As far as I have been able to find out it takes over 2,600 calories to gain 7,815' of altitude over the 13.32 miles. I start with a good breakfast an hour and a half before the start then an energy bar and endurance drink 30 min. before the Ascent then I take a hammer gel pack and two cups of water at EVERY water stop starting at the first (take a few tums with you). A Search and rescue member told me a few years ago that gatorade will dehydrate you at altitude, I can confirm that. You are on the right track asking this question to preventing yourself from being a zombie but you will probably see some above tree line. All you can do for them is tell them to keep moving.
