Best thing to do is try it out for a month or 2 and see how you feel. You are young and your metabolism can probably handle the daily candy bar if that is your only "flaw" in your diet. Most people though don't realize all the things that have hidden sugar like soda, ketchup, gatorade, etc.
Eating good, whole foods like fresh vegetables and fruits are better for your body then candy but heck, when I was 17.... I could eat a whole large pizza all by myself and not worry about it.
