We are told that our western lifetyle is to blame and that all we need to eat less and move more. And that sounds intuitively true. The move more part was challenged by a study of the Hadza people (Pontzer H, Raichlen DA, Wood BM, Mabulla AZP, Racette SB, et al. (2012) Hunter-Gatherer Energetics and Human Obesity. PLOS ONE 7(7): e40503.).
…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.
Interesting article (What a hunter-gatherer diet does to the body in just three days).
My other lasting impression was how little time they spent getting food. It appeared as though it took just a few hours a day — as simple as going round a large supermarket. Any direction you walked there was food — above, on and below ground.