How does sugar impact our brain? Well, this is a tale of two sugars - glucose and fructose. Both occur naturally, but one of them has a vastly different way of communicating with your brain. In one corner we have glucose, commonly found in pineapples and oranges among others. The consumption of this sugar registers a “full” feeling in the brain. So basically you eat enough of the foods with this in it and your brain thinks “Oh boy, I’m stuffed.” Now, in the other corner you have fructose, commonly found in sodas and canned foods.