>71.0</td><td>981.0</td><td>947.5</td><td>−3.4</td><td>934.2</td><td>−4.8</td><td>927.7</td><td>−5.4</td><td></td><td></td><td>896.6</td><td>−8.6</td><td></td><td></td></tr><tr><td></td><td>9A</td><td>77.9</td><td>1,104.0</td><td>1,085.9</td><td>−1.6</td><td>1,070.4</td><td>−3.0</td><td>1,062.8</td><td>−3.7</td><td></td><td></td><td>1,026.8</td><td>−7.0</td><td></td><td></td></tr><tr><td>Seale et al.<xref rid="bib14" ref-type="bibr"><sup>14</sup></xref></td><td>1</td><td>100.4</td><td>531.0</td><td>550.7</td><td>3.7</td><td>538.0</td><td>1.3</td><td>531.7</td><td>0.1</td><td></td><td></td><td>505.3</td><td>−4.8</td><td></td><td></td></tr><tr><td></td><td>2</td><td>50.3</td><td>392.0</td><td>407.4</td><td>3.9</td><td>398.5</td><td>1.7</td><td>394.2</td><td>0.6</td><td></td><td></td><td>375.5</td><td>−4.2</td><td></td><td></td></tr><tr><td></td><td>3</td><td>59.0</td><td>331.0</td><td>343.2</td><td>3.7</td><td>336.3</td><td>1.6</td><td>333.0</td><td>0.6</td><td></td><td></td><td>318.4</td><td>−3.8</td><td></td><td></td></tr><tr><td></td><td>4</td><td>52.6</td><td>451.0</td><td>442.1</td><td>−2.0</td><td>427.3</td><td>−5.3</td><td>420.1</td><td>−6.9</td><td></td><td></td><td>391.1</td><td>−13.3</td><td></td><td></td></tr><tr><td></td><td>5</td><td>82.7</td><td>530.0</td><td>545.9</td><td>3.0</td><td>535.0</td><td>0.9</td><td>529.7</td><td>−0.1</td><td></td><td></td><td>506.4</td><td>−4.5</td><td></td><td></td></tr><tr><td></td><td>6</td><td>86.2</td><td>550.0</td><td>545.2</td><td>−0.9</td><td>530.4</td><td>−3.6</td><td>523.1</td><td>−4.9</td><td></td><td></td><td>493.1</td><td>−10.3</td><td></td><td></td></tr><tr><td></td><td>7</td><td>87.4</td><td>515.0</td><td>531.0</td><td>3.1</td><td>522.2</td><td>1.4</td><td>517.9</td><td>0.6</td><td></td><td></td><td>498.2</td><td>−3.3</td><td></td><td></td></tr><tr><td></td><td>8</td><td>47.8</td><td>403.0</td><td>395.8</td><td>−1.8</td><td>383.8</td><td>−4.8</td><td>378.0</td><td>−6.2</td><td></td><td></td><td>354.2</td><td>−12.1</td><td></td><td></td></tr><tr><td></td><td>9</td><td>79.9</td><td>494.0</td><td>511.1</td><td>3.5</td><td>503.2</td><td>1.9</td><td>499.3</td><td>1.1</td><td></td><td></td><td>481.3</td><td>−2.6</td><td></td><td></td></tr><tr><td>Schoeller et al.<xref rid="bib15" ref-type="bibr"><sup>15</sup></xref></td><td>ID</td><td>75.3</td><td>559.0</td><td>570.6</td><td>2.1</td><td>564.5</td><td>1.0</td><td>561.1</td><td>0.4</td><td></td><td></td><td>543.4</td><td>−2.8</td><td></td><td></td></tr><tr><td></td><td>NM</td><td>75.6</td><td>614.0</td><td>598.5</td><td>−2.5</td><td>591.0</td><td>−3.7</td><td>587.3</td><td>−4.4</td><td></td><td></td><td>568.5</td><td>−7.4</td><td></td><td></td></tr><tr><td></td><td>ED</td><td>76.3</td><td>633.0</td><td>591.5</td><td>−6.6</td><td>582.8</td><td>−7.9</td><td>578.4</td><td>−8.6</td><td></td><td></td><td>557.9</td><td>−11.9</td><td></td><td></td></tr><tr><td></td><td>MK</td><td>69.5</td><td>541.0</td><td>543.6</td><td>0.5</td><td>531.5</td><td>−1.8</td><td>526.5</td><td>−2.7</td><td>537.2</td><td>−0.7</td><td>506.1</td><td>−6.5</td><td>529.3</td><td>−2.2</td></tr><tr><td></td><td>JD</td><td>64.1</td><td>504.0</td><td>440.0</td><td>−12.7</td><td>432.7</td><td>−14.1</td><td>428.8</td><td>−14.9</td><td>438.3</td><td>−13.0</td><td>410.7</td><td>−18.5</td><td>340.5</td><td>−32.4</td></tr><tr><td></td><td>DM</td><td>73.3</td><td>566.0</td><td>650.1</td><td>14.9</td><td>640.7</td><td>13.2</td><td>636.9</td><td>12.5</td><td>659.6</td><td>16.5</td><td>619.8</td><td>9.5</td><td>581.6</td><td>2.8</td></tr><tr><td></td><td>AB</td><td>56.7</td><td>468.0</td><td>460.2</td><td>−1.7</td><td>452.6</td><td>−3.3</td><td>449.5</td><td>−4.0</td><td>463.3</td><td>−1.0</td><td>435.4</td><td>−7.0</td><td>443.6</td><td>−5.2</td></tr><tr><td></td><td>LC</td><td>85.2</td><td>626.0</td><td>656.6</td><td>4.9</td><td>643.1</td><td>2.7</td><td>637.9</td><td>1.9</td><td>654.6</td><td>4.6</td><td>616.8</td><td>−1.5</td><td>632.3</td><td>1.0</td></tr><tr><td></td><td>DP</td><td>63.1</td><td>529.0</td><td>519.6</td><td>−1.8</td><td>512.0</td><td>−3.2</td><td>508.7</td><td>−3.8</td><td>525.5</td><td>−0.7</td><td>493.4</td><td>−6.7</td><td>515.4</td><td>−2.6</td></tr><tr><td>Ravussin et al.<xref rid="bib16" ref-type="bibr"><sup>16</sup></xref></td><td>1</td><td>124.6</td><td>499.0</td><td>462.1</td><td>−7.4</td><td>452.6</td><td>−9.3</td><td>448.6</td><td>−10.1</td><td>415.0</td><td>−16.8</td><td>432.0</td><td>−13.4</td><td>398.7</td><td>−20.1</td></tr><tr><td></td><td>2</td><td>61.4</td><td>356.0</td><td>413.3</td><td>16.1</td><td>404.7</td><td>13.7</td><td>401.2</td><td>12.7</td><td>370.9</td><td>4.2</td><td>386.2</td><td>8.5</td><td>318.8</td><td>−10.5</td></tr><tr><td></td><td>3</td><td>137.6</td><td>535.0</td><td>556.6</td><td>4.0</td><td>543.2</td><td>1.5</td><td>537.5</td><td>0.5</td><td>483.4</td><td>−9.7</td><td>514.2</td><td>−3.9</td><td>443.9</td><td>−17.0</td></tr><tr><td></td><td>4</td><td>80.9</td><td>393.0</td><td>503.8</td><td>28.2</td><td>489.9</td><td>24.7</td><td>483.9</td><td>23.1</td><td>422.8</td><td>7.6</td><td>459.9</td><td>17.0</td><td>321.3</td><td>−18.2</td></tr><tr><td></td><td>5</td><td>101.8</td><td>370.0</td><td>402.3</td><td>8.7</td><td>393.6</td><td>6.4</td><td>389.9</td><td>5.4</td><td>357.8</td><td>−3.3</td><td>374.8</td><td>1.3</td><td>318.5</td><td>−13.9</td></tr><tr><td></td><td>6</td><td>139.9</td><td>424.0</td><td>427.7</td><td>0.9</td><td>420.1</td><td>−0.9</td><td>416.9</td><td>−1.7</td><td>393.7</td><td>−7.1</td><td>403.4</td><td>−4.9</td><td>384.7</td><td>−9.3</td></tr><tr><td></td><td>7</td><td>190.9</td><td>711.0</td><td>733.7</td><td>3.2</td><td>718.0</td><td>1.0</td><td>711.4</td><td>0.0</td><td>653.8</td><td>−8.0</td><td>683.9</td><td>−3.8</td><td>541.5</td><td>−23.8</td></tr><tr><td></td><td>8</td><td>95.8</td><td>480.0</td><td>590.9</td><td>23.1</td><td>575.0</td><td>19.8</td><td>568.0</td><td>18.3</td><td>498.8</td><td>3.9</td><td>540.4</td><td>12.6</td><td>396.9</td><td>−17.3</td></tr><tr><td></td><td>9</td><td>151.5</td><td>672.0</td><td>683.3</td><td>1.7</td><td>662.0</td><td>−1.5</td><td>652.5</td><td>−2.9</td><td>551.9</td><td>−17.9</td><td>615.6</td><td>−8.4</td><td>510.6</td><td>−24.0</td></tr><tr><td></td><td>10</td><td>68.6</td><td>373.0</td><td>406.3</td><td>8.9</td><td>390.4</td><td>4.7</td><td>383.1</td><td>2.7</td><td>300.2</td><td>−19.5</td><td>355.6</td><td>−4.7</td><td>277.5</td><td>−25.6</td></tr><tr><td></td><td>11</td><td>69.4</td><td>332.0</td><td>354.2</td><td>6.7</td><td>344.4</td><td>3.7</td><td>340.0</td><td>2.4</td><td>296.4</td><td>−10.7</td><td>323.0</td><td>−2.7</td><td>234.7</td><td>−29.3</td></tr><tr><td></td><td>12</td><td>80.1</td><td>403.0</td><td>468.0</td><td>16.1</td><td>457.6</td><td>13.5</td><td>453.2</td><td>12.5</td><td>413.8</td><td>2.7</td><td>435.1</td><td>8.0</td><td>361.5</td><td>−10.3</td></tr><tr><td>Melanson et al.<xref rid="bib17" ref-type="bibr"><sup>17</sup></xref></td><td>1</td><td>63.0</td><td>310.6</td><td>299.4</td><td>−3.6</td><td>291.7</td><td>−6.1</td><td>286.6</td><td>−7.7</td><td>280.0</td><td>−9.8</td><td>263.8</td><td>−15.1</td><td>285.1</td><td>−8.2</td></tr><tr><td></td><td>2</td><td>82.8</td><td>457.4</td><td>447.0</td><td>−2.3</td><td>440.4</td><td>−3.7</td><td>436.6</td><td>−4.6</td><td>445.0</td><td>−2.7</td><td>418.1</td><td>−8.6</td><td>420.4</td><td>−8.1</td></tr><tr><td></td><td>3</td><td>74.8</td><td>455.8</td><td>476.2</td><td>4.5</td><td>467.5</td><td>2.6</td><td>463.5</td><td>1.7</td><td>474.2</td><td>4.0</td><td>445.5</td><td>−2.3</td><td>429.6</td><td>−5.7</td></tr><tr><td></td><td>4</td><td>61.0</td><td>346.8</td><td>361.6</td><td>4.3</td><td>354.6</td><td>2.2</td><td>351.0</td><td>1.2</td><td>356.6</td><td>2.8</td><td>335.2</td><td>−3.4</td><td>324.2</td><td>−6.5</td></tr><tr><td></td><td>5</td><td>93.8</td><td>471.3</td><td>465.4</td><td>−1.2</td><td>454.0</td><td>−3.7</td><td>449.0</td><td>−4.7</td><td>456.0</td><td>−3.2</td><td>428.7</td><td>−9.0</td><td>389.9</td><td>−17.3</td></tr><tr><td></td><td>6</td><td>48.9</td><td>293.4</td><td>325.6</td><td>11.0</td><td>318.5</td><td>8.6</td><td>314.6</td><td>7.2</td><td>316.0</td><td>7.7</td><td>297.2</td><td>1.3</td><td>291.0</td><td>−0.8</td></tr><tr><td></td><td>7</td><td>53.3</td><td>349.9</td><td>352.7</td><td>0.8</td><td>343.6</td><td>−1.8</td><td>339.1</td><td>−3.1</td><td>340.1</td><td>−2.8</td><td>320.0</td><td>−8.5</td><td>298.1</td><td>−14.8</td></tr><tr><td></td><td>8</td><td>91.5</td><td>444.2</td><td>447.8</td><td>0.8</td><td>437.8</td><td>−1.4</td><td>433.7</td><td>−2.4</td><td>444.1</td><td>0.0</td><td>417.3</td><td>−6.1</td><td>385.0</td><td>−13.3</td></tr><tr><td></td><td>9</td><td>71.6</td><td>442.8</td><td>429.6</td><td>−3.0</td><td>418.0</td><td>−5.6</td><td>412.6</td><td>−6.8</td><td>415.5</td><td>−6.2</td><td>390.9</td><td>−11.7</td><td>351.9</td><td>−20.5</td></tr><tr><td></td><td>10</td><td>111.6</td><td>514.4</td><td>550.8</td><td>7.1</td><td>539.5</td><td>4.9</td><td>533.7</td><td>3.7</td><td>540.7</td><td>5.1</td><td>508.3</td><td>−1.2</td><td>489.8</td><td>−4.8</td></tr><tr><td></td><td>11</td><td>95.0</td><td>437.1</td><td>540.4</td><td>23.6</td><td>526.7</td><td>20.5</td><td>519.7</td><td>18.9</td><td>520.7</td><td>19.1</td><td>489.9</td><td>12.1</td><td>461.6</td><td>5.6</td></tr><tr><td></td><td>12</td><td>115.0</td><td>423.1</td><td>470.5</td><td>11.2</td><td>461.6</td><td>9.1</td><td>457.5</td><td>8.1</td><td>468.0</td><td>10.6</td><td>439.7</td><td>3.9</td><td>421.2</td><td>−0.5</td></tr><tr><td></td><td>13</td><td>101.4</td><td>433.7</td><td>433.1</td><td>−0.1</td><td>423.7</td><td>−2.3</td><td>419.3</td><td>−3.3</td><td>426.5</td><td>−1.7</td><td>400.9</td><td>−7.6</td><td>376.7</td><td>−13.2</td></tr><tr><td></td><td>14</td><td>73.9</td><td>473.4</td><td>443.0</td><td>−6.4</td><td>428.9</td><td>−9.4</td><td>422.8</td><td>−10.7</td><td>424.5</td><td>−10.3</td><td>399.5</td><td>−15.6</td><td>335.1</td><td>−29.2</td></tr><tr><td></td><td>15</td><td>72.0</td><td>394.0</td><td>353.6</td><td>−10.3</td><td>344.8</td><td>−12.5</td><td>340.8</td><td>−13.5</td><td>344.8</td><td>−12.5</td><td>324.2</td><td>−17.7</td><td>296.4</td><td>−24.8</td></tr><tr><td></td><td>16</td><td>61.7</td><td>353.8</td><td>345.7</td><td>−2.3</td><td>335.6</td><td>−5.2</td><td>331.0</td><td>−6.5</td><td>332.3</td><td>−6.1</td><td>312.6</td><td>−11.6</td><td>274.7</td><td>−22.4</td></tr><tr><td></td><td>17</td><td>69.6</td><td>387.9</td><td>402.2</td><td>3.7</td><td>393.9</td><td>1.5</td><td>389.9</td><td>0.5</td><td>396.5</td><td>2.2</td><td>372.6</td><td>−3.9</td><td>354.4</td><td>−8.6</td></tr><tr><td>All subjects</td><td>N</td><td>61</td><td>61</td><td>61</td><td>61</td><td>61</td><td>61</td><td>61</td><td>61</td><td>35</td><td>35</td><td>61</td><td>61</td><td>35</td><td>35</td></tr><tr><td></td><td>mean</td><td>80.5</td><td>497.52</td><td>509.71</td><td>2.74</td><td>499.49</td><td>0.60</td><td>494.69</td><td>−0.40</td><td>440.52</td><td>−2.08</td><td>473.96</td><td>−4.72</td><td>392.47</td><td>−12.89</td></tr><tr><td></td><td>SD</td><td>26.2</td><td>152.69</td><td>155.18</td><td>7.97</td><td>153.74</td><td>7.74</td><td>153.11</td><td>7.67</td><td>98.67</td><td>9.05</td><td>149.72</td><td>7.51</td><td>95.32</td><td>9.94</td></tr><tr><td></td><td>T</td><td></td><td></td><td></td><td>2.69</td><td></td><td>0.61</td><td></td><td>−0.4</td><td></td><td>1.36</td><td></td><td>−4.9</td><td></td><td>−7.7</td></tr><tr><td></td><td>P</td><td></td><td></td><td></td><td>0.009</td><td></td><td>0.55</td><td></td><td>0.68</td><td></td><td>0.18</td><td></td><td><0.001</td><td></td><td><0.001</td></tr></tbody></table><table-wrap-foot><fn><p>Source is the reference where the original validation data were published. ID is the ID from the original study. BM is the mean body mass of the individual in kg. rCO<sub>2</sub> IC is the indirect calorimetry estimate of CO<sub>2</sub> production in liters per day. For each DLW equation, the original data were used to calculate rCO<sub>2</sub> and the % difference between these estimates and the chamber CO<sub>2</sub> production is calculated. At the bottom of the table, the summary statistics across all 61 individuals are shown. Schoeller 1988 refers to Equation A6 in Schoeller et al.