Dr. Rachel Tells you how to Eat.

For speedier afternoon thinking, which snack should you choose -- a ripe banana or a chunk of cheddar cheese?

Go for the banana. Why? High-carb/low-fat foods test better than low-carb/high-fat diets when it comes to giving you a mental edge.

Combo Effect
Both low-carb/high-fat and high-carb/low-fat diets appear to perk up people’s moods, but when it comes to things like brain processing speeds, high-carb/low-fat foods beat others to the punch. Makes sense. Carbs are a critical source of the type of energy that brains need to perform. Fat, on the other hand (especially saturated fat), seems to bog down the mind.