I recently read that adding cinnamon to sugar lessens the body's insulin reaction to it. I add cinnamon to my oatmeal. I added cinnamon to my apple slices and find that I like enjoys apples more this way.
I decided to check out if this is true and found a few articles about the benefits of cinnamon. This article from The World's Healthiest Foods even mentioned the sugar and insulin effect.
Of course it mentions not to overdo it as too much cinnamon can be toxic. But I doubt that it a problem with a apple a day.