<xref rid="bib15" ref-type="bibr"><sup>15</sup></xref> as modified in Schoeller.<xref rid="bib18" ref-type="bibr"><sup>18</sup></xref> Racette et al., 1994 refers to Equation A6 in Schoeller et al.<xref rid="bib15" ref-type="bibr"><sup>15</sup></xref> with the revised dilution space constant provided by Racette et al.<xref rid="bib19" ref-type="bibr"><sup>19</sup></xref> Sagayama et al., 2016 refers to Equation A6 in Schoeller et al.<xref rid="bib15" ref-type="bibr"><sup>15</sup></xref> with the revised dilution space constant provided by Sagayama et al.<xref rid="bib20" ref-type="bibr"><sup>20</sup></xref> and detailed here as <xref rid="fd1" ref-type="disp-formula">Equation 1</xref>. Speakman 1997 refers to Equation 17.41 in Speakman.<xref rid="bib3" ref-type="bibr"><sup>3</sup></xref> Speakman et al., 1993 refers to Equation 3 in Speakman et al.,<xref rid="bib21" ref-type="bibr"><sup>21</sup></xref> and Coward and Prentice 1985 refers to the two-pool equation in Coward and Prentice.<xref rid="bib22" ref-type="bibr"><sup>22</sup></xref> For some of the studies, N<sub>d</sub> was not available from the original validations. Because the equations by Speakman 1997 and Coward 1985 require individual estimates of N<sub>d</sub>, a comparison was not possible for these subjects, and the total statistics are based on n = 35. The t and p values refer to the difference of the mean difference from an expectation of 0 (single sample t test). Three equations produced estimates that were not significantly different to the chamber calorimetry data.</p></fn></table-wrap-foot></table-wrap></p><p id="p0055">The new equation is as follows:<disp-formula id="fd1"><label>(Equation 1)</label><mml:math id="M1" altimg="si1.gif"><mml:mrow><mml:msub><mml:mtext>rCO</mml:mtext><mml:mn>2</mml:mn></mml:msub><mml:mo linebreak="badbreak">=</mml:mo><mml:mrow><mml:mo>[</mml:mo><mml:mrow><mml:mrow><mml:mo>(</mml:mo><mml:mtext>N/</mml:mtext><mml:mn>2.078</mml:mn><mml:mo>)</mml:mo></mml:mrow><mml:mtext>∗</mml:mtext><mml:mrow><mml:mo>(</mml:mo><mml:mrow><mml:mn>1.007</mml:mn><mml:mtext>∗</mml:mtext><mml:msub><mml:mtext>k</mml:mtext><mml:mtext>o</mml:mtext></mml:msub><mml:mtext>– </mml:mtext><mml:mn>1.043</mml:mn><mml:mtext>∗</mml:mtext><mml:msub><mml:mtext>k</mml:mtext><mml:mtext>d</mml:mtext></mml:msub></mml:mrow><mml:mo>)</mml:mo></mml:mrow><mml:mtext> – </mml:mtext><mml:mrow><mml:mo>(</mml:mo><mml:mrow><mml:mn>0.0246</mml:mn><mml:mtext>∗N∗</mml:mtext><mml:mn>1.05</mml:mn><mml:mrow><mml:mo>(</mml:mo><mml:mrow><mml:mn>1.007</mml:mn><mml:mtext>∗</mml:mtext><mml:msub><mml:mtext>k</mml:mtext><mml:mtext>o</mml:mtext></mml:msub><mml:mtext>– </mml:mtext><mml:mn>1.043</mml:mn><mml:mtext>∗</mml:mtext><mml:msub><mml:mtext>k</mml:mtext><mml:mtext>d</mml:mtext></mml:msub></mml:mrow><mml:mo>)</mml:mo></mml:mrow></mml:mrow><mml:mo>)</mml:mo></mml:mrow></mml:mrow><mml:mo>]</mml:mo></mml:mrow><mml:mtext>∗</mml:mtext><mml:mn>22.26</mml:mn><mml:mtext>,</mml:mtext></mml:mrow></mml:math></disp-formula>where<disp-formula id="fd2"><label>(Equation 2)</label><mml:math id="M2" altimg="si2.gif"><mml:mrow><mml:mtext>N </mml:mtext><mml:mo linebreak="badbreak">=</mml:mo><mml:mrow><mml:mo>[</mml:mo><mml:mrow><mml:mrow><mml:mo>(</mml:mo><mml:mrow><mml:msub><mml:mtext>N</mml:mtext><mml:mtext>o</mml:mtext></mml:msub><mml:mtext>/</mml:mtext><mml:mn>1.007</mml:mn></mml:mrow><mml:mo>)</mml:mo></mml:mrow><mml:mtext> </mml:mtext><mml:mo linebreak="badbreak">+</mml:mo><mml:mtext> </mml:mtext><mml:mrow><mml:mo>(</mml:mo><mml:mrow><mml:msub><mml:mtext>N</mml:mtext><mml:mtext>d</mml:mtext></mml:msub><mml:mtext>/</mml:mtext><mml:mn>1.043</mml:mn></mml:mrow><mml:mo>)</mml:mo></mml:mrow></mml:mrow><mml:mo>]</mml:mo></mml:mrow><mml:mtext>/</mml:mtext><mml:mn>2.</mml:mn></mml:mrow></mml:math></disp-formula>N is total body water. Using the dilution spaces of both isotopes to estimate N reduces the error due to analytical variation in the derivation of either isotope space alone. However, if it is felt that the analytical variation stems mostly from evaluation of the deuterium dilution space N<sub>d</sub>, then it is also acceptable to calculate N from the oxygen dilution space alone (N = N<sub>o</sub> /1.007). The value 22.26 in <xref rid="fd1" ref-type="disp-formula">Equation 1</xref> is the gas constant for carbon dioxide. Note that this differs from the value used previously in all DLW equations for calculation of rCO<sub>2</sub> of 22.4, which is erroneously high (by 0.7%) because CO<sub>2</sub> does not show ideal gas behavior.<xref rid="bib23" ref-type="bibr"><sup>23</sup></xref></p><p id="p0060"><xref rid="fd1" ref-type="disp-formula">Equation 1</xref> can be simplified for calculation purposes to<disp-formula id="fd3"><label>(Equation 3)</label><mml:math id="M3" altimg="si3.gif"><mml:mrow><mml:msub><mml:mtext>rCO</mml:mtext><mml:mn>2</mml:mn></mml:msub><mml:mo linebreak="badbreak">=</mml:mo><mml:mn>0.4554</mml:mn><mml:mtext>∗N∗</mml:mtext><mml:mrow><mml:mo>[</mml:mo><mml:mrow><mml:mrow><mml:mo>(</mml:mo><mml:mrow><mml:mn>1.007</mml:mn><mml:mtext>∗</mml:mtext><mml:msub><mml:mtext>k</mml:mtext><mml:mtext>o</mml:mtext></mml:msub></mml:mrow><mml:mo>)</mml:mo></mml:mrow><mml:mo>-</mml:mo><mml:mrow><mml:mo>(</mml:mo><mml:mrow><mml:mn>1.043</mml:mn><mml:mtext>∗</mml:mtext><mml:msub><mml:mtext>k</mml:mtext><mml:mtext>d</mml:mtext></mml:msub></mml:mrow><mml:mo>)</mml:mo></mml:mrow></mml:mrow><mml:mo>]</mml:mo></mml:mrow><mml:mtext>∗</mml:mtext><mml:mn>22.26</mml:mn></mml:mrow></mml:math></disp-formula>or<disp-formula id="fd4"><label>(Equation 4)</label><mml:math id="M4" altimg="si4.gif"><mml:mrow><mml:msub><mml:mtext>rCO</mml:mtext><mml:mn>2</mml:mn></mml:msub><mml:mo linebreak="badbreak">=</mml:mo><mml:mrow><mml:mo>[</mml:mo><mml:mrow><mml:mtext>N∗</mml:mtext><mml:mrow><mml:mo>(</mml:mo><mml:mrow><mml:mrow><mml:mo>(</mml:mo><mml:mrow><mml:mn>0.45859</mml:mn><mml:mtext>∗</mml:mtext><mml:msub><mml:mtext>k</mml:mtext><mml:mtext>o</mml:mtext></mml:msub></mml:mrow><mml:mo>)</mml:mo></mml:mrow><mml:mo>-</mml:mo><mml:mrow><mml:mo>(</mml:mo><mml:mrow><mml:mn>0.47498</mml:mn><mml:mtext>∗</mml:mtext><mml:msub><mml:mtext>k</mml:mtext><mml:mtext>d</mml:mtext></mml:msub></mml:mrow><mml:mo>)</mml:mo></mml:mrow></mml:mrow><mml:mo>)</mml:mo></mml:mrow></mml:mrow><mml:mo>]</mml:mo></mml:mrow><mml:mtext>∗</mml:mtext><mml:mn>22.26</mml:mn><mml:mtext>,</mml:mtext></mml:mrow></mml:math></disp-formula>where k<sub>o</sub> and k<sub>d</sub> are in units of d<sup>−1</sup>, N<sub>o</sub> and N<sub>d</sub> are in mols, and rCO<sub>2</sub> is in L/d.</p><p id="p0065">We used the original RQ estimates from the publications to convert rCO<sub>2</sub> to TEE using the Weir equation.<xref rid="bib24" ref-type="bibr"><sup>24</sup></xref><disp-formula id="fd5"><label>(Equation 5)</label><mml:math id="M5" altimg="si5.gif"><mml:mrow><mml:mtext>TEE </mml:mtext><mml:mrow><mml:mo>(</mml:mo><mml:mtext>MJ/d</mml:mtext><mml:mo>)</mml:mo></mml:mrow><mml:msub><mml:mrow><mml:mo>=</mml:mo><mml:mtext> rCO</mml:mtext></mml:mrow><mml:mn>2</mml:mn></mml:msub><mml:mtext>∗</mml:mtext><mml:mrow><mml:mo>(</mml:mo><mml:mrow><mml:mn>1.106</mml:mn><mml:mo linebreak="badbreak">+</mml:mo><mml:mrow><mml:mo>(</mml:mo><mml:mn>3.94</mml:mn><mml:mtext>/RQ</mml:mtext><mml:mo>)</mml:mo></mml:mrow></mml:mrow><mml:mo>)</mml:mo></mml:mrow><mml:mtext> ∗ </mml:mtext><mml:mrow><mml:mo>(</mml:mo><mml:msup><mml:mrow><mml:mn>4.184</mml:mn><mml:mtext>/</mml:mtext><mml:mn>10</mml:mn></mml:mrow><mml:mn>3</mml:mn></mml:msup><mml:mo>)</mml:mo></mml:mrow><mml:mo>.</mml:mo></mml:mrow></mml:math></disp-formula><xref rid="fig1" ref-type="fig">Figure 1</xref>A shows the estimates of rCO<sub>2</sub> from the original publications, plotted against estimates using <xref rid="fd1" ref-type="disp-formula">Equation 1</xref>. Although there is a strong association between the estimates (r<sup>2</sup> = 0.987), they do not yield identical rCO<sub>2</sub> values. Because the equation based on Sagayama et al.<xref rid="bib20" ref-type="bibr"><sup>20</sup></xref> was derived here, none of the studies in the database used this equation. Of the 5,756 individual data, the rCO<sub>2</sub> of 1,024 (17.7%) was made using the equation of Coward and Prentice,<xref rid="bib22" ref-type="bibr"><sup>22</sup></xref> 883 (15.3%) were made using the Schoeller et al.<xref rid="bib15" ref-type="bibr"><sup>15</sup></xref> Equation A6 as modified in 1988,<xref rid="bib18" ref-type="bibr"><sup>18</sup></xref> 3,770 (65.3%) were made using the Racette et al.<xref rid="bib19" ref-type="bibr"><sup>19</sup></xref> equation, and 77 (1.3%) did not state the equation they used. The Racette et al.<xref rid="bib19" ref-type="bibr"><sup>19</sup></xref> equation produces estimates very similar to those derived from <xref rid="fd1" ref-type="disp-formula">Equation 1</xref> (<xref rid="tbl1" ref-type="table">Table 1</xref>), and the discrepancy in the sample of 3,770 using this equation averaged 1.1% (SD 1.2). On average, the discrepancy when using the Schoeller et al.<xref rid="bib15" ref-type="bibr"><sup>15</sup></xref> A6 equation was 1.8% (SD 1.6), and for the studies using the Coward and Prentice<xref rid="bib22" ref-type="bibr"><sup>22</sup></xref> equation, it was 4.4% (SD 4.6).<fig id="fig1"><label>Figure 1</label><caption><p>Comparison of published CO<sub>2</sub> production by doubly labeled water to that by standard method</p><p>(A) Relationship between CO<sub>2</sub> production (L/d) for 5,756 individuals extracted from the original studies and the recalculated estimates using <xref rid="fd1" ref-type="disp-formula">Equation 1</xref>.</p><p>(B–D) Bland-Altman plots<xref rid="bib25" ref-type="bibr"><sup>25</sup></xref> comparing the published rCO<sub>2</sub> for studies using (B) the Coward and Prentice<xref rid="bib22" ref-type="bibr"><sup>22</sup></xref> equation, (C) the Schoeller et al.<xref rid="bib15" ref-type="bibr"><sup>15</sup></xref> A6 equation, and (D) the Racette et al.<xref rid="bib19" ref-type="bibr"><sup>19</sup></xref> compared with the standard <xref rid="fd1" ref-type="disp-formula">Equation 1</xref> derived from Sagayama et al.<xref rid="bib20" ref-type="bibr"><sup>20</sup></xref> In all plots, dotted line is average difference, and solid blue lines are plus and minus 2 SDs. The red lines define the boundary for plus and minus 10% difference between methods. Data refer to 5,756 adult individuals uploaded into the IAEA DLW database (v3.1).</p></caption><graphic xlink:href="gr1"></graphic></fig></p><p id="p0070">We compared the rCO<sub>2</sub> values calculated using the three main equations compared to <xref rid="fd1" ref-type="disp-formula">Equation 1</xref> using Bland-Altman plots (<xref rid="fig1" ref-type="fig">Figures 1</xref>B–1D).