Limit Screen Time
What's screen time? It's the amount of time you spend watching TV or DVDs, playing video games (console systems or handheld games), and using the computer. The more time you spend on these sitting-down activities, the less time available for active stuff, like basketball, bike riding, and swimming. Try to spend no more than 2 hours a day on screen time, not counting computer use related to school.
One job you have as a kid — and it's a fun one — is that you get to figure out which activities you like best. Not everyone loves baseball or soccer. Maybe your passion is karate, or kickball, or dancing. Ask your parents to help you do your favorite activities regularly. Find ways to be active every day. You might even write down a list of fun stuff to do, so you can refer to it when your mom or dad says it's time to stop watching TV or playing computer games!
Speaking of parents, they can be a big help if you want to be a fit kid. For instance, they can stock the house with healthy foods and plan physical activities for the family. Tell your parents about these five steps you want to take and maybe you can teach them a thing or two. If you're a fit kid, why shouldn't you have a fit mom and a fit dad?
Information taken from -http://kidshealth.org/kid/stay_healthy/body/fit_kid.html#