As any office drone who reads the Internet knows, sitting too much will make you depressed and eventually kill you. Also it'll probably make you fat. Hence the popularity of fads like the paleo diet and other caveman fitness trends. But huh, maybe office wage slaves are burning off more energy than we thought?
A new study compares the energy expenditure of hunter gatherers (specifically the Hazda, a hunter-gatherer population in Northern Tanzania) with those of more sedentary Westerners and, as they say, the results may surprise you. "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."
So yeah, our sedentary lifestyles may not actually result in abnormally low energy expenditures. So why are Westerners so fat? Because we eat too much highly-processed, energy-dense but nutrient-poor foods. If we'd just eat a little better, we too could have the lean bodies of hunter gatherers without all the hunting and gathering.
Or maybe not? As the study points out "Physical activity has important, positive effects on health, and increased physical activity has been shown to play an important role in weight loss and weight-maintenance programs. Some studies of self-reported activity level have even suggested that habitual activity may help prevent unhealthy weight gain, although the evidence is mixed." So. Probably best to still try and get up and shake your legs every hour or so!