<xref rid="bib25" ref-type="bibr"><sup>25</sup></xref> For all three equations, there was no systematic bias. However, the Coward and Prentice<xref rid="bib22" ref-type="bibr"><sup>22</sup></xref> equation generated far more variable estimates than the other two equations. This is expected because that calculation utilizes individual values for N<sub>o</sub> and N<sub>d</sub> instead of using an average N<sub>d</sub>/N<sub>o</sub> ratio, which is used in the other two equations and <xref rid="fd1" ref-type="disp-formula">Equation 1</xref>. Indeed, of the 1,024 estimates using the Coward equation, 103 (10.0%) differed by more than 10% from the standard, compared to 1/883 (0.1%) for the Schoeller et al.<xref rid="bib15" ref-type="bibr"><sup>15</sup></xref> equation and 12/3,770 (0.3%) for the Racette<xref rid="bib19" ref-type="bibr"><sup>19</sup></xref> equation.</p><p id="p0075">A second source of variation can be introduced by using alternative equations to convert rCO<sub>2</sub> to TEE. This variation occurs even when the RQ is known. To evaluate the variation introduced from this source, we took the original rCO<sub>2</sub> and converted this to TEE using the Weir equation. We then compared the recalculated TEE with the published values. The relationship between the recalculated and original TEE values (<xref rid="fig2" ref-type="fig">Figure 2</xref>A) was very good (r<sup>2</sup> = 0.99), and the average discrepancy between estimates was only 0.08 MJ/d (SD = 0.19) or 0.8% (SD = 0.19). The absolute discrepancy excluding the sign of the difference was 0.11 MJ (1.1%; SD = 0.17). There was no significant trend in the discrepancy with the magnitude of the TEE (<xref rid="fig2" ref-type="fig">Figure 2</xref>B). When RQ is not known, the routine procedure is to approximate the RQ using the FQ. The errors involved in this approximation are beyond the scope of this paper and are not addressed here.<fig id="fig2"><label>Figure 2</label><caption><p>Comparison of published energy expenditure by DLW to that calculated by standard method</p><p>(A) Relationship between the TEE (MJ/d) for 4,571 individual adults extracted from the original studies and the recalculated TEE using the Weir equation.</p><p>(B) Bland-Altman plot<xref rid="bib25" ref-type="bibr"><sup>25</sup></xref> comparing the published TEE with those generated using the recommended equation. Dotted line is average difference. Data refer to data for 4,571 adult individuals uploaded into the IAEA DLW database (v3.1). The sample size is lower than in <xref rid="fig1" ref-type="fig">Figure 1</xref>, because for some individuals, estimates of RQ or FQ were not available.</p></caption><graphic xlink:href="gr2"></graphic></fig></p><p id="p0080">These data show that selection of the calculation method can introduce substantial variation into the individual and to a lesser extent average estimates of rCO<sub>2</sub>, as well as to variation in conversion of rCO<sub>2</sub> to TEE. For comparisons made within studies, this discrepancy is unimportant. However, it may introduce problems when comparisons are attempted between studies or when the DLW method is used to validate other techniques, particularly when small sample sizes are employed. With some equations in common use, more than 10% of estimates are greater than 10% divergent from the equation that performs best in validation studies. Such differences between calculation methods across studies might be erroneously attributed to biological factors. This potential problem is compounded by the fact that some studies do not indicate the exact calculation methods they employed to derive rCO<sub>2</sub> and TEE estimates. To overcome these issues, we recommend adoption of <xref rid="fd1" ref-type="disp-formula">Equation 1</xref> in future studies of children, adolescents, and adults to derive rCO<sub>2</sub> and use of <xref rid="fd5" ref-type="disp-formula">Equation 5</xref> to convert this to TEE.</p></sec><sec id="sec2.2"><title>Small infants and babies</title><p id="p0085">The recommendation above refers to subjects aged ≥2 years. We have shown that the choice of equation has a significant impact on the resultant calculation of rCO<sub>2</sub> and TEE and that the major factor driving this variation is the relative dilutions spaces of N<sub>o</sub> and N<sub>d</sub> (the dilution space ratio DSR = N<sub>d</sub>/N<sub>o</sub>; <xref rid="fig3" ref-type="fig">Figure 3</xref>). There is evidence that, at younger ages, the DSR is below the observed average of 1.036 in individuals aged >2 years.<xref rid="bib20" ref-type="bibr"><sup>20</sup></xref><sup>,</sup><xref rid="bib26" ref-type="bibr"><sup>26</sup></xref> In a review of 36 studies of 1,131 young children, the weighted dilution space ratio averaged 1.031,<xref rid="bib20" ref-type="bibr"><sup>20</sup></xref> which means that application of <xref rid="fd1" ref-type="disp-formula">Equation 1</xref> to younger individuals may yield underestimates of rCO<sub>2</sub> and TEE.<fig id="fig3"><label>Figure 3</label><caption><p>Dilution space ratio as a function of body mass and performance of new equation against indirect calorimetry</p><p>(A) Dilution space ratios (the hydrogen dilution space N<sub>d</sub> divided by the oxygen dilution space N<sub>o</sub>) of 332 babies weighing <10 kg from the IAEA DLW database v 3.1 (open circles) combined with data from validation studies in preterm and full-term babies (gray circles). For the sample from the database, there was a linear relationship (blue dotted line that marginally failed to reach significance p = 0.08). We fitted an asymptotic exponential to the combined dataset (red line; r<sup>2</sup> = 6.4%; p < 0.03).</p><p>(B) The results of validation studies of the DLW method in babies comparing the DLW estimates of CO<sub>2</sub> production (rCO<sub>2</sub>) derived from a combination of <xref rid="fd9" ref-type="disp-formula">Equations 9</xref> and <xref rid="fd10" ref-type="disp-formula">10</xref> presented here and rCO<sub>2</sub> measured by indirect calorimetry. There was a strong linear relationship fitted by least-squares regression—dotted blue line, with r<sup>2</sup> = 0.90.</p></caption><graphic xlink:href="gr3"></graphic></fig></p><p id="p0090">There is a problem, however, in choosing the best equation to use in young children, and that is the limitation on performing validation experiments in this age group against gas exchange measurements by indirect calorimetry (chamber respirometry). Validation studies of DLW against indirect calorimetry will probably never be performed in young children because it would require the child to be isolated within a respirometry chamber for a protracted period lasting up to a week.</p><p id="p0095">Nevertheless, a number of validation studies have been performed in preterm babies and small neonates (<2 kg), comparing continuous gas exchange with DLW.<xref rid="bib27" ref-type="bibr">27</xref>, <xref rid="bib28" ref-type="bibr">28</xref>, <xref rid="bib29" ref-type="bibr">29</xref> The problem, however, is that such very small children weighing less than 2 kg have an even lower DSR,<xref rid="bib30" ref-type="bibr"><sup>30</sup></xref> averaging around 1.019, significantly lower than in infants weighing >2 kg.<xref rid="bib26" ref-type="bibr"><sup>26</sup></xref><sup>,</sup><xref rid="bib31" ref-type="bibr"><sup>31</sup></xref> Hence, an equation based on this DSR might work well for small babies weighing less than 2 kg, but it might be unsuitable for infants weighing 2–10 kg. Fortunately, there is a single validation study of babies weighing 2–4.2 kg,<xref rid="bib32" ref-type="bibr"><sup>32</sup></xref> which can assist in selection of the best equation in this size range.</p><p id="p0100">We compiled data from the four available validation studies in babies and used the published data in these studies on isotope elimination rates of 18oxygen (k<sub>o</sub>) and deuterium (k<sub>d</sub>) and the respective dilution spaces (N<sub>o</sub> and N<sub>d</sub>) to recalculate the rCO<sub>2</sub> using five different alternative equations. We then derived two new equations in which we replaced the DSR in <xref rid="fd1" ref-type="disp-formula">Equation 1</xref> with either the value 1.019 or the value 1.031. These are, respectively, when the DSR = 1.019,<disp-formula id="fd6"><label>(Equation 6)</label><mml:math id="M6" altimg="si6.gif"><mml:mrow><mml:msub><mml:mtext>rCO</mml:mtext><mml:mn>2</mml:mn></mml:msub><mml:mo linebreak="badbreak">=</mml:mo><mml:mrow><mml:mo>[</mml:mo><mml:mrow><mml:mrow><mml:mo>(</mml:mo><mml:mtext>N/</mml:mtext><mml:mn>2.078</mml:mn><mml:mo>)</mml:mo></mml:mrow><mml:mtext>∗</mml:mtext><mml:mrow><mml:mo>(</mml:mo><mml:mrow><mml:mn>1.007</mml:mn><mml:mtext>∗</mml:mtext><mml:msub><mml:mtext>k</mml:mtext><mml:mtext>o</mml:mtext></mml:msub><mml:mtext>– </mml:mtext><mml:mn>1.026</mml:mn><mml:mtext>∗</mml:mtext><mml:msub><mml:mtext>k</mml:mtext><mml:mtext>d</mml:mtext></mml:msub></mml:mrow><mml:mo>)</mml:mo></mml:mrow><mml:mtext> – </mml:mtext><mml:mrow><mml:mo>(</mml:mo><mml:mrow><mml:mn>0.0246</mml:mn><mml:mtext>∗N∗</mml:mtext><mml:mn>1.05</mml:mn><mml:mrow><mml:mo>(</mml:mo><mml:mrow><mml:mn>1.007</mml:mn><mml:mtext>∗</mml:mtext><mml:msub><mml:mtext>k</mml:mtext><mml:mtext>o</mml:mtext></mml:msub><mml:mtext>– </mml:mtext><mml:mn>1.026</mml:mn><mml:mtext>∗</mml:mtext><mml:msub><mml:mtext>k</mml:mtext><mml:mtext>d</mml:mtext></mml:msub></mml:mrow><mml:mo>)</mml:mo></mml:mrow></mml:mrow><mml:mo>)</mml:mo></mml:mrow></mml:mrow><mml:mo>]</mml:mo></mml:mrow><mml:mtext>∗</mml:mtext><mml:mn>22.26</mml:mn><mml:mtext>,</mml:mtext></mml:mrow></mml:math></disp-formula>and when the DSR = 1.031,<disp-formula id="fd7"><label>(Equation 7)</label><mml:math id="M7" altimg="si7.gif"><mml:mrow><mml:msub><mml:mtext>rCO</mml:mtext><mml:mn>2</mml:mn></mml:msub><mml:mo linebreak="badbreak">=</mml:mo><mml:mrow><mml:mo>[</mml:mo><mml:mrow><mml:mrow><mml:mo>(</mml:mo><mml:mtext>N/</mml:mtext><mml:mn>2.078</mml:mn><mml:mo>)</mml:mo></mml:mrow><mml:mtext>∗</mml:mtext><mml:mrow><mml:mo>(</mml:mo><mml:mrow><mml:mn>1.007</mml:mn><mml:mtext>∗</mml:mtext><mml:msub><mml:mtext>k</mml:mtext><mml:mtext>o</mml:mtext></mml:msub><mml:mtext>– </mml:mtext><mml:mn>1.038</mml:mn><mml:mtext>∗</mml:mtext><mml:msub><mml:mtext>k</mml:mtext><mml:mtext>d</mml:mtext></mml:msub></mml:mrow><mml:mo>)</mml:mo></mml:mrow><mml:mtext> – </mml:mtext><mml:mrow><mml:mo>(</mml:mo><mml:mrow><mml:mn>0.0246</mml:mn><mml:mtext>∗N∗</mml:mtext><mml:mn>1.05</mml:mn><mml:mrow><mml:mo>(</mml:mo><mml:mrow><mml:mn>1.007</mml:mn><mml:mtext>∗</mml:mtext><mml:msub><mml:mtext>k</mml:mtext><mml:mtext>o</mml:mtext></mml:msub><mml:mtext>– </mml:mtext><mml:mn>1.038</mml:mn><mml:mtext>∗</mml:mtext><mml:msub><mml:mtext>k</mml:mtext><mml:mtext>d</mml:mtext></mml:msub></mml:mrow><mml:mo>)</mml:mo></mml:mrow></mml:mrow><mml:mo>)</mml:mo></mml:mrow></mml:mrow><mml:mo>]</mml:mo></mml:mrow><mml:mtext>∗</mml:mtext><mml:mn>22.26.</mml:mn></mml:mrow></mml:math></disp-formula>In all the above cases, we used<disp-formula id="fd8"><label>(Equation 8)</label><mml:math id="M8" altimg="si8.gif"><mml:mrow><mml:mtext>N</mml:mtext><mml:msub><mml:mrow><mml:mo>=</mml:mo><mml:mtext> N</mml:mtext></mml:mrow><mml:mtext>o</mml:mtext></mml:msub><mml:mtext>/</mml:mtext><mml:mn>1.007.</mml:mn></mml:mrow></mml:math></disp-formula>Although there have been relatively few validation studies of humans weighing less than 4 kg, there have been a large number of validation studies in small mammals and birds in this weight range (reviewed in Speakman<xref rid="bib3" ref-type="bibr"><sup>3</sup></xref>). Although such animals have dilution space ratios that do not differ from adult humans (around 1.036), the best equation in validation studies of such animals turns out to be based on a DSR of 1.0. This is because these animals have a significant efflux of deuterium in addition to water turnover that offsets the impact of the slightly different DSRs.