Our primary outcome measurement is body mass index (BMI) as this is now recommended by major health organizations as the preferred measure for the determination of obesity. All children at YMCA After School Programs will receive either YMCA-PAN or YMCA standard care; however, we will only follow children in grades kindergarten through second grade (K-2). For children in grades K-2, we will determine if 3 years of increased physical activity and snacks lower in energy and fat and higher in nutrient density will diminish gains in BMI. We have specifically targeted an increase of moderate to vigorous physical activity (MVPA) by 225 minutes per week that is delivered in YMCA-PAN as this is a compromise between the recommendations suggested by Healthy People 2010 and the Institute of Medicine (IOM) and is administratively feasible within the existing YMCA After School Programs. YMCA-PAN would exceed the Healthy People 2010 guidelines and would provide the majority of PA for the IOM guidelines. Children would satisfy the IOM guidelines with just 15 additional minutes of MVPA accrued throughout the day in physical education class or free play. Finally, YMCA PAN would provide opportunity for PA at the very time the guidelines call "most critical:" the hours between 3 and 6pm when children have finished the school day and frequently are sedentary. For the nutritional component, we are targeting snacks, as snacks are part of the YMCA after school programs, snacks contribute significantly to 24 hour energy intake, children are increasingly in control of the snacks they consume, and we have previously diminished 24 hour energy intake and fat intake using snacks in elementary school children.