If you’re the kind of exerciser who constantly checks your heart rate to ensure you’re in the “fat-burning zone,” you’re misleading yourself. There’s no such special zone that’s key to getting lean. It’s a myth.
Yes, we know. If you look at the wall charts posted by many personal trainers, you’ll be indoctrinated about the fat-burning zone. The standard advice for getting in this zone is to work out at about 60 percent of your maximum heart rate. Working in this zone, it’s said, will burn more fat and result in greater long-term weight loss, compared with doing the same exercise at higher intensities.
There’s substance to part of this claim. Your body primarily fuels itself by burning a mix of stored fat and carbohydrates. It’s true that at some lower workout intensities, you’re burning a higher percentage of fat than at other intensities. But that doesn’t mean this biological process is the key to losing weight from exercise.
Experts explain that those who believe in a lard-melting zone are forgetting about calories. Although it might sound better for weight loss to burn a higher percentage of fat, the real-world effect of that intensity on your body composition is next to nil.
“The idea that all of a sudden when you hit this zone the fat is just being sucked out of your system is simplistic,” said Christopher Breen, an exercise physiologist and online coach in New York City. “That completely ignores that losing or maintaining weight is basically a matter of calories in versus calories out.”
Christine Brooks, a University of Florida adjunct instructor and coaching science coordinator for USA Track & Field, shares Breen’s concerns about the faddish nature of fat-burning zones.
“I have a real beef with the way this fat-burning idea is promoted,” Brooks said. “It’s a very strange way to talk about exercise.” She and Breen agree that the myth persists because it’s an easy concept to grasp. “It’s a way of making exercise machines more appealing — if I’m working at this speed, I’ll burn more fat than at another speed,” Breen said.
None of this is to suggest that any exercise is a waste of time.
“Mix it up,” Breen said about structuring your workouts. “Have some harder, high-intensity days, followed by easier, low-intensity recovery days.”
Also aim for different durations. When you have the time, do longer workouts at a comfortable level of effort. When you’re pressed for time, work a little harder.
Variety in your workouts will keep you fresher physically and mentally than if you do the same thing day after day after day. That freshness will make it more likely that you exercise consistently. And that’s the zone that will result in long-term weight loss.