1st Rule – DON’T EXPERIMENT ON RACE DAY!
That means if you haven’t tried it before on a long run, don’t try it on race day. If you haven’t practiced anything, well, then, uh, I guess you’re going to have to do something and be conservative, but if you’ve been ok without anything, you probably ought to race that way. That said, I definately feed my body before, during, and after a race.