Your Best Way To Lose Fat

For some, exercise might not be the magic ticket to weight loss. Here’s why – and what to do about it.

- Lou Schuler

For decades, the experts’ line on exercise and weight loss was simple: do this much, lose that much. But recently they’ve changed their tune: while exercise is awesome for overall physical and mental health, they say, don’t expect it to necessarily yield the number-one result most guys want when they join a gym.

Why the switch? More than anything, it comes down to Hadza piss.

The Hadza are hunter-gatherers in East Africa who get more exercise in a day than many of us get in a week. When scientists set out to measure the caloric cost of all that hunting and gathering (plus everything else requiring energy), they got the Hadza to drink water laced with two rare isotopes. After checking the peed-out isotopes and comparing the ratio of one to the other, they could tell how much CO2 the Hadzas produced during that time; and by extension, how many overall kilojoules they’d burned.

“I came into this research assuming that the more activity you get, the more kilojoules you burn,” says Professor Herman Pontzer, an anthropologist at Hunter College and one of the architects of this paradigm-changing research. He’d also assumed the converse – that the more time you spend sitting, the fewer kilojoules you burn. So when he conducted a pissing match between the lean-and-hungry Hadza and sedentary office workers, the results shocked him. After accounting for body size, the office slugs had the same energy expenditure as guys who chase giraffes for a living.

Pontzer says it’s the same across species. The daily kilojoule burn of a caged zoo animal is the same as that of its born-free counterpart in the Serengeti. Apparently the more active you are, the more your metabolism adjusts to balance the caloric ledger.