Pontzer, H., D. A. Raichlen, et al. (2012). “Hunter-Gatherer Energetics and Human Obesity.” PLoS ONE 7(7): e40503 (open access)
Western lifestyles differ markedly from those of our hunter-gatherer ancestors, and these differences in diet and activity level are often implicated in the global obesity pandemic. However, few physiological data for hunter-gatherer populations are available to test these models of obesity. In this study, we used the doubly-labeled water method to measure total daily energy expenditure (kCal/day) in Hadza hunter-gatherers to test whether foragers expend more energy each day than their Western counterparts. As expected, physical activity level, PAL, was greater among Hadza foragers than among Westerners. Nonetheless, average daily energy expenditure of traditional Hadza foragers was no different than that of Westerners after controlling for body size. The metabolic cost of walking (kcal kg−1 m−1) and resting (kcal kg−1 s−1) were also similar among Hadza and Western groups. The similarity in metabolic rates across a broad range of cultures challenges current models of obesity suggesting that Western lifestyles lead to decreased energy expenditure. We hypothesize that human daily energy expenditure may be an evolved physiological trait largely independent of cultural differences.
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The study indicates the similar TEE for one small group compared to whom in a market economy? This study appears to indicate that specific physical activities among dissimilar populations of humans have similar metabolic requirements. However, what are the average daily caloric intakes of these groups? Did The Hadza have an intake equivalent to the TEE? Do obese populations have an intake that exceeds their TEE. Did you collect the perspiration from these people who live in a tropical environment to determine the energy used for thermoregulation? What is the avg. daily temp during your experiments. What were the ambient conditions of the Westerners. Was their environment indoors and regulated and their energy subsidized by HVAC? Perhaps it would be more germane to directly compare individuals defined as obese in western communities such as the San Gabriel and Pomona Valleys in CA that do very little walking to those westerners in communities where walking is a vital part of their daily routine.