Tuesday, November 10, 2009

Working out weight loss

















The one thing people easily forget about weight loss is that you can work out for 30 minutes and gain all the calories back with one Gatorade or protein bar. In other words, if weight loss is the goal, focus on calorie intake, not the treadmill, as this piece in The New York Times reminds us.
"For some time, researchers have been finding that people who exercise don’t necessarily lose weight. A study published online in September in The British Journal of Sports Medicine was the latest to report apparently disappointing slimming results. In the study, 58 obese people completed 12 weeks of supervised aerobic training without changing their diets. The group lost an average of a little more than seven pounds, and many lost barely half that.
How can that be? Exercise, it seems, should make you thin. Activity burns calories. No one doubts that.
“Walking, even at a very easy pace, you’ll probably burn three or four calories a minute,” beyond what you would use quietly sitting in a chair, said Dan Carey, Ph.D., an assistant professor of exercise physiology at the University of St. Thomas in Minnesota, who studies exercise and metabolism.
But few people, an overwhelming body of research shows, achieve significant weight loss with exercise alone, not without changing their eating habits.
“Many people believe that you rev up” your metabolism after an exercise session “so that you burn additional body fat throughout the day,” said Edward Melanson, Ph.D., an associate professor in the division of endocrinology at the School of Medicine and the lead author of the study. If afterburn were found to exist, it would suggest that even if you replaced the calories you used during an exercise session, you should lose weight, without gaining weight — the proverbial free lunch.
To their surprise, the researchers found that none of the groups, including the athletes, experienced “afterburn.” They did not use additional body fat on the day when they exercised. In fact, most of the subjects burned slightly less fat over the 24-hour study period when they exercised than when they did not."

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