Set up teens for success. Give them short-term, achievable nutrition and exercise goals.
Look for the hook that makes nutrition and exercise relevant to right now. Telling them it will make them healthy will not impress them.
Never put your child on a diet. Instead, learn to redirect behaviors. When your teen chooses a physical activity or a healthy food, pour on the praise.
Spend a half day each weekend devoted to family physical fitness outings. Be a good role model, but keep in mind that teens cannot compete with adults in sports and exercise.
Support physical education class requirements in the schools. Even if your child is not an athlete, encourage her to explore intramural sports, dance classes, martial arts or recreational swimming. Encouragement for teen girls is especially important because their activity levels decrease dramatically as their age increases.
Monitor your teen's after-school activities: 3 to 7 p.m. often is a time of high-risk behavior. Kids frequently come home, eat whatever they can find and then sit.
Be sure to provide plenty of positive feedback. In the end, your child may be chubby, but he doesn't have to be sick.