Exercise not effective in weight control
An interesting report from
Tech Central Station regarding the efficacy of exercise for weight control. Hat tip to
Kim DuToit.
bq. To combat the obesity epidemic our government wants us to get into shape. Former U.S. Surgeon General C. Everett Koop's Shape Up America! has been updated with Shape Up & Drop 10™ and Surgeon General David Satcher's 10,000 Steps Program. A multitude of other compulsory exercise programs targeting fat have also been instituted by major employers, schools and healthcare providers.
bq. The shared goal of these exercise initiatives is weight loss. The underlying belief is that being "in shape" means being thin and no one would be fat if everyone exercised. For consumers, the take home message is that the whole point of exercise is to be thin. In fact, we're admonished everyday to exercise to lose weight.
bq. Trouble is, exercise - as necessary as it is for us -- won't make us thin.
bq. "I think fitness and medical professionals are doing a disservice to their clients when they position exercise as a way to lose weight," said Jennifer Portnick, personal trainer and certified aerobic exercise instructor at Feeling Good Fitness in the Bay area. "Becoming active may or may not result in a change in weight."
bq. But few of us realize that the most significant body of research shows exercise doesn't appreciably change body weights at all.
and more:
bq. Recognizing that many of the studies finding beneficial weight loss due to exercise were not well controlled, researchers at the University of Texas conducted the
Heritage Family Study. Led by Jack H. Wilmore, Ph.D., they put over 500 men and women on a 20-week endurance training program. While concluding that exercise can induce favorable changes, the study admitted they're of "limited biological significance." Yet the researchers speculated that increasing the intensity and duration of exercise would "likely have a major effect on body-composition and fat distribution." (As we'll see, that hopeful prediction didn't prove out.)
bq. Just how "limited" were the weight loss benefits of exercise? Men lost 0.4 kg and women a mere 0.1 kg! Other research, such as the
meta-analysis done by researchers at the University of Vermont, has consistently found women lose less fat and weight than men, an understandably important biological attribute for preserving fertility and the survival of the species. "In a recent study conducted in our laboratory," wrote Wilmore, "previously sedentary, moderately overweight women placed on an intense, 6-month, resistance-training program actually gained total mass and fat mass, even though they were instructed to maintain the same diet and activity pattern that they had before starting the study."
bq. Yes, many studies have found women actually gain weight and body fat with exercise. In another
study in which obese women did 6 months of aerobic exercise 4 to 5 times a week, one-third of them gained as much as 15 pounds of body fat, with the average of the gainers being 8 pounds. That's body FAT, not weight, emphasized Glenn Gaesser, Ph.D., associate professor of exercise physiology at the University of Virginia, a Fellow of the American College of Sports Medicine and author of Big Fat Lies: The Truth About Your Weight and Your Health (Gurze Books, 2002). "Just to make it clear that the weight gain was not muscle, as fitness buffs might assert. Thus a true skeptic might ask whether "exercise" has contributed to the obesity epidemic!!"
What works is based on basic thermodynamics - you will burn 1,800 to 2,400 calories per day. Eat less.
Exercise is great for other things - this is not saying that we should cut exercise from our lives
but, we should not expect it to contribute to weight loss - the only thing that can do that is a dietary modification.
Posted by DaveH at January 9, 2004 12:26 PM