Exercise, Weight Loss, and Metabolism

Here is a fascinating exchange from the New York Times’ head science writer, Gina Kolata about her book, RETHINKING THIN. Here is the book excerpt in question.

This excerpt makes that case that changing the body’s weight above (resp. below) some intrinsic value causes the body to increase (resp. decrease) its metabolism. The research seems good on this.

This doesn’t mean that people are powerless to reach their desired weight. There seem to be effective ways to increase a body’s metabolism beyond adjusting caloric intake. It seems like increasing muscle mass, doing aerobic exercise, drinking caffeine, and eating small amounts throughout the day all can increase your metabolism. Are any of these things known to be effective in counteracting the body’s use of metabolic rate to maintain some given weight?
— Posted by A. Johnson

2.
May 7th,
2007
11:49 pm
The real issue is, how realistic is the desired weight? In studies, many obese people state a dream weight but almost no one achieves it and of those who do, almost no one maintains it. It can be very difficult to become as thin as you might want to be and stay that thin. On the other hand, many people can successfully lose modest amounts of weight and keep those pounds off. But you asked about other methods to increase the metabolism. Exercise can increase the number of calories you need but it does not increase your metabolism. And the amount of calories most people burn, particularly with moderate exercise, is not very significant, 100 or 200 calories per session. Increasing muscle mass does nothing for metabolism – that’s an exercise myth. The reason is that any added muscle is minuscule compared with the total amount of skeletal muscle in the body and muscle has a very low metabolic rate when it is at rest, which is most of the time. A man who weighs 70 kilograms, or 154 pounds, for example, has about 28 kilograms of muscle. His muscles, when he is at rest, burn 22 percent of his body’s calories — the brain uses the same amount and so does the liver. If the man lifts weights and gains 2 kilograms, or 4.4 pounds of muscles, his metabolic rate would increase by 24 calories a day. The average amount of muscle that men gain after a serious 12-week course of weight lifting is 2 kilograms.

— Posted by Gina Kolata

One more in a series on why you can’t (or don’t) lose weight and keep it off or what the diet and excercise industry doesn’t want you to know. This stuff really ticks me off.