How to be sure if you are not too skinny or too fat?

If you think you've gained too much fat or are too skinny, a doctor should help you decide whether it is normal for you or whether you really have a weight problem. Your doctor has measured your height and weight over time and knows whether you are growing normally or not. If your doctor has a concern about your height, weight, or body mass index, he or she may ask questions about your health, physical activity and eating habits.

Your doctor may also ask about your family background to find out if you have inherited traits that might make you taller, shorter, or a late bloomer. That is a person who develops later than other people the same age. The doctor can then put all this information together to decide whether you might have a weight or growth problem.

If your doctor thinks your weight is not in a healthy range, you will probably get specific dietary and exercise recommendations. These recommendations will be based on your individual needs. Following a doctor’s or dietitian’s plan that is designed especially for you will work way better than following fad diets.

For teens, fad diets or starvation plans can actually slow down growth and sexual development, and the weight loss usually does not last. It is important not to make radical changes on your own, without your doctor's guidance, especially during puberty.

Most teens who weigh less than other teens their age are just fine, just they may be going through puberty on a different schedule than some of their peers, and their bodies may be growing and changing at a different rate. Most underweight teens catch up in weight as they finish puberty during their later teen years and there is rarely a need to try to gain weight.

In a few cases, teens can be underweight because of a health problem that needs treatment so if you feel tired or ill a lot, or if you have symptoms like a cough, stomachache, diarrhea, or other problems that have lasted for more than a week or 2, be sure to let your parents or your doctor know. Some teens are underweight because of eating disorders, like anorexia or bulimia, that require attention.