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Low physical activity levels of modern Homo sapiens among free-ranging mammals


Obesity prevalence rates are increasing worldwide and one prevailing hypothesis is that physical activity levels of modern humans are markedly reduced compared to those of our Paleolithic ancestors. We examine this hypothesis by deriving relative activity energy expenditure from available doubly labeled water and indirect calorimetry data in free-ranging non-human mammals. Our results, given the constraints posed by limited data availability, suggest that a low physical activity level, much less than that observed in free-ranging non-human mammals or highly active humans, is present in modern adult humans living within advanced settings. Our observations lend support to the hypothesis that low activity-related energy expenditure levels contribute to the rising worldwide prevalence of obesity.

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  1. WHO. Obesity: Preventing and managing the global epidemic. Report of a WHO consultation on obesity, 3–5 June 1997. World Health Organization, Geneva, Switzerland; 1998.

  2. Prentice AM, Jebb SA . Obesity in Britain: Gluttony or sloth? BMJ 1995; 311: 437–439.

    Article  CAS  Google Scholar 

  3. Blundell JE, Cooling J . Routes to obesity: phenotypes, food choices and activity. Br J Nutr 2000; 83: S33–S38.

    Article  CAS  Google Scholar 

  4. Calder III WA . Size, function, and life history. Dover Publications, Inc.: New York; 1996.

    Google Scholar 

  5. Bishop CT . Wildlife feeding and nutrition, 2nd edn. Academic Press: San Diego; 1993.

    Google Scholar 

  6. Westerterp KR . Limits to sustainable human metabolic rate. J Exp Biol 2001; 204: 3183–3187.

    CAS  PubMed  Google Scholar 

  7. Speakman J . Factors influencing the daily energy expenditure of small mammals. Proc Nutr Soc 1997; 56: 1119–1136.

    Article  CAS  Google Scholar 

  8. Leonard WR, Robertson ML . Nutritional requirements and human evolution: a bioenergetics model. Am J Hum Biol 1992; 4: 179–195.

    Article  Google Scholar 

  9. Katzmarzyk PT, Leonard WR, Crawford MH, Sukernik RI . Resting metabolic rate and daily energy expenditure among two indigenous Siberian populations. Am J Hum Biol 1994; 6: 719–730.

    Article  CAS  Google Scholar 

  10. Leonard WR . Food for thought. Dietary change was a driving force in human evolution. Sci Am 2002; 287: 106–115.

    Article  Google Scholar 

  11. Sorensen MV, Leonard WR . Neandertal energetics and foraging efficiency. J Hum Evol. 2001; 40: 483–495.

    Article  CAS  Google Scholar 

  12. Eaton SB, Konner M, Shostak M . Stone agers in the fast lane: chronic degenerative diseases in evolutionary perspective. Am J Med 1988; 84: 739–749.

    Article  CAS  Google Scholar 

  13. Panter-Brick C . Sexual division of labor: energetic and evolutionary scenarios. Am J Hum Biol 2002; 14: 627–640.

    Article  Google Scholar 

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We acknowledge the new primate doubly labeled water data generously provided by Jeanne and Stuart Altmann of Princeton University.

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Correspondence to S B Heymsfield.

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Supported by National Institutes of Health Grant RO1-NIDDK 42618.


Appendix and table references


Speakman J. Factors influencing the daily energy expenditure of small mammals. Proc Nutr Soc 1997; 56: 1119–1136.


Nagy KA, Girard IA, Brown TK. Energetics of free-ranging mammals, reptiles and birds. Field Metabolism Scaling 1999; 19: 247–277.


Pappenheimer JR. Scaling of dimensions of small intestines in non-ruminant eutherian mammals and its significance for absorptive mechanisms. Comp Biochem Physiol 1998; 21: (Part A) 45–58.


Kleiber M. The fire of life: an introduction to animal energetics, Chapter 10. John Wiley & Sons: New York; 1961. pp 177–216.


