While the debate over childhood obesity rumbles on and experts search for reasons for the epidemic, a clutch of new studies recently published suggests the causes are a combination of factors.
Foremost though appears to be the immediate environment children find themselves in.
Much of the blame is attributed to media advertising where children are bombarded at school and at home by adverts for drinks, junk food and fast food..... where often rewards are offered in the form of toys or games.
The decline too of many sports and physical activities in schools also plays a significant part in the childhood obesity epidemic as does the rise in sedentary activities such as computer games.
Experts suggest the combination of such factors may explain why childhood obesity has reached such proportions and they say environmental factors and policies are challenging the health of children in America.
A number of new studies by researchers at the University of Illinois-Chicago and the University of Michigan examined teenagers' surroundings, and their findings confirm earlier research.
Their conclusions appear in a special supplement of the American Journal of Preventive Medicine and say schools and communities will continue to encourage the childhood obesity epidemic until policies are adopted to improve the health of children and communities.
They believe policy changes could make healthy choices easier.
Lisa Powell of the University of Illinois, Chicago, examined restaurant and food store options in neighborhoods and food-related television advertising aimed at teens.
She says lower-income neighborhoods tend to have a higher proportion of fast-food restaurants, and black urban neighborhoods have the highest percentage of fast-food restaurants.
Powell says when people rely on convenience stores that seem to proliferate in many poor neighborhoods, families eat less healthy food.