Most people are under the impression that "natural sugar" is healthy for some reason, and think they gives them a free pass to gobble heaps of sugar in the form of grapes, oranges, bananas, apples, etc. Sugar is sugar, even when chained together to form a complex carbohydrate. Anything that causes insulin spikes is going to be detrimental, especially if people don't allow at least 12 hours a day where they don't eat.