Genetic and endocrine disorders are rarely a cause of childhood obesity.
Parental obesity is a strong predictor of obesity later on in life for children. This may be due to genetic link, but also the eating behaviour patterns may be conserved in families.
Most cases of obesity are due to an imbalance of energy intake and exercise taken. The wide availability and targeted marketing of processed food contribute to the increased uptake of this food in children. Studies show that the actual calorific intake in children has not increased sufficiently over the years to account for the increase in body mass. It is likely that increasingly sedentary lifestyles and advancing entertainment technology are strong factors.