This isn’t the first study to look at how brown fat works. Research published earlier this year discovered that exposure to mildly cold temperatures also spurs brown fat production and helps the body burn more calories in an attempt to produce heat and stay warm. But now, experts know where brown fat actually comes from in the first place. “It’s actually eating that encourages white fat to turn brown. If you eat, you promote heat production,” says lead study author Xiaoyong Yang, PhD.
From an evolutionary standpoint, this makes a lot of sense. If food is scarce—as it often was during the caveman days—your body burns fewer calories to save valuable energy. Once food becomes abundant and you start eating more, the calorie-burning can pick up, too.
The question, of course, is how to find the right balance between eating enough to encourage fat-browning, but not so much that you gain weight. So far experts can’t offer a magic number of calories to aim for, since more research is needed to see how hunger and appetite cause white fat to brown in humans. Still, it’s probably not a bad idea to nix behaviors like overeating followed by crash dieting. “Those habits could wear out your brain’s capacity to control fat burning,” Yang says. And nobody wants that, right?
