Obesity is the condition of having an excessive accumulation of fat in the body, resulting in a body weight more than 20% above the average. Extreme obesity is now found to be more prevalent among children aged 10 to 17. Children are at risk for obesity now more than ever as they increasingly spent more time on homework, TV and Internet, without getting any physical activity. Meanwhile, they are having fast food products more than that of their body need. Therefore, an obese child can actually be undernourished due to the lack of vitamins and nutrients in the foods he consumes. Obesity not only increases the child's risk of numerous health problems such as heart disease, joint problem, and stroke, but also creates emotional and social problems. Teens with weight problem can experience teasing and isolation by their peers, leading to social withdrawal or even autism while society too often stereotypes the overweight as awkward, ugly, or spoiled. These undoubtedly affect a teenagers self-esteem and personality development, and even lead them become depression, anxiety and obsessive compulsive disorder that further decreases their interest in normal activities and may thus decrease their level of physical exertion.