This is a just an observation with 100% junk science. When I was in elementary school in the late 1970s we drank and would eat anything and no one was fat. We would run like horses playing whatever sport was in season before school then we had milk break, drank our milk fast as we could then would run some more. Then eat lunch as fast as we can so we could play a one more again. Then again we would go crazy during recess before the school buses arrived. If you were fat you were rare. The vending machines had all the sugar and caffeine soft drinks and no one ever whined about it. This was before video and computer games and general lack of physical movement. Today you see overweight children all over the place with their attention focused on the latest I-phone or whatever. I believe the problem is just a simple lack of movement and physical exertion.