Any diet on which you eat fewer calories than you need to get through the day — like an 800-calorie-per-day diet can be dangerous. Diets that don't allow any fat also can be bad for you. Everyone needs a certain amount of fat in their diet — up to 30% of total calories — so no one should eat a completely fat-free diet.
Don't have diets that restrict （限制）certain food groups, either. A diet that requires you to say no to bread or pasta or allows you to eat only fruit is unhealthy. You won't get the vitamins and minerals you need. And although you may lose weight, you'll probably gain it back as soon as you start eating normally again.
Some people start dieting because they think all the problems in their lives are because of weight. Others
