Boosting metabolism speeds pound loss.

You are trying to lose weight, but just can't pass up that mid-afternoon candy bar snack. As hard as you try to keep your dieting willpower up, your mind seems to be fighting it on both an emotional and psychological level.

While many people used to think that unsuccessful dieting was all in their heads. research from the Laboratory of Human Behavior and Metabolism, Rockefeller University, demonstrates that bodies fight dieting physically as well. Just as you begin to lose weight, nature takes over, making it even harder to keep unwanted pounds off. When people lose weight through calorie restriction, their metabolism - the rate at which they burn calories - actually slows down.

At the start of the study, the men and women who were put on a diet burned about 3,100 calories a day. After they had lost 10% of their body weight, however, they burned 15% fewer calories (about 2,500 calories per day) than other obese people who had not slimmed down.

"The results of this study indicate that the human body has a sort of natural 'survival mechanism' which fights dieting," explains Jeff Zwiefel, an exercise physiologist and director of the National Exercise for Life Institute (NEFLI). "Unless dieters take steps to keep their metabolism working at a high level, it will naturally slow - and stay slowed - as they lose weight. This means that keeping weight off becomes extremely difficult. Even if people continue eating less, they'll still slowly regain the lost weight."

According to Kenneth Cooper, founder of the Cooper Institute for...