Food is extremely important to runners. Running taxes the body and you'll want to eat plenty of nutrient-packed calories to allow your body to have the best chance possible of adequately recovering. Many runners notice that the best runners in the sport tend to weigh very little and that leads many to eating disorders but this will not help your training. The best runners are skinny but they got there by eating a lot of nutriciuos food and gradually working up to running a lot.