I think balance is a good idea. At a young age fruits are still sweet, so keep piles of that around. Do have a special treat they can have occasionaly though. For my son we get the splenda sweetened blue bunny icecream bars. On days he's not in school he can have one when he wakes up from nap. He is also allowed a free cookie when we go to the grocery store, and occasional jello.

With holidays such as halowwen and so on, he's not allowed to pig out, rather he can choose to have 1 piece of candy that day for his treat. He's happy because he gets the candy, I'm happy because he's not eating himself sick, and most ends up going stale and being tossed

Then of course he goes to his dad's and has lucky charms for dinner, bug juice, poptarts and so on, and don't get me started on school lunches. Realisticly you won't be able to cut sugar out of your child's life completely because there will always be school, friends houses, holidays, and the worst offender "relatives". Better to teach them moderation and make sure they have healthy alternatives as much as possible