If you can do the following, you're in good shape -- food-wise:
- Eat foods with plenty of fiber
- Eat whole, real, fresh, organic, unprocessed food
- Eat lots of fruits and vegetables with colorful phytonutrients
- And choose foods containing omega-3 fats.
The goal is nourishment. Foods that are heavily processed are more of a burden than a source of nourishment, creating work for your digestive tract. Foods that nourish are easier for you to digest.