Alexander RM. Energy for animal life, Chapter 2. Oxford University Press: Oxford; 1999. pp 22–42.


Hammond KA, Diamond J. Maximal sustained energy budgets in humans and animals. Nature 1997; 386: 457–462.


Prentice AM, Black AE, Coward WA, Cole TJ. Energy expenditure in overweight and obese adults in affluent societies: an analysis of 319 doubly-labeled water measurements. Eur J Clin Nutr 1996; 50: 93–97.


Esparaza J, Fox C, Harper IT, Bennett PH, Schulz LO, Valencia ME, Ravussin E. Daily energy expenditure in Mexico and USA Pima Indians: low physical activity as a possible cause of obesity. Intl J Obes 2000; 24: 55–59.


Singh J, Prentice AM, Diaz E, Coward WA, Ashford J, Sawyer M, Whitehead RG. Energy expenditure of Gambian women during peak agricultural activity measured by the doubly-labeled water method. Br J Nutr 1989; 62: 315–329.


Heini AF, Minghelli G, Diaz E, Prentice AM, Schutz Y. Free-living energy expenditure assessed by two different methods in rural Gambian men. Eur J Clin Nutr 1996; 50: 284–289.


Diaz E, Goldberg GR, Taylor M, Savage JM, Sellen D, Coward WA, Prentice AM. Effects of dietary supplementation on work performance in Gambian laborers. Am J Clin Nutr 1991; 53: 803–811.


Burstein R, Coward AW, Askew WE, Carmel K, Irving C, Shpilberg O, Moran D, Pikarsky A, Ginot G, Sawyer M, Golan R, Epstein Y. Energy expenditure variations in soldiers performing military activities under cold and hot climate conditions. Mil Med 1996; 161: 750–754.


Hoyt RW, Jones TE, Stein TP, McAninch BW, Lieberman HR, Askew EW, Cymerman A. Doubly labeled water measurements of human energy expenditure during strenuous exercise. J Appl Physiol 1991; 71: 16–22.


DeLany JP, Scholeeler DA, Hoyt RW, Askew EW, Sharp MA. Field use in D2 18O to measure energy expenditure of soldiers at different energy intakes. J Appl Physiol 1989; 67: 1922–1929.


Jones PJH, Jacobs I, Morris A, Ducharme MB. Adequacy of food rations in soldiers during an arctic exercise measured by doubly labeled water. J Appl Physiol 1993; 75: 1790–1797.


Forbes-Ewan CH, Morrissey BLL, Gregg GC, Waters DR. Use of doubly labeled water technique in soldiers training for jungle warfare. J Appl Physiol 1989; 67: 14–18.


Schulz LO, Alger S, Harper I, Wilmore JH, Ravussin E. Energy expenditure of elite female runners measured by respiratory chamber and doubly labeled water. J Appl Physiol 1992; 72: 23–28.


Black AE, Coward WA, Cole TJ, Prentice AM. Human Energy expenditure in affluent societies: an analysis of 574 doubly-labeled water measurements. Eur J Clin Nutr 1996; 50: 72–92.


Trappe TA, Gastaldelli A, Jozsi AC, Troup JP, Wolfe RR. Energy expenditure of swimmers during high volume training. Med Sci Sports Exer 1997; 29: 950–954.


Westerterp KR, Kayser B, Brouns F, Herry JP, Saris WHM. Energy expenditure climbing Mt. Everest. J Appl Physiol 1992; 73: 1815–1819.


Sjodin AM, Andersson AB, Hogberg JM, Westerterp KR. Energy balance in cross-country skiers: a study using doubly labeled water. Med Sci Sports Exer 1994; 26: 720–724.

Appendix A1

Free-ranging expenditure was evaluated using a composite database developed from previously reported and new doubly labeled water human and animal studies (see Table A1).

Table A1 Field and resting energy expenditure data in mammals

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Hayes, M., Chustek, M., Heshka, S. et al. Low physical activity levels of modern Homo sapiens among free-ranging mammals. Int J Obes 29, 151–156 (2005).

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