Scientists Find New Obesity Clue in Tanzania

Scientists have long thought our hunter-gatherer ancestors burned through many more calories than the TV-watching, desk-sitting people of today, but a new study suggests that may not be the case—and the finding could inform our very modern-day battle against obesity. Researchers studied 30 members of the still-hunter-gatherer Hadza tribe of Tanzania, and compared their metabolic rate to that of Westerners. Though the Hadza were far more active, their metabolic rate—the amount of energy they expend in a given time—was essentially the same as that of Westerners, reports the BBC.

"This to me says that the big reason that Westerners are getting fat is because we eat too much—it's not because we exercise too little," said one of the scientists behind the study. "Daily energy expenditure might be an evolved trait that has been shaped by evolution and is common among all people and not some simple reflection of our diverse lifestyles." Still, he pointed out that the study isn't a green light to ignore exercise. "Being active is really important to your health but it won't keep you thin—we need to eat less to do that." (More obesity epidemic stories.)