The prevalence of childhood obesity and its comorbidities is high in Japan. Increasing prevalence of obesity among children emphasizes the importance of focusing on primary prevention to avoid health complications later in life. We emphasize the prevention of obesity by recommending breast-feeding of infants for at least 6 months and advocating that schools provide for 60 min of moderate to vigorous daily exercise in all grades. Treatment interventions include behavioral therapy, reduction in sedentary behavior, and dietary and exercise education. After dietary treatment combined with exercise treatment, the areas of subcutaneous and visceral fat decreased significantly. These data suggest that dietary treatment combined with exercise treatment in obese children normalizes the distribution of abdominal fat and reduces the risk factors for chronic disease.