Great article on Active.com describing the diets of elite Kenyan distance runners.
About 86 percent of daily calories came from vegetable sources, with 14 percent from animal foods. As you might expect, the Kenyan-runners’ diets were extremely rich in carbohydrate, with 76.5 percent of daily calories coming from carbs. The Kenyans ate about 10.4 grams of carbohydrate per kilogram of body mass each day, or approximately 4.7 grams per pound of body weight.
An amazing facet of the Kenyans’ eating habits was the consistency of this carbohydrate intake: Every 24 hours, the Kenyans took in about 600 grams of carbohydrate, with very little variation from day to day. They were truly stocking their leg muscles with glycogen, giving their sinews the right fuel necessary for the high-intensity training they were conducting — and avoiding the fatigue which automatically follows on the heels of glycogen wipe-outs.