> The lack of a counter system for sweets suggests that it
  > wasn't abundant, at least not to the degree that we could 
  > eat enough of it to prevent us from reproducing.

There is a counter system to eating foods that are sweet, provided foods are eaten in their whole, fresh, and ripe state.

Try to overeat on fruit - it's imposssible. You'll feel full and be tired of "sweet" long before you could ever overeat on it. Fiber and sufficient blood sugar have a way of telling one when they have been satiated.