The best way to build your muscles is to use your muscles. Regular exercise not only burns calories, but increases muscle mass and tone. When you don't exercise, fat displaces muscle, muscles become smaller and weaker, and you gain weight more easily because even at rest, muscles burn more calories than fat. When you exercise, however, you help to reduce fat tissue while building muscle and bone. Muscle is heavier than fat but takes up half the space, so you can actually reduce your body measurements without losing weight.
Some teens have a difficult time projecting a healthy weight for themselves.
Girls especially may think they need to be thinner. If you're concerned about your weight, it's important to talk to a health professional such as your family doctor or the school nurse. That person can help you decide whether you do need to lose weight and, if so, the best way to achieve and maintain a weight that is healthy for you. If health professionals recommend that you need to lose weight, most experts say it's best to increase your exercise as the first step. Often that's all teens need to do for weight control because they're rapidly growing.