The answer must be burning calories.
But, that would be wrong.
The hunter-gatherer Hadza tibemen studied, although more active than Westerners, expended no more energy than those who are sedentary.
Although it is tempting to use simple math when trying to manage weight, it seems that processed, genetically modified food have an incalculable negative on human biology and weight maintenance.
So, if you are not hunting for your food on a daily basis, the next best thing is to eat simple, seasonal, unadulterated whole foods in their natural form.
Not surprisingly, the Hadza were more physically active than Westerners. However, they didn’t expend more energy. The Hadza’s average daily energy expenditure was no different than that of Westerners, after controlling for body size, the analysis found.
“We hypothesize that human daily energy expenditure may be an evolved physiological trait largely independent of cultural differences,” they write.
Unlike a growing portion of the Westernized world, however, the Hadza are lean. This suggests obesity rates in Westernized countries stem from differences in energy intake — meaning more rich food than our human ancestors ate, they conclude.