<xref rid="bib33" ref-type="bibr"><sup>33</sup></xref> Because this might also pertain in babies, we added into the evaluation the most widespread equation in use for small mammals and birds, which is Equation 7.17 from Speakman.<xref rid="bib3" ref-type="bibr"><sup>3</sup></xref> Finally, we also added into the evaluation the equation of Coward and Prentice,<xref rid="bib22" ref-type="bibr"><sup>22</sup></xref> which uses individual dilution spaces rather than a population average in the calculation.</p><p id="p0105"><xref rid="tbl1" ref-type="table">Table 1</xref> shows the results of the different equations when compared to indirect calorimetry for preterm infants (≤2 kg) and infants weighing >2 kg. The data show that, in the size range 0–2 kg, the best equation was based on the dilution space ratio 1.019 (<xref rid="fd6" ref-type="disp-formula">Equation 6</xref> above). The average difference between the rCO<sub>2</sub> by indirect calorimetry and DLW using this equation was 0.5%. This was much better than the equation derived for children and adults (<xref rid="fd1" ref-type="disp-formula">Equation 1</xref>), which gave an estimate 13.5% too low, and <xref rid="fd7" ref-type="disp-formula">Equation 7</xref> above, which gave an estimate 8.4% too low. The equation that performs best in validation studies of small mammals gave an estimate 10.1% too high, clearly indicating the physiological basis for this equation, although appropriate for birds and small non-human mammals, does not apply to neonatal humans and young infants.</p><p id="p0110">In the size range 2–4 kg, the best equation was that based on the DSR of 1.031 (<xref rid="fd7" ref-type="disp-formula">Equation 7</xref>). <xref rid="fd1" ref-type="disp-formula">Equation 1</xref> gave an estimate 8.5% too low. <xref rid="fd6" ref-type="disp-formula">Equation 6</xref> gave an estimate 6.5% too high, although the small animal equation gave an estimate 16.8% too high. These validation data therefore suggest that adoption of three different equations over different size ranges corresponding to different DSRs might be a possible solution to the issue of how to measure rCO<sub>2</sub> by DLW. For individuals weighing <2 kg, the suggested equation would be <xref rid="fd6" ref-type="disp-formula">Equation 6</xref>; for individuals weighing 2–10 kg, it would be <xref rid="fd7" ref-type="disp-formula">Equation 7</xref>, and for individuals weighing >10 kg, it would be <xref rid="fd1" ref-type="disp-formula">Equation 1</xref>.</p><p id="p0115">This approach, however, is not very satisfactory, because it leads to confusion at the boundaries of the weight ranges. For example, for a 2-kg child, rCO<sub>2</sub> calculated using <xref rid="fd6" ref-type="disp-formula">Equation 6</xref> differs from that calculated by <xref rid="fd7" ref-type="disp-formula">Equation 7</xref> by about 10%. To further explore the choice of DSR in the size range 0–10 kg, we extracted data from the IAEA DLW database<xref rid="bib8" ref-type="bibr"><sup>8</sup></xref> for individuals in this size range. In fact, none of the individuals in the database weighed less than 2 kg, but there were 336 records of children weighing between 2.4 and 10 kg. The DSR for these individuals is plotted against the body weight in <xref rid="fig1" ref-type="fig">Figure 1</xref>A. The average DSR in this interval was 1.032 (SD = 0.0122), consistent with the previous suggestion of 1.031 (Sagayama et al.<xref rid="bib20" ref-type="bibr"><sup>20</sup></xref>). This DSR was significantly lower than the ratio established for heavier individuals of 1.036 (t = −5.72; p < 0.0001) and significantly higher than the ratio of 1.019 for preterm babies and neonates<xref rid="bib30" ref-type="bibr"><sup>30</sup></xref> weighing less than 2 kg (t = 22.26; p < 0.001). There was a trend for a positive association between weight and DSR through the size range (regression r<sup>2</sup> = 0.9%; p = 0.08). When we combined these data with those from the validation studies,<xref rid="bib27" ref-type="bibr">27</xref>, <xref rid="bib28" ref-type="bibr">28</xref>, <xref rid="bib29" ref-type="bibr">29</xref><sup>,</sup><xref rid="bib32" ref-type="bibr"><sup>32</sup></xref> there was a significant non-linear relationship between body mass (BM) (kg) and DSR. We fitted an asymptotic exponential model to these data constraining the asymptote to be 1.036 using a non-linear fitting function in the program MINITAB to estimate the unknown parameters. The resultant equation was<disp-formula id="fd9"><label>(Equation 9)</label><mml:math id="M9" altimg="si9.gif"><mml:mrow><mml:mtext>DSR </mml:mtext><mml:mo linebreak="badbreak">=</mml:mo><mml:mtext> 1.036 </mml:mtext><mml:mo>-</mml:mo><mml:mn>0.05</mml:mn><mml:mtext>∗exp</mml:mtext><mml:mrow><mml:mo>(</mml:mo><mml:mo>-</mml:mo><mml:mn>0.5249</mml:mn><mml:mtext>∗BM</mml:mtext><mml:mo>)</mml:mo></mml:mrow><mml:mo>,</mml:mo></mml:mrow></mml:math></disp-formula>where BM is in kg.</p><p id="p0120">A different approach then is to create an equation that combines this weight dependency with the standard equation, yielding<disp-formula id="fd10"><label>(Equation 10)</label><mml:math id="M10" altimg="si10.gif"><mml:mrow><mml:msub><mml:mtext>rCO</mml:mtext><mml:mn>2</mml:mn></mml:msub><mml:mo linebreak="badbreak">=</mml:mo><mml:mrow><mml:mo>[</mml:mo><mml:mrow><mml:mrow><mml:mo>(</mml:mo><mml:mtext>N/</mml:mtext><mml:mn>2.078</mml:mn><mml:mo>)</mml:mo></mml:mrow><mml:mtext>∗</mml:mtext><mml:mrow><mml:mo>(</mml:mo><mml:mrow><mml:mn>1.007</mml:mn><mml:mtext>∗</mml:mtext><mml:msub><mml:mtext>k</mml:mtext><mml:mtext>o</mml:mtext></mml:msub><mml:mtext>– </mml:mtext><mml:mrow><mml:mo>(</mml:mo><mml:mrow><mml:mtext>DSR∗</mml:mtext><mml:mn>1.007</mml:mn><mml:mtext>∗</mml:mtext><mml:msub><mml:mtext>k</mml:mtext><mml:mtext>d</mml:mtext></mml:msub></mml:mrow><mml:mo>)</mml:mo></mml:mrow></mml:mrow><mml:mo>)</mml:mo></mml:mrow></mml:mrow><mml:mo>]</mml:mo></mml:mrow><mml:mtext> – </mml:mtext><mml:mrow><mml:mo>[</mml:mo><mml:mrow><mml:mn>0.0246</mml:mn><mml:mtext>∗N∗</mml:mtext><mml:mn>1.05</mml:mn><mml:mrow><mml:mo>(</mml:mo><mml:mrow><mml:mn>1.007</mml:mn><mml:mtext>∗</mml:mtext><mml:msub><mml:mtext>k</mml:mtext><mml:mtext>o</mml:mtext></mml:msub><mml:mtext>– </mml:mtext><mml:mrow><mml:mo>(</mml:mo><mml:mrow><mml:mtext>DSR∗</mml:mtext><mml:mn>1.007</mml:mn><mml:mtext>∗</mml:mtext><mml:msub><mml:mtext>k</mml:mtext><mml:mtext>d</mml:mtext></mml:msub></mml:mrow><mml:mo>)</mml:mo></mml:mrow></mml:mrow><mml:mo>)</mml:mo></mml:mrow></mml:mrow><mml:mo>]</mml:mo></mml:mrow><mml:mtext>∗</mml:mtext><mml:mn>22.26</mml:mn><mml:mtext>,</mml:mtext></mml:mrow></mml:math></disp-formula>where N = N<sub>o</sub> and DSR is defined in <xref rid="fd9" ref-type="disp-formula">Equation 9</xref> by the BM in kg.</p><p id="p0125">For calculation purposes, this simplifies to<disp-formula id="fd11"><label>(Equation 11)</label><mml:math id="M11" altimg="si11.gif"><mml:mrow><mml:msub><mml:mtext>rCO</mml:mtext><mml:mn>2</mml:mn></mml:msub><mml:mo linebreak="badbreak">=</mml:mo><mml:mrow><mml:mo>[</mml:mo><mml:mrow><mml:mn>0.45859</mml:mn><mml:mtext>∗N∗</mml:mtext><mml:mrow><mml:mo>(</mml:mo><mml:mrow><mml:msub><mml:mtext>k</mml:mtext><mml:mtext>o</mml:mtext></mml:msub><mml:mtext>– </mml:mtext><mml:mrow><mml:mo>(</mml:mo><mml:mrow><mml:mtext>DSR∗</mml:mtext><mml:msub><mml:mtext>k</mml:mtext><mml:mtext>d</mml:mtext></mml:msub></mml:mrow><mml:mo>)</mml:mo></mml:mrow></mml:mrow><mml:mo>)</mml:mo></mml:mrow></mml:mrow><mml:mo>]</mml:mo></mml:mrow><mml:mtext>∗</mml:mtext><mml:mn>22.26.</mml:mn></mml:mrow></mml:math></disp-formula>The results of using this equation are shown in <xref rid="tbl2" ref-type="table">Table 2</xref> (<xref rid="fd10" ref-type="disp-formula">Equation 10</xref>), and a plot of the predicted rCO<sub>2</sub> from <xref rid="fd10" ref-type="disp-formula">Equation 10</xref> and the observed rCO<sub>2</sub> across all the validation studies across the entire weight range in <xref rid="tbl2" ref-type="table">Table 2</xref> is shown in <xref rid="fig2" ref-type="fig">Figure 2</xref>B. This shows a linear relationship with an r<sup>2</sup> of 90.1% and a least-squares fit gradient of 0.954 (reduced major axis = 1.005). The average % difference across all 34 individuals in the validation studies (in <xref rid="tbl2" ref-type="table">Table 2</xref>) using this equation was 0.64% (SD = 11.9). This combined equation based on the weight dependency of the DSR in the range 0–10 kg therefore performs better than the individual equations for the ranges 0–2 kg (<xref rid="fd6" ref-type="disp-formula">Equation 6</xref>) and 2–10 kg (<xref rid="fd7" ref-type="disp-formula">Equation 7</xref>; <xref rid="tbl2" ref-type="table">Table 2</xref>).<table-wrap position="float" id="tbl2"><label>Table 2</label><caption><p>Validation results for carbon dioxide production (rCO<sub>2</sub>) for 34 preterm and neonatal babies measured using the doubly labeled water method simultaneous to chamber calorimetry</p></caption><table frame="hsides" rules="groups"><thead><tr><th>Study</th><th>ID</th><th>BM</th><th>rCO<sub>2</sub> IC</th><th colspan="2"><xref rid="fd1" ref-type="disp-formula">Equation 1</xref></th><th><xref rid="fd6" ref-type="disp-formula">Equation 6</xref></th><th></th><th><xref rid="fd7" ref-type="disp-formula">Equation 7</xref></th><th></th><th colspan="2">Coward 1985</th><th colspan="2">Speakman 7.17</th><th colspan="2"><xref rid="fd10" ref-type="disp-formula">Equation 10</xref></th></tr></thead><tbody><tr><td></td><td></td><td>g</td><td>L/d</td><td>L/d</td><td>%diff</td><td>L/d</td><td>%diff</td><td>L/d</td><td>%diff</td><td>L/d</td><td>%diff</td><td>L/d</td><td>%diff</td><td>L/d</td><td>%diff</td></tr><tr><td>D</td><td>3</td><td>1,090.00</td><td>12.50</td><td>9.09</td><td>−27.27</td><td>11.4</td><td>−8.5</td><td>9.94</td><td>−20.49</td><td></td><td></td><td>12.80</td><td>2.40</td><td>12.85</td><td>2.81</td></tr><tr><td>B</td><td>3</td><td>1,115.00</td><td>11.37</td><td>10.00</td><td>−12.08</td><td>11.4</td><td>0.3</td><td>10.51</td><td>−7.63</td><td>8.53</td><td>−25.04</td><td>12.44</td><td>9.36</td><td>12.22</td><td>7.44</td></tr><tr><td>B</td><td>7</td><td>1,195.00</td><td>14.58</td><td>13.60</td><td>−6.74</td><td>15.3</td><td>4.8</td><td>14.20</td><td>−2.57</td><td>11.91</td><td>−18.32</td><td>16.60</td><td>13.85</td><td>16.16</td><td>10.82</td></tr><tr><td>D</td><td>2</td><td>1,378.00</td><td>13.70</td><td>13.64</td><td>−0.45</td><td>15.9</td><td>15.8</td><td>14.44</td><td>5.40</td><td></td><td></td><td>17.39</td><td>26.93</td><td>16.72</td><td>22.07</td></tr><tr><td>A</td><td>10</td><td>1,414.85</td><td>17.72</td><td>13.48</td><td>−23.91</td><td>15.8</td><td>−10.8</td><td>14.32</td><td>−19.18</td><td>14.59</td><td>−17.65</td><td>17.37</td><td>−1.98</td><td>16.65</td><td>−6.02</td></tr><tr><td>D</td><td>4</td><td>1,496.00</td><td>17.00</td><td>14.99</td><td>−11.85</td><td>17.8</td><td>4.7</td><td>16.00</td><td>−5.87</td><td></td><td></td><td>19.63</td><td>15.47</td><td>18.68</td><td>9.87</td></tr><tr><td>A</td><td>1</td><td>1,520.65</td><td>18.29</td><td>13.13</td><td>−28.24</td><td>15.4</td><td>−15.7</td><td>13.95</td><td>−23.71</td><td>12.90</td><td>−29.50</td><td>16.96</td><td>−7.29</td><td>16.10</td><td>−11.97</td></tr><tr><td>B</td><td>1</td><td>1,545.00</td><td>14.83</td><td>13.94</td><td>−6.03</td><td>16.2</td><td>9.2</td><td>14.75</td><td>−0.55</td><td>9.86</td><td>−33.50</td><td>17.