That's funny you mentioned ultrarunners as one of the guys I'm going up with is one. But we've never had a discussion about 'loading' before a race. He's run up/down the Whitney trail in the past & he's already talking about doing it twice next week. Not the same day but subsequent days. We will be camping on the trail. I suppose if I'm feeling good enough I might try it a second time also....
-cat
Google 'Dean Karnazes Pizza' for example or read this
Wired.com article . On the other hand, you have a guy like Scott Jurek who's fully vegan.
Whatever works for you.