If you feed kids high-calorie junk food they will get fat. Then they will get diabetes.

Kids don't need to eat 2,000 calories a day.  If they eat that much (like a happy meal, a bag of doritos, a snickers, a big gulp and some ice cream) they will gain in excess of a pound a week.  Unless that kid is growing at an astronomical weight or is running around like a Tasmanian devil, s/he is going to be overweight.