74</td><td>19.63</td><td>16.82</td><td>13.40</td></tr><tr><td>A</td><td>5</td><td>1,596.45</td><td>19.74</td><td>19.16</td><td>−2.95</td><td>21.6</td><td>9.6</td><td>20.05</td><td>1.58</td><td>17.70</td><td>−10.36</td><td>23.53</td><td>19.22</td><td>22.25</td><td>12.73</td></tr><tr><td>B</td><td>4</td><td>1,600.00</td><td>15.52</td><td>14.61</td><td>−5.85</td><td>17.2</td><td>11.0</td><td>15.55</td><td>0.21</td><td>11.80</td><td>−24.00</td><td>18.94</td><td>22.07</td><td>17.86</td><td>15.08</td></tr><tr><td>B</td><td>6</td><td>1,640.00</td><td>18.70</td><td>17.48</td><td>−6.53</td><td>19.8</td><td>5.9</td><td>18.31</td><td>−2.04</td><td>15.12</td><td>−19.15</td><td>21.56</td><td>15.31</td><td>20.32</td><td>8.69</td></tr><tr><td>B</td><td>2</td><td>1,660.00</td><td>17.76</td><td>16.77</td><td>−5.58</td><td>19.5</td><td>9.7</td><td>17.75</td><td>−0.08</td><td>13.71</td><td>−22.79</td><td>21.35</td><td>20.21</td><td>20.05</td><td>12.88</td></tr><tr><td>A</td><td>8</td><td>1,692.15</td><td>20.01</td><td>18.01</td><td>−10.00</td><td>20.9</td><td>4.2</td><td>19.04</td><td>−4.87</td><td>18.38</td><td>−8.15</td><td>22.85</td><td>14.15</td><td>21.41</td><td>6.96</td></tr><tr><td>A</td><td>7</td><td>1,702.70</td><td>22.88</td><td>26.77</td><td>16.98</td><td>29.3</td><td>28.0</td><td>27.68</td><td>20.96</td><td>26.82</td><td>17.18</td><td>31.58</td><td>37.99</td><td>29.76</td><td>30.06</td></tr><tr><td>A</td><td>9</td><td>1,709.20</td><td>21.17</td><td>13.92</td><td>−34.24</td><td>16.5</td><td>−21.9</td><td>14.87</td><td>−29.79</td><td>15.35</td><td>−27.49</td><td>18.23</td><td>−13.89</td><td>17.01</td><td>−19.65</td></tr><tr><td>A</td><td>11</td><td>1,783.30</td><td>22.61</td><td>18.81</td><td>−16.79</td><td>21.6</td><td>−4.4</td><td>19.83</td><td>−12.31</td><td>19.35</td><td>−14.44</td><td>23.63</td><td>4.50</td><td>22.01</td><td>−2.64</td></tr><tr><td>A</td><td>12</td><td>1,824.10</td><td>21.17</td><td>18.87</td><td>−10.85</td><td>21.4</td><td>1.2</td><td>19.79</td><td>−6.50</td><td>19.78</td><td>−6.55</td><td>23.33</td><td>10.25</td><td>21.72</td><td>2.64</td></tr><tr><td>B</td><td>8</td><td>1,830.00</td><td>21.23</td><td>19.09</td><td>−10.09</td><td>21.8</td><td>2.6</td><td>20.06</td><td>−5.52</td><td>18.06</td><td>−14.93</td><td>23.75</td><td>11.89</td><td>22.09</td><td>4.04</td></tr><tr><td>B</td><td>5</td><td>1,860.00</td><td>18.97</td><td>15.54</td><td>−18.08</td><td>18.4</td><td>−3.2</td><td>16.56</td><td>−12.70</td><td>14.00</td><td>−26.19</td><td>20.22</td><td>6.60</td><td>18.65</td><td>−1.71</td></tr><tr><td>A</td><td>6</td><td>1,862.40</td><td>18.44</td><td>14.19</td><td>−23.06</td><td>16.8</td><td>−9.0</td><td>15.12</td><td>−17.99</td><td>14.76</td><td>−19.98</td><td>18.48</td><td>0.21</td><td>17.03</td><td>−7.63</td></tr><tr><td>A</td><td>4</td><td>1,880.70</td><td>25.36</td><td>22.30</td><td>−12.06</td><td>25.1</td><td>−0.9</td><td>23.32</td><td>−8.03</td><td>22.64</td><td>−10.74</td><td>27.32</td><td>7.74</td><td>25.39</td><td>0.10</td></tr><tr><td>A</td><td>3</td><td>1,894.95</td><td>25.47</td><td>12.37</td><td>−51.44</td><td>16.4</td><td>−35.7</td><td>13.81</td><td>−45.77</td><td>15.32</td><td>−39.84</td><td>18.53</td><td>−27.24</td><td>16.69</td><td>−34.47</td></tr><tr><td>C</td><td>6</td><td>1,920.00</td><td>21.95</td><td>21.99</td><td>0.16</td><td>25.7</td><td>17.3</td><td>23.34</td><td>6.33</td><td></td><td></td><td>28.27</td><td>28.77</td><td>25.99</td><td>18.40</td></tr><tr><td>A</td><td>2</td><td>1,996.80</td><td>23.04</td><td>19.40</td><td>−15.79</td><td>22.5</td><td>−2.5</td><td>20.50</td><td>−10.98</td><td>19.33</td><td>−16.09</td><td>24.60</td><td>6.81</td><td>22.56</td><td>−2.08</td></tr><tr><td>Mean</td><td></td><td>1,633.64</td><td>18.92</td><td>16.30</td><td>−13.45</td><td>18.9</td><td>0.5</td><td>17.24</td><td>−8.42</td><td>15.99</td><td>−18.38</td><td>20.71</td><td>10.12</td><td></td><td></td></tr><tr><td>SD</td><td></td><td>252.89</td><td></td><td>4.07</td><td>13.54</td><td>4.30</td><td>13.40</td><td>4.15</td><td>13.45</td><td>4.37</td><td>11.97</td><td>4.60</td><td>14.07</td><td></td><td></td></tr><tr><td>C</td><td>1</td><td>2,570.00</td><td>27.55</td><td>25.42</td><td>−7.75</td><td>30.7</td><td>11.4</td><td>27.32</td><td>−0.85</td><td></td><td></td><td>33.97</td><td>23.30</td><td>29.56</td><td>7.28</td></tr><tr><td>D</td><td>1</td><td>2,575.00</td><td>27.90</td><td>21.67</td><td>−22.33</td><td>25.7</td><td>−7.9</td><td>23.12</td><td>−17.14</td><td></td><td></td><td>28.31</td><td>1.45</td><td>24.82</td><td>−11.04</td></tr><tr><td>C</td><td>4</td><td>2,590.00</td><td>25.98</td><td>22.39</td><td>−13.83</td><td>25.7</td><td>−1.1</td><td>23.58</td><td>−9.24</td><td></td><td></td><td>28.08</td><td>8.05</td><td>24.97</td><td>−3.92</td></tr><tr><td>C</td><td>5</td><td>2,790.00</td><td>28.00</td><td>27.36</td><td>−2.28</td><td>31.9</td><td>13.8</td><td>28.98</td><td>3.50</td><td></td><td></td><td>34.93</td><td>24.75</td><td>30.55</td><td>9.11</td></tr><tr><td>C</td><td>8</td><td>2,980.00</td><td>32.70</td><td>27.02</td><td>−17.37</td><td>32.0</td><td>−2.3</td><td>28.80</td><td>−11.94</td><td></td><td></td><td>35.19</td><td>7.59</td><td>30.23</td><td>−7.55</td></tr><tr><td>C</td><td>9</td><td>3,390.00</td><td>33.82</td><td>33.14</td><td>−2.02</td><td>38.3</td><td>13.3</td><td>35.01</td><td>3.51</td><td></td><td></td><td>41.96</td><td>24.05</td><td>35.96</td><td>6.31</td></tr><tr><td>C</td><td>3</td><td>3,440.00</td><td>34.27</td><td>32.11</td><td>−6.32</td><td>36.9</td><td>7.6</td><td>33.83</td><td>−1.30</td><td></td><td></td><td>40.29</td><td>17.55</td><td>34.64</td><td>1.08</td></tr><tr><td>C</td><td>2</td><td>3,890.00</td><td>41.22</td><td>42.11</td><td>2.16</td><td>47.7</td><td>15.9</td><td>44.14</td><td>7.09</td><td></td><td></td><td>51.99</td><td>26.13</td><td>44.58</td><td>8.17</td></tr><tr><td>C</td><td>7</td><td>4,030.00</td><td>37.18</td><td>34.56</td><td>−7.04</td><td>41.5</td><td>11.7</td><td>37.08</td><td>−0.28</td><td></td><td></td><td>45.93</td><td>23.53</td><td>37.46</td><td>0.73</td></tr><tr><td>C</td><td>2b</td><td>4,160.00</td><td>50.40</td><td>46.29</td><td>−8.16</td><td>51.9</td><td>2.9</td><td>48.30</td><td>−4.17</td><td></td><td></td><td>56.27</td><td>11.65</td><td>48.48</td><td>−3.81</td></tr><tr><td>Mean</td><td></td><td>3,241.50</td><td>33.90</td><td>31.21</td><td>−8.49</td><td>36.2</td><td>6.5</td><td>33.02</td><td>−3.08</td><td></td><td></td><td>39.69</td><td>16.81</td><td>34.12</td><td>0.64</td></tr><tr><td>SD</td><td></td><td>627.09</td><td>8.49</td><td>8.69</td><td>12.00</td><td>8.8</td><td>8.1</td><td>9.08</td><td>11.99</td><td></td><td></td><td>10.67</td><td>12.82</td><td>8.63</td><td>12.17</td></tr></tbody></table><table-wrap-foot><fn><p>The top half of the table refers to children weighing less than 2 kg (n = 24) and the bottom half those weighing more than 2 kg (n = 10). Study is the reference where the original validation data were published. A is Jensen et al.,<xref rid="bib28" ref-type="bibr"><sup>28</sup></xref> B is Westerterp et al.,<xref rid="bib27" ref-type="bibr"><sup>27</sup></xref> C is Jones et al.,<xref rid="bib32" ref-type="bibr"><sup>32</sup></xref> and D is Roberts et al.<xref rid="bib26" ref-type="bibr"><sup>26</sup></xref> ID is the ID from the original study. BM is the mean body mass of the individual in g. rCO<sub>2</sub> IC is the indirect calorimetry estimate of CO<sub>2</sub> production in liters per day. For each DLW equation, the original data were used to calculate rCO<sub>2</sub> and the % difference between these estimates and the chamber CO<sub>2</sub> production. At the bottom of each part of the table, the summary statistics across all individuals in each sub-group are shown. The summary statistics for <xref rid="fd10" ref-type="disp-formula">Equation 10</xref> refer to the whole sample of n = 34. <xref rid="fd1" ref-type="disp-formula">Equations 1</xref>, <xref rid="fd6" ref-type="disp-formula">6</xref>, <xref rid="fd7" ref-type="disp-formula">7</xref>, and <xref rid="fd10" ref-type="disp-formula">10</xref> refer to the equations derived in the text here. Coward 1985 refers to the two-pool equation in Coward and Prentice.<xref rid="bib22" ref-type="bibr"><sup>22</sup></xref> Speakman 7.17 refers to Equation 7.17 in Speakman,<xref rid="bib3" ref-type="bibr"><sup>3</sup></xref> which is the most widely adopted and validated equation for use in small mammals and birds. For some of the studies, N<sub>d</sub> was not available from the original validations. Because the equation Coward 1985 requires individual estimates of N<sub>d</sub>, a comparison was not possible for these subjects.</p></fn></table-wrap-foot></table-wrap></p><p id="p0130">Using the combination of <xref rid="fd9" ref-type="disp-formula">Equations 9</xref> and <xref rid="fd10" ref-type="disp-formula">10</xref> (or <xref rid="fd11" ref-type="disp-formula">11</xref>) eliminates the boundary discontinuities of using three separate equations and provides a general equation for the estimation of rCO<sub>2</sub> from DLW studies, the adult equation (<xref rid="fd1" ref-type="disp-formula">Equation 1</xref>) being a special case of this more general solution where body mass is greater than 10 kg. A further benefit of this equation combination is that, if more refined analyses in the future result in equations that are better able to predict the DSR, these could be adopted by replacing <xref rid="fd9" ref-type="disp-formula">Equation 9</xref> with an updated prediction model.</p><p id="p0135">We see considerable future benefits in studies using these new equations because they will improve the accuracy of the derived estimates of energy expenditure. Moreover, by having a single equation set that spans all body sizes, it will be easier for researchers to select the best calculation solution to get the most accurate outcomes. Finally, they will enormously facilitate the compilation and comparison of data across different studies. Indeed, we have already prepared a number of manuscripts based on these equations that consider diverse aspects of energy demands, including global aspects of nutrition, energy demands through the lifespan H.P. et al., unpublished data, impacts of physical activity on lean body mass and energy compensation strategies (V. Careau et al., unpublished data; K.R.W. et al., unpublished data, and trends in energy demands over time (J.R.S. et al., unpublished data To facilitate the adoption of these equations, we have also developed a dedicated website that is free to use where users can input isotope data to derive the rCO<sub>2</sub> and TEE using the recommended procedures (<ext-link ext-link-type="uri" xlink:href="http://dlw.som.cuanschutz.edu/" id="intref0015">http://dlw.som.cuanschutz.edu/</ext-link>).</p><p id="p0140">We suggest that future studies using the DLW method should consider adopting a standard approach for calculating rCO<sub>2</sub> and its conversion to TEE. For this purpose, we recommend in adults the equations adopted here (<xref rid="fd1" ref-type="disp-formula">Equation 1</xref> and its calculation forms in <xref rid="fd3" ref-type="disp-formula">Equations 3</xref> and <xref rid="fd4" ref-type="disp-formula">4</xref>) for calculating rCO<sub>2</sub> and the Weir equation for the conversion of rCO<sub>2</sub> to TEE (<xref rid="fd5" ref-type="disp-formula">Equation 5</xref>). This recommendation is based on the performance of the rCO<sub>2</sub> equation in adult validation studies (<xref rid="tbl1" ref-type="table">Table 1</xref>). In babies (<10 kg), we suggest adoption of <xref rid="fd10" ref-type="disp-formula">Equation 10</xref>, where the dilution space ratio is calculated from body weight. This equation performs best in validation studies of babies. Alternatively, if these standards are not adopted, then we suggest users should make available in supplemental materials the values of k<sub>o</sub>, k<sub>d</sub>, N<sub>o</sub>, and N<sub>d</sub> for each individual subject, so that the published estimates can be easily converted to the standard, thereby improving future comparisons. Moreover, we strongly advocate users to upload their DLW data into the IAEA DLW database<xref rid="bib8" ref-type="bibr"><sup>8</sup></xref> and make their standardized data widely available to the scientific community.