From a runner’s diet website:
Endurance athletes in particular benefit from fuel-efficient complex carbohydrates because of the extra calories burned each day. You need to aim for even more total carbohydrates than the suggested 50 percent. You can eat (in fact, may need to eat) more total calories without worrying about weight gain. The average runner training for a half marathon and running 20 to 25 miles a week probably needs a daily caloric intake near 2,500 to maintain muscle glycogen stores. As your mileage climbs beyond that, you need to eat more and more food, not less. In all honesty, this is why a lot of runners run, and why they train for marathons. Their common motto is, “I love to eat.”
So much for all those “long-form” blog entries I promised. There will be more.