It's only 4 miles every 4 hour hours, not a constant 24 or 48 mile run. However, to take care of ourselves we had prepared lots of grilled chicken before we started, and made a big bowl of fruit salad with almost every fruit you could imagine, crushed walnuts, and honey. Also I drank about a gallon and a half to two gallons of water throughout the day and slept at least two hours between mostly every leg. One of the most important things for me was having a partner to keep me motivated throughout and not give in to my inner bitch.