Pontzer and his colleagues’ research showed that the number of calories burned in a typical day by a member of the Hadza, a hunter-gatherer tribe in Tanzania, was indistinguishable from that burned by a typical adult from Europe or the United States. This is despite the miles of hilly terrain covered by Hadza women while gathering and Hadza men while hunting. The reason the Hadza consume no additional calories in total is because they expend less energy in other areas, such as the background rate of metabolism.
The odd thing about Pontzer’s NYT article is the title “Debunking the Hunter-Gatherer Workout”. If Pontzer spent some time on the various hunter-gatherer and paleo websites, he would quickly discover that the typical paleo workout is not based upon burning more calories, but is framed around a fractal pattern of exercise – brief moments of great exertion, longer periods of moderate exercise such as walking, and lots of rest – roughly like the Hadza lifestyle.
Razib at Gene Expression also makes an interesting point about the paper:
I checked over their references, and the authors don’t note the rather numerous studies since the mid-2000s which indicate that metabolism has been one of the major targets for natural selection in the Holocene (last 10,000 years). For example, Adaptations to Climate-Mediated Selective Pressures in Humans, or, Adaptations to climate in candidate genes for common metabolic disorders. If I had to bet I think the authors of the PLoS ONE paper are on to something, but they need to be careful to generalize from the Hadza, Western populations. In fact, I would be very curious to see a similar survey of the Bushmen of South Africa, and the Pygmies of the Congo. Probably the results would be the same, but it would still be informative to check to see if in fact these deeply diverged human lineages tended toward the same metabolic housekeeping and accounting. If so, then that might be the ancestral state.
As I recently posted about, we may still reflect our ancestral state, but recent human evolution means that it should not be assumed.