But the model-thin style is an unrealistic look for most people. Diets that don't allow any fat can also be bad for you. You should have a certain amount of fat in your diet, between 20 and 25 percent of your total calories. Don't fall for diets that restrict certain food groups, either. 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 in your usual way.
Some teens start dieting because they think all the problems in their lives are weight-related.
Once these teens start losing weight, they may get lots of praise and compliments from friends and family, which makes them feel good. But they will eventually reach a weight plateau, and they won't lose as much weight as before because their body is trying to maintain a healthy weight. They may also find they aren't any happier, but they still keep their main focus on their weight. Some teens may find it hard to control their eating, so they control it for a little while, but then eat tons of food. Feeling guilty about the binge, they use laxatives or vomit.