Obesity is a major public health concern. Obesity predisposes to insulin resistance and type 2 diabetes, hypertension, and heart disease. Childhood obesity is most prevalent in developed countries. Obesity in children and adolescents may lead to long-term complications. Obesity is usually caused by a combination of overeating and sedentary lifestyle. Obesity charts can help clinicians assess obesity. Treatment for obesity includes dietary modification, exercise, medications, counseling, and obesity surgery.