You know the effect calories ( 卡路里 ) have on your body. For each pound of weight that your body carries, it takes about 12 calories to keep it alive. If you weigh 150 pounds, you need about 1,800 calories per day to keep yourself alive. It is bad that if you eat more. If you eat more than 1,800 calories per day, the extra ones turn into fat. Let ’ s say that you eat 2,000 calories per day. That extra 200 calories are going to turn into fat. Then you go on a diet ( 减肥 ) and you eat only 1,000 calories per day over the long run.The diet really takes the weight off. But the weight comes right back when you return to your “ normal ” eating pattern. The lighter you are, the fewer calories you need. There are only two ways to keep the weight off: Change your overall ( 全面的 )eating pattern,or start exercising so that you “ burn ” the extra calories you take in.The best course of action is to put these two ways together.