I recently read an article on how the arteries and heart problems of some obese children as young as 10 year old was similar to that of 40 to 50 year old people.
Basically it seems to be the fault of parents, that a lot of small children end up getting fat. Some parents do not seem to know the importance of proper diet and good exercise.
I guess the children of today spend more time watching tv, and playing video games or on the computer, than playing outside. Also some parents (single working moms due to divorces etc) do not seem to have enough time to cook healthy meals for their children and instead just buy fast food /prepacked/processed /cooked food /junk food high in fat and carbohydrate content from chain stores which need not always be healthy.
Some of the government subsidies for corn farmers lead to some components like high fructose corn syrup (HFC) showing up in many places in place of ordinary cane sugar.
Children are easily misled by marketing gimmicks into consuming carbonated sweetened drinks which are fattening.
In the old days children would walk or ride cycles to school. But nowadays parents are afraid of traffic and drive their children to school or send them via auto's or buses.
Overweight children are more likely to have problem as overweight adults.
Some of the problems like heart problems, diabetes (type 2 ?), breathing difficulties, high blood pressure , depression etc may be due to obesity.