It's all about teaching them choices and how that affects what they may or may have later. With my stepkids, I try to strike a balance between the amount of fruit or veggies they have vs. the sugar. They have always been allowed to eat whatever they want by their mother and now the older one has to be on a diet because she is obese for her age. She is on a modified Atkins, but I still try to maintain the balance - no Atkins icecream unless you've had your veggies for the day. If they have a soda at lunch, then they can't have one with dinner. It seems to work out, and I haven't seen them binge when we go to parties or heard complaints from friend's parents.