Just an anecdotal story – when I was a kid I was a sugar fiend. My parents didn’t know any better and went along with it. I would add a couple teaspoons to my raisin bran in the morning, eat Nestle Quik by the spoonful (skipping the milk entirely), get a ding dong in my lunch every day, build miniature towns out of the sticks from my fudgesicles, etc. One day as a teenager I decided to just stop eating it. I am now 40 and have no ill effects that I’m aware of, and am in fact in better physical shape than anyone I know. I guess I’m trying to say that kids who get too much aren’t necessarily doomed.
That said, we’re trying to keep it away from our kids as much as possible.