When you begin a run, you should feel neither starved nor stuffed. You don't want to eat immediately before running because it may lead to cramping. Running on an empty stomach may cause you to run out of energy. You best bet is to eat a light snack or meal about 1 1/2 to 2 hours before you start running.

Choose something high in carbohydrates and lower in fat, fiber, and protein. Some examples of good pre-workout fuel include: a bagel with peanut butter; a banana and an energy bar; or a bowl of cold cereal with a cup of milk. Stay away from rich, very fatty, or high-fiber foods, as they may cause gastrointestinal distress.

I cheated on this answer, I need the points : http://running.about.com/od/nutritionandhydration/f/preruneating.htm