My understanding is that it's not about total amount of sugar, but rather the glycemic index of consuming something. The whole apple contains fiber which would

My understanding is that it's not about total amount of sugar, but rather the glycemic index of consuming something. The whole apple contains fiber which would give it a lower glycemic index than a soda. The glycemic index of foods affects your insulin response, which affects fat storage behavior of your cells. I don't have a link to paste at the moment, but look into books by Gary Taubes for research and sources on this topic.