Eat healthy&exercise. I generally avoid having parents focus on having their child lose weight at this age (unless significantly obese). It's best to avoid weight gain (as your child is still growing, s/he can get more "lean" by just not gaining weight)! best to eat right & fill the plate half-full with fruits/veggies. Limit carbs (rice, bread, pasta, juice, chips). Get plenty of exercise- sports are great at this age!