Its best to eat complex carbohydrates right before, drink lots of water during, and refuel with protein and veggies after. My daily sort of routine is wake up at 4:45 am, eat 1 or 2 pieces of whole grain toast with honey or preserves (you could eat it with peanut butter, but I'm allergic), a greek yogurt + some soymik for protein. I drink a LOT of water during my workout. Afterwards, I'll have a protein shake, some sort of soy protein, or make a juice with my juicer and some fruits. Keep drinking water afterward too, because your body is still heated up.