in my opinion parents are the first who are responsible.Parents are the most close person of every child and they do got right to control the activities of their children.But nowadays due to their business or laziness,they feed different junk foods to their children which makes them obese.for eg they send biscuits and noodles to their children as a tiffin in school, they send their children to distribute chocolates during their birthdays etc..They have the key to shape their childrens life.so they are on the best position to change their childs problem....