Good Advice
Is the fat-burning zone a fitness myth?
It’s cold outside. And as the temperature dips, many New Yorkers head indoors to work out, trading the soupy city streets for a treadmill or stationary bike. And that’s where many of us encounter a puzzling (and often dated-looking) diagram pointing out the so-called “fat-burning zone.”
The reason it’s plastered all over the gym? Proponents of the zone argue that it represents a kind of exercise sweet spot—typically between 60 and 70 percent of our maximum heart rate—in which our bodies burn the most fat.
So should we buy into the idea?
In a word—no.
On average, when we’re resting, 60 percent of the energy we use for fuel comes from fat, 35 percent comes from carbohydrates, and the remaining five percent comes from protein. But when we exercise, our bodies begin burning more carbohydrates to fuel our activity, and less fat. All of which has led some to argue that we should work out at lower intensities to trick our bodies into using more fat as fuel.
Feel free to watch TV at the gym: This popular chart may not be worth your time and attention
Unfortunately, that’s not true.
“The practical way most people think about the fat-burning zone is that they’re using more fat to fuel their exercise and therefore, they’re going to lose more body fat,” says Dr. Karen Reznik Dolins, a professor of nutrition and physical education at Columbia University. “That’s incorrect. The amount of fat you’re going to lose is totally dependent on expending more calories than you take in.”
In other words, the problem is that as you decrease the intensity of your workout, you also decrease the overall number of calories you burn.
What matters most when it comes to exercise and weight loss is using as many calories as possible, so that at the end of the day, you’ve expended more than what you’ve consumed. According to Dr. Reznik Dolins, most people are likely to achieve this goal by exercising as strenuously as possible. (Hey, we don’t mind a few intervals.)
The bottom line? The idea that there’s some kind of magic zone whereby you exercise less intensely, don’t increase the length of your workout, and somehow burn more fat is, sadly, false. —Catherine Pearson
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This isn’t news. At least 10 years ago, I read critiques of the theory of the fat-burning zone, at least as applied to ordinary people, not athletes.
I discarded this theory about the same time I decided to ignore the heart rate zones. Whenever I exercised in the proper zone, I never broke a sweat — How could this be doing me any good? I asked the doctor about it and he said I wouldn’t kill myself with more exertion.
Bought a heart rate monitor to give me an idea of what’s normal for me and the rest is history (of on and off exercising).
It’s funny how in general most of the popularized theories tend to dumb things down. It’s always Do Less To Get More.
I agree with exerciser. This is not new. But the fact that you are revisiting it is excellent. I am a 67 y/o male, a former runner and triathlete, now unable to run. But I do work like hell on the bike and the elliptical as well as the rowing machine to get my hear-rate as high as possible. I work out between 40 and 70 minutes, normally 5 days/week. And, I really have kept my weight in balance.
By the way: I love the photo.
Thank you very much for this article. Every time I glance down at the machine I’m on (which is not often enough) I wonder why that information about fat burning zones is there. Even though I vaguely remembered hearing form my doctor years ago that calorie burning is what counts, it was good to hear from Dr. Dolins. Thanks again…
However, it’s also important to mention while exercising when the body is fueling on which energy resource. The first 30 minutes of exercise is usually fed by carbohydrates, from then on more and more fat is used up by the body for more energy. Reason why most trainers globally explain why cardio training need to last longer than 30 minutes to have an effect on the silhouette.