Despite the fact that your brain only accounts for 2% of your body weight, it consumes up to 20% of your daily calorie requirement. If you want your brain to function like a finely-tuned engine, you have to keep it well fed. But what exactly does your brain eat? The brain is a picky eater, but there are foods that help it to function well. This information is of great import if you want to knock it out of the park when you are writing an exam, attending an important class or meeting or giving a presentation.