</p></sec><sec id="sec2.3"><title>Limitations of study</title><p id="p0145">The main advantage of the DLW method is that it allows a measure of free-living energy demands unencumbered by any measurement apparatus. The main advantage of the chamber indirect calorimetry approach is its verified precision and accuracy based on sound physiological and engineering principles. However, chamber calorimetry has the disadvantage that the range of activities that individuals can engage in is more limited than free-living subjects can perform. When the two techniques are brought together in a validation, it is expected because of the restricted activity that the energy expenditure of most subjects would sit at the low end of the spectrum of free-living demands, and hence, the validation may be biased to low levels of expenditure. However, the average CO<sub>2</sub> production across all subjects in the validation study was 497.5 L/day (<xref rid="tbl1" ref-type="table">Table 1</xref>), which is comparable to the expected average CO<sub>2</sub> production of adult free-living individuals weighing 80 kg in the IAEA database of 494 L/day. Hence, this is unlikely to be a serious source of bias. Perhaps the biggest weakness is the fact that, although on average, the new equations perform well at the individual level, there are still considerable discrepancies at the individual level. This variation limits utility of the method to measure individual levels of energy expenditure. The cause of this variation remains unclear and is generally presumed to reflect random errors in isotope enrichment determinations. However, the validation studies have generally not recorded the diets consumed by the subjects. Because, in theory, different dietary constituents may provide different opportunities for hydrogen isotope exchange and may stimulate different levels of <italic>de novo</italic> lipogenesis, this could contribute to isotope dilution spaces and fluxes that are not accounted for in the standard calculation, contributing to the individual discrepancies. Further validation work with individuals consuming known and quantified diets might contribute to lowering this error. As a final word of caution, there are no validation studies for individuals aged >70 years, and the dilution space ratio may decline at older ages.<xref rid="bib20" ref-type="bibr"><sup>20</sup></xref> We suggest <xref rid="fd1" ref-type="disp-formula">Equation 1</xref> should be used in this age group with caution.</p></sec></sec><sec id="sec3"><title>Consortia</title><p id="p0150">This consortia authorship contains the names of people whose data were contributed into the IAEA DLW database by the analysis laboratory, but they later could not be traced or they did not respond to emails to assent inclusion among the authorship. The list also includes some researchers who did not assent inclusion to the main authorship because they felt their contribution was not sufficient to merit authorship: Stefan Branth; Niels C. De Bruin; Lisa H. Colbert; Alice E. Dutman; Simon Eaton; Sölve Elmståhl; Mikael Fogelholm; Tamara Harris; Rik Heijligenberg; Hans U. Jorgensen; Christel L. Larsson; Margaret McCloskey; Gerwin A. Meijer; Daphne L. Pannemans; Renaat M. Philippaerts; John J. Reilly; Elisabet M. Rothenberg; Sabine Schulz; Amy Subar; Minna Tanskanen; Ricardo Uauy; Rita Van den Berg-Emons; Wim G. Van Gemert; Erica J. Velthuis-te Wierik; Wilhelmine W. Verboeket-van de Venne; and Jeanine A. Verbunt.</p></sec><sec id="sec4"><title>STAR★Methods</title><sec id="sec4.1"><title>Key Resources Table</title><p id="p0155"><table-wrap position="float" id="undtbl1"><table frame="hsides" rules="groups"><tbody><tr><td>REAGENT or RESOURCE</td><td>SOURCE</td><td>IDENTIFIER</td></tr><tr><td colspan="3"><hr></hr></td></tr><tr><td colspan="3"><bold>Deposited data</bold></td></tr><tr><td colspan="3"><hr></hr></td></tr><tr><td>The data on which the analyses were based is available in the International Atomic Energy Agency Doubly labeled water database.</td><td>International Atomic Energy Agency</td><td><ext-link ext-link-type="uri" xlink:href="https://www.dlwdatabase.org/" id="intref0020">https://www.dlwdatabase.org/</ext-link></td></tr><tr><td colspan="3"><hr></hr></td></tr><tr><td colspan="3"><bold>Software and algorithms</bold></td></tr><tr><td colspan="3"><hr></hr></td></tr><tr><td>Software for calculating results of DLW experiments</td><td>University of Colorado</td><td><ext-link ext-link-type="uri" xlink:href="http://dlw.som.cuanschutz.edu/" id="intref0025">http://dlw.som.cuanschutz.edu/</ext-link></td></tr></tbody></table></table-wrap></p></sec><sec id="sec4.2"><title>Resource availability</title><sec id="sec4.2.1"><title>Lead contact</title><p id="p0160">Further information and requests for resources and reagents should be directed to and will be fulfilled by the Lead Contact. John R Speakman (<ext-link ext-link-type="uri" xlink:href="mailto:jspeakman@abdn.ac.uk" id="intref0030">jspeakman@abdn.ac.uk</ext-link>)</p></sec><sec id="sec4.2.2"><title>Materials availability</title><p id="p0165">This study did not generate new unique reagents.</p></sec><sec sec-type="data-availability" id="sec4.2.3"><title>Data and code availability</title><p id="p0170">The data presented here pertain to the IAEA DLW database (v3.1) which is a repository of almost 7000 measurements of daily energy expenditure in humans made using the DLW method. Full details of the aims and scope of the database can be found in reference <xref rid="bib8" ref-type="bibr"><sup>8</sup></xref>.</p></sec></sec><sec id="sec4.3"><title>Experimental model and subject details</title><p id="p0175">The analysis here includes data for 5756 children, adolescents and adults and 1021 babies and infants extracted from the IAEA database v3.1. These data have all been published previously and are extracted from relevant publications for inclusion in the database by authors of those papers.</p></sec><sec id="sec4.4"><title>Method details</title><p id="p0180">This study is based on recalculation of previously published data concerning use of the DLW method in free-living subjects and in experiments involving DLW and simultaneous chamber indirect calorimetry. There is no standard approved protocol for the use of the DLW technique and hence studies vary in the exact methods employed. In general however subjects are dosed with <sup>18</sup>Oxygen and deuterium in drinking water at a dose rate aiming to produce an excess enrichment of <sup>18</sup>Oxygen between 150 and 300 ppm above background levels, and an enrichment of deuterium about half that. A background urine sample is taken prior to dosing and an equilibrium sample commonly 3-4 hours afterward (3<sup>rd</sup> void) but in some protocols 10-12h later. The measurement duration can vary between 7 and 21 days and during that period samples may be collected only at the start and end, or on multiple occasions throughout the washout period. Measurement durations are generally shorter for children and dosing can be higher than for adults. The isotope washout is normally calculated from the log converted isotope enrichments above background. When multiple samples are collected it may also be evaluated from a non-linear exponential model fit to the data. Isotope dilution spaces may be calculated from the back extrapolated washout to the dose time, or from the equilibrium samples. During free-living studies individuals continue their daily routines as normal. Full details of the practical aspects of the method can be found in ref <xref rid="bib3" ref-type="bibr"><sup>3</sup></xref>. During chamber validation studies the subjects live continuously or semi-continuously inside a room calorimeter. Semi-continuous occupancy is for 23.5h per day with 30 mins allowed outside for chamber calibration and for subjects to shower. Gas exchange from the chamber is measured using gas analysers and CO<sub>2</sub> production calculated from the difference in CO<sub>2</sub> content between incurrent and excurrent air and the flow rate.</p></sec><sec id="sec4.5"><title>Quantification and statistical analysis</title><p id="p0185">Measurements using different methods were compared in a pairwise fashion using the Bland-Altman methodology<xref rid="bib26" ref-type="bibr"><sup>26</sup></xref>. Comparisons between the simultaneous DLW and chamber respirometry values were made by calculating the absolute differences (precision) and summed differences including the sign (accuracy) between DLW estimates of CO<sub>2</sub> production derived from different equations and the chamber indirect calorimetry estimates.</p></sec></sec></body><back><ref-list id="cebib0010"><title>References</title><ref id="bib1"><label>1</label><element-citation publication-type="journal" id="sref1"><person-group person-group-type="author"><name><surname>Lifson</surname><given-names>N.</given-names></name><name><surname>Gordon</surname><given-names>G.B.</given-names></name><name><surname>McCLINTOCK</surname><given-names>R.</given-names></name></person-group><article-title>Measurement of total carbon dioxide production by means of D2O18</article-title><source>J. Appl. Physiol.</source><volume>7</volume><year>1955</year><fpage>704</fpage><lpage>710</lpage><pub-id pub-id-type="pmid">14381351</pub-id></element-citation></ref><ref id="bib2"><label>2</label><element-citation publication-type="journal" id="sref2"><person-group person-group-type="author"><name><surname>Lifson</surname><given-names>N.</given-names></name></person-group><article-title>Theory of use of the turnover rates of body water for measuring energy and material balance</article-title><source>J. Theor. Biol.</source><volume>12</volume><year>1966</year><fpage>46</fpage><lpage>74</lpage><pub-id pub-id-type="pmid">6015431</pub-id></element-citation></ref><ref id="bib3"><label>3</label><element-citation publication-type="book" id="sref3"><person-group person-group-type="author"><name><surname>Speakman</surname><given-names>J.R.</given-names></name></person-group><chapter-title>Doubly Labelled Water: Theory and Practice</chapter-title><year>1997</year><publisher-name>Chapman and Hall</publisher-name></element-citation></ref><ref id="bib4"><label>4</label><element-citation publication-type="book" id="sref4"><person-group person-group-type="author"><name><surname>Nagy</surname><given-names>K.A.</given-names></name></person-group><chapter-title>The Doubly Labeled Water (3HH18O) Method: A Guide to Its Use</chapter-title><year>1983</year><publisher-name>Laboratory of Biomedical and Environmental Sciences, University of California</publisher-name></element-citation></ref><ref id="bib5"><label>5</label><element-citation publication-type="journal" id="sref5"><person-group person-group-type="author"><name><surname>Schoeller</surname><given-names>D.A.</given-names></name><name><surname>van Santen</surname><given-names>E.