 This study will assess the sustainability of a two-year intervention and the degree of improvement in body mass index BMI and reduction in risk factors for type 2 diabetes and diabetes related cardiovascular disease, as well as evaluating the additive effect of metformin as GlumetzaTM 500 mg Extended Release Tablets and comparing an initial intensive exercise program with a standard exercise program. The study will recruit obese youth who are at risk for type 2 diabetes and cardiovascular disease. 