Much has been made of late about exercise and its relation to weight loss. There was the Time cover story The Myth About Weight Loss and a recent article on the topic in the New York Times, which recommended working out in the fat burning zone.You see the phrase on all types of cardio machines: the fat burning zone, aka the "weight loss zone," means working out at a lower intensity to burn fat as fuel. But these workouts also burn considerably fewer calories. I was confused about how we should all be spending our cardio time, so I took my questions to exercise physiologist Jason Karp, who also happens to be an avid runner.
When I asked him if we should all be scaling our workouts back and aiming for the fat burning zone, Karp explained that it's not the type of fuel your body is burning, but the overall calories that count. "It doesn't matter if you're using fat or carbohydrates. In order to lose fat from your waistline you don't have to be using fat as fuel during workout," he said. He offered up the example of sprinters; they don't train in the fat burning zone, but they're mighty trim in the torso. Losing weight comes down to math — you want to be in a calorie deficit to shed pounds and body fat. Higher intensity exercise puts you at a higher burn rate. To burn the most calories in a cardio workout, skip past the fat burning zone and work out with more intensity. To really burn up calories, Karp recommends intervals. To learn why, read more