Agree with stridercc. But I would up my intake to one every thirty minutes. That is what is recommended in the latest issue of "Bicycling" and I find that it works better for me if I know I am going to be hitting it hard for more than a couple of hours. Nice big oatmeal or spaghetti feed about an hour before the start and then plenty to eat every half-hour along the way. Got to keep the fire stoked.