role in the relationship between obesity and energy homeostasis. A deficiency of leptin causes severe hyperphagia and obesity, with physiological leptin replacement corrects both hyperphagia and obesity in leptin-deficient individuals. But most individuals with obesity have elevated plasma leptin levels, raising the possibility that common forms of obesity are associated with leptin resistance.

1. Lifestyle and diet:
Lack of physical activity is a major contributor to childhood obesity. Evolution of multimedia, television, internet, video-games are engaging the child in sedentary lifestyle. Parents are now more conscious about the academic performance of the child, as a result of which child’s physical activity is restricted.
According to NHANES III (1988-1994), the prevalence of childhood obesity is highest among children who watch television ≥4hours/day and lowest among those who watch ≤1hour/day.
A large randomized control trial by Robinson(5) compared two groups of children at similar public schools. One group received a 6-month classroom curriculum to reduce television, videotape, and video-game use, while the other group did not. Robinson found that compared to the control group, children in the intervention group had statistically significant decrease in BMI.

Aside from these lifestyle issues, eating patterns of children and adolescents have changed dramatically in the past few decades. The consumption of high calorie soft drinks and junk food has increased tremendously. Children who frequently eat fast food consume more total and saturated fat, more total carbohydrate and added sugars, less dietary fiber, less milk, and fewer fruits and vegetables than children who eat fast food infrequently.

2. Metabolic Programming:
It has been well established that the metabolic programming of an individual determines the risk of developing obesity. Evidence for this comes from studies in which adoptive children and identical twins brought up in different environments had a BMI similar to their biological parents/twin (6,7).
Other factors that contribute to the metabolic programming are: