There is a long-held belief that exercise can turn you into a fat-burning machine. The idea is based on the suggestion that fat burning occurs not just during exercise but also long after your workout is over. Post-exercise burn, so the theory goes, is instrumental in losing unwanted weight.
As it turns out, however, like so many headlines touting weight-loss miracles, this one is probably more myth than fact according to an article titled ‘Exercise improves fat metabolism in muscle but does not increase 24-hour fat oxidation’ that appeared recently in Exercise and Sport Sciences Review
Edward Melanson, an exercise physiologist from the University of Colorado and lead author of the article said “To our surprise, we have found that moderate duration exercise has little, if any, effect on 24-hour fat oxidation (burning).”
Melanson used an interesting design to challenge the long-held belief that exercise enhances fat burning. Sixty-five candidates of varying fitness level and girth (well trained and sedentary, lean and obese) all cycled at varied intensities until they burned 400 calories, after which they were monitored for 24 hours – a period that exceeds most other studies by several hours. All were monitored in closed quarters and were able to eat during the 24-hour period. None posted results that suggested enhanced fat burning during or after their workouts.
The study has caused quite a stir among fitness experts who now have to think twice before suggesting that exercise boosts metabolism in the short or long term.
Before people begin putting their feet up in protest, keep in mind that this study in no way diminishes the value of regular exercise. Working up a sweat is still one of the best things people can do for their health. Regardless of the amount of fat that may or may not be burned post-workout, there’s no denying that a moving body burns more calories per minute than a sedentary one.
The message about fat burning has always been confusing for the average exerciser wanting to get rid of a little extra baggage. The often-touted premise that certain forms of exercise or that working out at a certain intensity can selectively burn off unwanted fat stores is without scientific merit.
In fact, the fixation on fat burning is misguided. When it comes to achieving weight loss goals, any calorie burned is a good one – whether it be in the form of fat, carbohydrate or protein. As long as we burn more calories than we consume, the weight will come off.
According to Pascal Imbreault, associate professor at Ottawa University’s School of Human Kinetics, any exercise-related after-burn usually runs its course within 15 to 35 minutes of completing a workout. While the actual number of calories expended during this time varies according to exercise intensity, duration and the body weight of the exerciser, he describes the resulting calorie burn to be “very minimal.”
Imbreault suggests that exercise doesn’t do much to crank up metabolism over the long term either, despite what the headlines in fitness magazines claim. “Exercise is not that powerful,” he said.
By making healthy food choices and cutting portion size to reduce the number of calories consumed on more days than not, anyone can become a calorie-burning machine that slowly but steadily loses excess body weight.
Source: The Montreal Gazette