DOES THIS SOUND LIKE A GOOD INTRODUCTION FOR A CHILD OBESITY ESSAY? AND ALSO WHAT ABOUT MY THESIS.. HELP PLSSS?

The subject of childhood obesity is a good one. However, your presentation needs work. For example "Numerous children are victims of variety of health problems inflicted by the insufficiency of good nutrition and physical activity" then later "Not only do they have an inadequate nutritious diet, they also are lacking physical activity in their lives..." You are repeating yourself unnecessarily.