</given-names></name></person-group><article-title>Measurement of energy expenditure in humans by doubly labeled water method</article-title><source>J. Appl. Physiol.</source><volume>53</volume><year>1982</year><fpage>955</fpage><lpage>959</lpage><pub-id pub-id-type="pmid">6759491</pub-id></element-citation></ref><ref id="bib6"><label>6</label><element-citation publication-type="journal" id="sref6"><person-group person-group-type="author"><name><surname>Westerterp</surname><given-names>K.R.</given-names></name><name><surname>Saris</surname><given-names>W.H.M.</given-names></name><name><surname>van Es</surname><given-names>M.</given-names></name><name><surname>ten Hoor</surname><given-names>F.</given-names></name></person-group><article-title>Use of the doubly labeled water technique in humans during heavy sustained exercise</article-title><source>J Appl Physiol (1985)</source><volume>61</volume><year>1986</year><fpage>2162</fpage><lpage>2167</lpage><pub-id pub-id-type="pmid">3027022</pub-id></element-citation></ref><ref id="bib7"><label>7</label><element-citation publication-type="journal" id="sref7"><person-group person-group-type="author"><name><surname>Klein</surname><given-names>P.D.</given-names></name><name><surname>James</surname><given-names>W.P.</given-names></name><name><surname>Wong</surname><given-names>W.W.</given-names></name><name><surname>Irving</surname><given-names>C.S.</given-names></name><name><surname>Murgatroyd</surname><given-names>P.R.</given-names></name><name><surname>Cabrera</surname><given-names>M.</given-names></name><name><surname>Dallosso</surname><given-names>H.M.</given-names></name><name><surname>Klein</surname><given-names>E.R.</given-names></name><name><surname>Nichols</surname><given-names>B.L.</given-names></name></person-group><article-title>Calorimetric validation of the doubly-labelled water method for determination of energy expenditure in man</article-title><source>Hum. Nutr. Clin. Nutr.</source><volume>38</volume><year>1984</year><fpage>95</fpage><lpage>106</lpage><pub-id pub-id-type="pmid">6423577</pub-id></element-citation></ref><ref id="bib8"><label>8</label><element-citation publication-type="journal" id="sref8"><person-group person-group-type="author"><name><surname>Speakman</surname><given-names>J.R.</given-names></name><name><surname>Pontzer</surname><given-names>H.</given-names></name><name><surname>Rood</surname><given-names>J.</given-names></name><name><surname>Sagayama</surname><given-names>H.</given-names></name><name><surname>Schoeller</surname><given-names>D.A.</given-names></name><name><surname>Westerterp</surname><given-names>K.R.</given-names></name><name><surname>Wong</surname><given-names>W.W.</given-names></name><name><surname>Yamada</surname><given-names>Y.</given-names></name><name><surname>Loechl</surname><given-names>C.</given-names></name><name><surname>Murphy-Alford</surname><given-names>A.J.</given-names></name></person-group><article-title>The International Atomic Energy Agency International Doubly Labelled Water Database: aims, scope and procedures</article-title><source>Ann. Nutr. Metab.</source><volume>75</volume><year>2019</year><fpage>114</fpage><lpage>118</lpage><pub-id pub-id-type="pmid">31743893</pub-id></element-citation></ref><ref id="bib9"><label>9</label><element-citation publication-type="journal" id="sref9"><person-group person-group-type="author"><name><surname>Dugas</surname><given-names>L.R.</given-names></name><name><surname>Harders</surname><given-names>R.</given-names></name><name><surname>Merrill</surname><given-names>S.</given-names></name><name><surname>Ebersole</surname><given-names>K.</given-names></name><name><surname>Shoham</surname><given-names>D.A.</given-names></name><name><surname>Rush</surname><given-names>E.C.</given-names></name><name><surname>Assah</surname><given-names>F.K.</given-names></name><name><surname>Forrester</surname><given-names>T.</given-names></name><name><surname>Durazo-Arvizu</surname><given-names>R.A.</given-names></name><name><surname>Luke</surname><given-names>A.</given-names></name></person-group><article-title>Energy expenditure in adults living in developing compared with industrialized countries: a meta-analysis of doubly labeled water studies</article-title><source>Am. J. Clin. Nutr.</source><volume>93</volume><year>2011</year><fpage>427</fpage><lpage>441</lpage><pub-id pub-id-type="pmid">21159791</pub-id></element-citation></ref><ref id="bib10"><label>10</label><element-citation publication-type="book" id="sref10"><person-group person-group-type="author"><name><surname>Schoeller</surname><given-names>D.A.</given-names></name><name><surname>Allison</surname><given-names>D.B.</given-names></name></person-group><person-group person-group-type="editor"><name><surname>Schoeller</surname><given-names>D.A.</given-names></name><name><surname>Westerterp-Plantenga</surname><given-names>M.S.</given-names></name></person-group><source>Advances in the Assessment of Dietary Intake</source><year>2017</year><publisher-name>CRC</publisher-name><fpage>185</fpage><lpage>197</lpage><ext-link ext-link-type="uri" xlink:href="https://www.taylorfrancis.com/chapters/use-doubly-labeled-water-measured-energy-expenditure-biomarker-self-reported-energy-intake-dale-schoeller-david-allison/e/10.1201/9781315152288-10?context=ubx&refId=0220c23e-4fce-4b02-88d0-ac0d999dd34a" id="intref0040">Use of doubly-labeled water measured energy expenditure as a biomarker of self-reported energy intake</ext-link></element-citation></ref><ref id="bib11"><label>11</label><element-citation publication-type="book" id="sref11"><person-group person-group-type="author"><collab>International Atomic Energy Agency</collab></person-group><chapter-title>IAEA Human Health Series No. 3. Assessment of Body Composition and Total Energy Expenditure in Humans Using Stable Isotope Techniques</chapter-title><year>2009</year><publisher-name>Vienna International Centre</publisher-name></element-citation></ref><ref id="bib12"><label>12</label><element-citation publication-type="journal" id="sref12"><person-group person-group-type="author"><name><surname>Schoeller</surname><given-names>D.A.</given-names></name><name><surname>Webb</surname><given-names>P.</given-names></name></person-group><article-title>Five-day comparison of the doubly labeled water method with respiratory gas exchange</article-title><source>Am. J. Clin. Nutr.</source><volume>40</volume><year>1984</year><fpage>153</fpage><lpage>158</lpage><pub-id pub-id-type="pmid">6741848</pub-id></element-citation></ref><ref id="bib13"><label>13</label><element-citation publication-type="journal" id="sref13"><person-group person-group-type="author"><name><surname>Westerterp</surname><given-names>K.R.</given-names></name><name><surname>Brouns</surname><given-names>F.</given-names></name><name><surname>Saris</surname><given-names>W.H.</given-names></name><name><surname>ten Hoor</surname><given-names>F.</given-names></name></person-group><article-title>Comparison of doubly labeled water with respirometry at low- and high-activity levels</article-title><source>J. Appl. Physiol.</source><volume>65</volume><year>1988</year><fpage>53</fpage><lpage>56</lpage><pub-id pub-id-type="pmid">3136137</pub-id></element-citation></ref><ref id="bib14"><label>14</label><element-citation publication-type="journal" id="sref14"><person-group person-group-type="author"><name><surname>Seale</surname><given-names>J.L.</given-names></name><name><surname>Conway</surname><given-names>J.M.</given-names></name><name><surname>Canary</surname><given-names>J.J.</given-names></name></person-group><article-title>Seven-day validation of doubly labeled water method using indirect room calorimetry</article-title><source>J Appl Physiol (1985)</source><volume>74</volume><year>1993</year><fpage>402</fpage><lpage>409</lpage><pub-id pub-id-type="pmid">8383108</pub-id></element-citation></ref><ref id="bib15"><label>15</label><element-citation publication-type="journal" id="sref15"><person-group person-group-type="author"><name><surname>Schoeller</surname><given-names>D.A.</given-names></name><name><surname>Ravussin</surname><given-names>E.</given-names></name><name><surname>Schutz</surname><given-names>Y.</given-names></name><name><surname>Acheson</surname><given-names>K.J.</given-names></name><name><surname>Baertschi</surname><given-names>P.</given-names></name><name><surname>Jéquier</surname><given-names>E.</given-names></name></person-group><article-title>Energy expenditure by doubly labeled water: validation in humans and proposed calculation</article-title><source>Am. J. Physiol.</source><volume>250</volume><year>1986</year><fpage>R823</fpage><lpage>R830</lpage><pub-id pub-id-type="pmid">3085521</pub-id></element-citation></ref><ref id="bib16"><label>16</label><element-citation publication-type="journal" id="sref16"><person-group person-group-type="author"><name><surname>Ravussin</surname><given-names>E.</given-names></name><name><surname>Harper</surname><given-names>I.T.</given-names></name><name><surname>Rising</surname><given-names>R.</given-names></name><name><surname>Bogardus</surname><given-names>C.</given-names></name></person-group><article-title>Energy expenditure by doubly labeled water: validation in lean and obese subjects</article-title><source>Am. J. Physiol.</source><volume>261</volume><year>1991</year><fpage>E402</fpage><lpage>E409</lpage><pub-id pub-id-type="pmid">1909495</pub-id></element-citation></ref><ref id="bib17"><label>17</label><element-citation publication-type="journal" id="sref17"><person-group person-group-type="author"><name><surname>Melanson</surname><given-names>E.L.</given-names></name><name><surname>Swibas</surname><given-names>T.</given-names></name><name><surname>Kohrt</surname><given-names>W.M.</given-names></name><name><surname>Catenacci</surname><given-names>V.A.</given-names></name><name><surname>Creasy</surname><given-names>S.A.</given-names></name><name><surname>Plasqui</surname><given-names>G.</given-names></name><name><surname>Wouters</surname><given-names>L.</given-names></name><name><surname>Speakman</surname><given-names>J.R.</given-names></name><name><surname>Berman</surname><given-names>E.S.F.</given-names></name></person-group><article-title>Validation of the doubly labeled water method using off-axis integrated cavity output spectroscopy and isotope ratio mass spectrometry</article-title><source>Am. J. Physiol. Endocrinol. Metab.</source><volume>314</volume><year>2018</year><fpage>E124</fpage><lpage>E130</lpage><pub-id pub-id-type="pmid">28978547</pub-id></element-citation></ref><ref id="bib18"><label>18</label><element-citation publication-type="journal" id="sref18"><person-group person-group-type="author"><name><surname>Schoeller</surname><given-names>D.A.</given-names></name></person-group><article-title>Measurement of energy expenditure in free-living humans by using doubly labeled water</article-title><source>J. Nutr.</source><volume>118</volume><year>1988</year><fpage>1278</fpage><lpage>1289</lpage><pub-id pub-id-type="pmid">3142975</pub-id></element-citation></ref><ref id="bib19"><label>19</label><element-citation publication-type="journal" id="sref19"><person-group person-group-type="author"><name><surname>Racette</surname><given-names>S.B.</given-names></name><name><surname>Schoeller</surname><given-names>D.A.</given-names></name><name><surname>Luke</surname><given-names>A.H.</given-names></name><name><surname>Shay</surname><given-names>K.</given-names></name><name><surname>Hnilicka</surname><given-names>J.</given-names></name><name><surname>Kushner</surname><given-names>R.F.