Exercise and Health Fitness

Staying Slim

Filed under: Essays — arlene @ 5:15 am

The old injunction to eat less and exercise more is good not just for overall fitness but for weight loss itself—but probably not in the way you imagine. For burning calories is not the only way exercise helps you lose weight and stay thin—probably not even the most important way.

Many women neglect exercise because of the mistaken idea that physical activity increases the appetite. This is not true. On the contrary, studies show that people don’t react to physical activity with a blossoming appetite. Regular exercise, unless it is excessively strenuous, will decrease your appetite. There appear to be several reasons for this:

1. You get hungry when your blood sugar level drops drastically. Regular exercise keeps blood sugar levels from fluctuating dramatically, because when muscles are regularly exercised the amount of fat they oxidize is increased and the amount of carbohydrate burned is reduced. Since your muscles are using more fat, they don’t take as much sugar from the bloodstream.
2. When you exercise, peristaltic movement in the intestines increases. The transit time for foods to pass through the body and wastes to be excreted is diminished. As a result, your body actually absorbs fewer calories.
3. Exercise also raises your metabolic rate so that your cells burn oxygen more efficiently, make better use of nutrients from your diet, and more thoroughly eliminate waste products. This also probably contributes to the appetite-decreasing ability of exercise—because you are getting better nourishment value from your foods, you are inclined to eat less.
4. When you exercise, your temperature is raised. The elevation of body temperature brought about by physical activity also helps inhibit the feelings of hunger. Fat mobilized in the process supplies enough energy to inhibit the desire for food for up to forty-eight hours after strenuous physical activity, probably because your body is producing enough blood lactate to affect the metabolism of glucose in the satiety center. And this beneficial exercise-caused elevation of temperature, or “thermogenesis,” is not short-lived either. Your resting basal metabolic rate remains raised by as much as 10 percent for up to forty-eight hours after strenuous activity.

Exercise can also make you lose inches because it helps turn fat into energy while at the same time building muscle. Muscle tissue weighs more than fat which is why, when you begin to exercise, you find you are losing inches more rapidly than pounds. In fact, to lose weight successfully and keep it off you have to exercise. Researchers have shown that about a quarter of the weight lost by restricting calories alone is lost in muscle tissue. If you go on a slenderizing regimen without exercising, you will lose this muscle tissue and then later, if you regain any of the weight lost, you will regain it in fat, not in muscle. This means you will be even more flabby than you were to begin with.

And just in case you have fears of exercising because you think you will develop big bulky muscles, forget it. This won’t happen with any kind of rhythmic exercise such as running, swimming, bicycling, or dancing. These activities tend to form long muscles and beautiful bodies. Only resistance exercises, such as certain kinds of weight lifting, will bring that kind of bulk, and even that is unlikely for a woman as big muscles occur only in the presence of sufficient male hormones, and most women have far too few in their bodies to make it possible.