If there is anything worse than being overweight it is being overweight, deciding to do something about it, trying to take it off, and failing.

It ought to be easier than it is. You diet. You exercise. It ought to work. But sometimes the weight doesn't come off. There is nothing more frustrating.

So what is the problem? Scientists from West Virginia University have given us an important clue. They studied the effect of exercise on body fat. (The effects of exercise intensity on body composition, weight loss, and dietary composition in women. J Am Coll Nutr. 1997 Feb;16(1):68-73.)

They had two groups of women. One group exercised with low intensity, and the other group exercised with high intensity. The researchers didn't try to change the diet in any way.

What they found was quite interesting. The high intensity group lost body fat. The other group did not, even though they exercised.

Not only that, but the high intensity exercise group lowered their intake of saturated fat and cholesterol. They did it on their own; there were not any recommendations made regarding diet. They ate what they wanted, but after high intensity exercise they had less of an appetite for fatty foods.

Now, the overall body weight didn't change, but they lost body fat. So what happened? They lost fat and replaced it with muscle.

The result of losing body fat and gaining muscle in women, and in men, is a better figure, a more attractive body. Your clothes fit better. You look better at the beach. You are more fit, so you are healthier and more attractive.

High intensity exercise is the key to getting fit, taking off fat, and developing a diet that you can stick with.

There is one other thing to keep in mind, however. High intensity exercise does not mean that you throw yourself into your exercise full force. For example, don't try sprinting or heavy weights unless you are a trained athlete. You won't be able to do it and you can hurt yourself. But just as importantly, it is not necessary.

You don't need to overdo it when you exercise. You just need to do a little more than you did last week. You just need to increase the intensity a little.

If you are out of shape, high intensity exercise for you may be a slow walk. That's fine. Start wherever you are and build up.

But it won't be a slow walk forever, and that is where most people fall down. If you are doing the same exercise you did last year, or even last month, you are cheating yourself. You will not see the fat loss you want, you will tend to be hungry a lot, and your weight will not likely budge.

High intensity exercise is the key. You will lose fat and automatically improve your diet without going hungry. And you will be on the road to having the body you always wanted.