</given-names></name></person-group><article-title>Relative dilution spaces of 2H- and 18O-labeled water in humans</article-title><source>Am. J. Physiol.</source><volume>267</volume><year>1994</year><fpage>E585</fpage><lpage>E590</lpage><pub-id pub-id-type="pmid">7943308</pub-id></element-citation></ref><ref id="bib20"><label>20</label><element-citation publication-type="journal" id="sref20"><person-group person-group-type="author"><name><surname>Sagayama</surname><given-names>H.</given-names></name><name><surname>Yamada</surname><given-names>Y.</given-names></name><name><surname>Racine</surname><given-names>N.M.</given-names></name><name><surname>Shriver</surname><given-names>T.C.</given-names></name><name><surname>Schoeller</surname><given-names>D.A.</given-names></name><collab>DLW Study Group</collab></person-group><article-title>Dilution space ratio of 2H and 18O of doubly labeled water method in humans</article-title><source>J Appl Physiol (1985)</source><volume>120</volume><year>2016</year><fpage>1349</fpage><lpage>1354</lpage><pub-id pub-id-type="pmid">26989221</pub-id></element-citation></ref><ref id="bib21"><label>21</label><element-citation publication-type="journal" id="sref21"><person-group person-group-type="author"><name><surname>Speakman</surname><given-names>J.R.</given-names></name><name><surname>Nair</surname><given-names>K.S.</given-names></name><name><surname>Goran</surname><given-names>M.I.</given-names></name></person-group><article-title>Revised equations for calculating CO2 production from doubly labeled water in humans</article-title><source>Am. J. Physiol.</source><volume>264</volume><year>1993</year><fpage>E912</fpage><lpage>E917</lpage><pub-id pub-id-type="pmid">8333517</pub-id></element-citation></ref><ref id="bib22"><label>22</label><element-citation publication-type="journal" id="sref22"><person-group person-group-type="author"><name><surname>Coward</surname><given-names>W.A.</given-names></name><name><surname>Prentice</surname><given-names>A.M.</given-names></name></person-group><article-title>Isotope method for the measurement of carbon dioxide production rate in man</article-title><source>Am. J. Clin. Nutr.</source><volume>41</volume><year>1985</year><fpage>659</fpage><lpage>663</lpage><pub-id pub-id-type="pmid">3919561</pub-id></element-citation></ref><ref id="bib23"><label>23</label><element-citation publication-type="book" id="sref23"><person-group person-group-type="author"><name><surname>Shanthini</surname><given-names>R.</given-names></name></person-group><chapter-title>Working with ideal gas</chapter-title><source>Thermodynamics for Beginners with Worked Examples</source><year>2006</year><publisher-name>Peradeniya University</publisher-name><publisher-loc>Peradeniya, Sri Lanka</publisher-loc><fpage>35</fpage><lpage>68</lpage></element-citation></ref><ref id="bib24"><label>24</label><element-citation publication-type="journal" id="sref24"><person-group person-group-type="author"><name><surname>Weir</surname><given-names>J.B.</given-names></name></person-group><article-title>New methods for calculating metabolic rate with special reference to protein metabolism</article-title><source>J. Physiol.</source><volume>109</volume><year>1949</year><fpage>1</fpage><lpage>9</lpage><pub-id pub-id-type="pmid">15394301</pub-id></element-citation></ref><ref id="bib25"><label>25</label><element-citation publication-type="journal" id="sref25"><person-group person-group-type="author"><name><surname>Bland</surname><given-names>J.M.</given-names></name><name><surname>Altman</surname><given-names>D.G.</given-names></name></person-group><article-title>Statistical methods for assessing agreement between two methods of clinical measurement</article-title><source>Lancet</source><volume>1</volume><year>1986</year><fpage>307</fpage><lpage>310</lpage><pub-id pub-id-type="pmid">2868172</pub-id></element-citation></ref><ref id="bib26"><label>26</label><element-citation publication-type="journal" id="sref26"><person-group person-group-type="author"><name><surname>Wells</surname><given-names>J.C.</given-names></name><name><surname>Ritz</surname><given-names>P.</given-names></name><name><surname>Davies</surname><given-names>P.S.</given-names></name><name><surname>Coward</surname><given-names>W.A.</given-names></name></person-group><article-title>Factors affecting the 2H to 18O dilution space ratio in infants</article-title><source>Pediatr. Res.</source><volume>43</volume><year>1998</year><fpage>467</fpage><lpage>471</lpage><pub-id pub-id-type="pmid">9544999</pub-id></element-citation></ref><ref id="bib27"><label>27</label><element-citation publication-type="journal" id="sref27"><person-group person-group-type="author"><name><surname>Roberts</surname><given-names>S.B.</given-names></name><name><surname>Coward</surname><given-names>W.A.</given-names></name><name><surname>Schlingenseipen</surname><given-names>K.H.</given-names></name><name><surname>Nohria</surname><given-names>V.</given-names></name><name><surname>Lucas</surname><given-names>A.</given-names></name></person-group><article-title>Comparison of the doubly labeled water (2H2(18)O) method with indirect calorimetry and a nutrient-balance study for simultaneous determination of energy expenditure, water intake, and metabolizable energy intake in preterm infants</article-title><source>Am. J. Clin. Nutr.</source><volume>44</volume><year>1986</year><fpage>315</fpage><lpage>322</lpage><pub-id pub-id-type="pmid">3092629</pub-id></element-citation></ref><ref id="bib28"><label>28</label><element-citation publication-type="journal" id="sref28"><person-group person-group-type="author"><name><surname>Westerterp</surname><given-names>K.R.</given-names></name><name><surname>Lafeber</surname><given-names>H.N.</given-names></name><name><surname>Sulkers</surname><given-names>E.J.</given-names></name><name><surname>Sauer</surname><given-names>P.J.J.</given-names></name></person-group><article-title>Comparison of short term indirect calorimetry and doubly labeled water method for the assessment of energy expenditure in preterm infants</article-title><source>Biol. Neonate</source><volume>60</volume><year>1991</year><fpage>75</fpage><lpage>82</lpage></element-citation></ref><ref id="bib29"><label>29</label><element-citation publication-type="journal" id="sref29"><person-group person-group-type="author"><name><surname>Jensen</surname><given-names>C.L.</given-names></name><name><surname>Butte</surname><given-names>N.F.</given-names></name><name><surname>Wong</surname><given-names>W.W.</given-names></name><name><surname>Moon</surname><given-names>J.K.</given-names></name></person-group><article-title>Determining energy expenditure in preterm infants: comparison of 2H(2)18O method and indirect calorimetry</article-title><source>Am. J. Physiol.</source><volume>263</volume><year>1992</year><fpage>R685</fpage><lpage>R692</lpage><pub-id pub-id-type="pmid">1415659</pub-id></element-citation></ref><ref id="bib30"><label>30</label><element-citation publication-type="journal" id="sref30"><person-group person-group-type="author"><name><surname>Ritz</surname><given-names>P.</given-names></name><name><surname>Johnson</surname><given-names>P.G.</given-names></name><name><surname>Coward</surname><given-names>W.A.</given-names></name></person-group><article-title>Measurements of <sup>2</sup>H and <sup>18</sup>O in body water: analytical considerations and physiological implications</article-title><source>Br. J. Nutr.</source><volume>72</volume><year>1994</year><fpage>3</fpage><lpage>12</lpage><pub-id pub-id-type="pmid">7918326</pub-id></element-citation></ref><ref id="bib31"><label>31</label><element-citation publication-type="journal" id="sref31"><person-group person-group-type="author"><name><surname>de Bruin</surname><given-names>N.C.</given-names></name><name><surname>Degenhart</surname><given-names>H.J.</given-names></name><name><surname>Gàl</surname><given-names>S.</given-names></name><name><surname>Westerterp</surname><given-names>K.R.</given-names></name><name><surname>Stijnen</surname><given-names>T.</given-names></name><name><surname>Visser</surname><given-names>H.K.</given-names></name></person-group><article-title>Energy utilization and growth in breast-fed and formula-fed infants measured prospectively during the first year of life</article-title><source>Am. J. Clin. Nutr.</source><volume>67</volume><year>1998</year><fpage>885</fpage><lpage>896</lpage><pub-id pub-id-type="pmid">9583846</pub-id></element-citation></ref><ref id="bib32"><label>32</label><element-citation publication-type="journal" id="sref32"><person-group person-group-type="author"><name><surname>Jones</surname><given-names>P.J.H.</given-names></name><name><surname>Winthrop</surname><given-names>A.L.</given-names></name><name><surname>Schoeller</surname><given-names>D.A.</given-names></name><name><surname>Swyer</surname><given-names>P.R.</given-names></name><name><surname>Smith</surname><given-names>J.</given-names></name><name><surname>Filler</surname><given-names>R.M.</given-names></name><name><surname>Heim</surname><given-names>T.</given-names></name></person-group><article-title>Validation of doubly labeled water for assessing energy expenditure in infants</article-title><source>Pediatr. Res.</source><volume>21</volume><year>1987</year><fpage>242</fpage><lpage>246</lpage><pub-id pub-id-type="pmid">3104873</pub-id></element-citation></ref><ref id="bib33"><label>33</label><element-citation publication-type="journal" id="sref33"><person-group person-group-type="author"><name><surname>Speakman</surname><given-names>J.R.</given-names></name></person-group><article-title>How should we calculate CO<sub>2</sub> production in doubly labeled water studies of animals?</article-title><source>Funct. Ecol.</source><volume>7</volume><year>1993</year><fpage>746</fpage><lpage>750</lpage></element-citation></ref></ref-list><ack id="ack0010"><title>Acknowledgments</title><p id="p0190">The DLW database, which can be found at <ext-link ext-link-type="uri" xlink:href="https://www.dlwdatabase.org/" id="intref0035">https://www.dlwdatabase.org/</ext-link>, is generously supported by the <funding-source id="gs1"><institution-wrap><institution-id institution-id-type="doi">10.13039/501100004493</institution-id><institution>IAEA (Vienna, Austria)</institution></institution-wrap></funding-source>, <funding-source id="gs2">Taiyo Nippon Sanso</funding-source>, and <funding-source id="gs3">SERCON</funding-source>. We are grateful to these companies for their support and especially to Takashi Oono for his tremendous efforts at fund raising on our behalf. The authors also gratefully acknowledge funding from the <funding-source id="gs4">US National Science Foundation</funding-source> (BCS-1824466) awarded to Herman Pontzer. The funders played no role in the content of this manuscript.</p><sec id="sec5"><title>Author contributions</title><p id="p0195">J.R.S., Y.Y., D.A.S., H.S., W.W.W., A.H.L., J.R., K.R.W., H.P., C.U.L., and A.J.M.-A. conceived the study. J.R.S., Y.Y., and H.S. performed the calculations, analyzed the data, and derived the equations. E.S.F.B., S.A.C., and E.L.M. programmed the website to perform the calculations. All the other authors contributed data to the analysis. J.R.S. wrote the first draft. All authors contributed to the manuscript and assented to submission.</p></sec><sec sec-type="COI-statement" id="sec6"><title>Declaration of interests</title><p id="p0200">The authors declare no competing interests.</p></sec></ack></back></pmc></record>Pour manipuler ce document sous Unix (Dilib)
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