Which would be the best natural and healthy foods for energy?

What do you mean: ...By natural? The best diet is to eat foods that your great grandmonther would recognize. Fresh produce, whole grains, meats in moderation. Here is a good trick. Try to eat something of every color once a day, and no i don't mean m&ms. Eat things that are naturally colorful (berries, veggies, beans, whole grains). "energy" comes from carbohydrates and fat. The less processed the better.

Complex carbs.: For sustained energy through the morning, focus on complex carbohydrates and fiber. Foods like high fiber breakfast cereals, multi grain bread for toast and berries,will keep you going. A B complex vitamin will help your body use the carbohydrates efficiently.