One of my favorite fitness “facts” has just been foiled by a new study. Exercise has long been thought to have the secret weapon of stoking your metabolism 24 hours a day. Not so fast, say experts.
Edward Melanson, an exercise physiologist and associate professor of medicine at the University of Colorado in Denver, says that this has led people to believe that diet doesn’t matter so much, as long as you sweat it out at the gym.
“People think they have a license to eat whatever they want, and our research shows that is definitely not the case,” he says. “You can easily undo what you set out to do.”
Melanson says other experts in his field have been “flabbergasted” by the results.
“Bottom line is that we once thought that exercise would burn calories, especially fat calories, for a long period after a bout of exercise,” says exercise physiologist Gerald Endress, fitness director for the Duke University Diet and Fitness Center who was not involved in the research. “This does not seem to be the case.”
Another overblown fitness factoid is that you burn more fat when you build muscle. While it is true that muscle burns more calories than fat, the difference is fairly negligible. Muscle burns about 7-10 calories a day while fat burns two calories. Most people don’t put on enough muscle to make a significant difference.
The first question that comes to my mind is, what were the studies that brought experts to the earlier conclusions about the 24-hour metabolic benefits of exercise? This new study only followed 65 exercisers. Is that all it takes to topple a long-held scientific belief?
This isn’t meant to encourage people to not re-up their gym memberships. Nothing could be further from truth.
“It’s not that exercise doesn’t help with weight loss,” says Melanson. “It’s that it’s harder to lose weight with exercise than diet.”
While this may seem frustrating and confusing, in actuality it brings home the point that the main thing to focus on is simple math. You take the number of calories in minus calories out. If you have a deficit, you will lose weight.
To lose a pound of fat, you need to create a deficit of about 3,500 calories. To lose a pound a week you can reduce your eating by 500 calories a day or burn an extra 500 calories each day through exercise.
June 7th, 2009