It All starts with Sodas, but I am not sure where it goes from there.
I have just returned from our community swim meet. Kids drink multiple sodas and get heavy and swim slow.
Kids drink water with the occasional small portion of soda stay lean and swim fast.
My wife and I have observed this for the past 12 years at our community pool with ~400 members. Slim kids drink water mostly, heavy kids always have a Coke in hand. 24, 32, 48 oz behemoths.
Years ago when I went to school there were the couple of Fat Kids. Now MOST Kids are Fat. And they are always drinking Sodas.