The shuar are known for drinking 0,5L pints of aya in their sessions. Avoid anything that will take you in a bad mood for several days (alcohol, coffein, any drugs) - you need to feel clean and reinforced and everything will be just fine.
In my opinion, no problem with any kind of food, but don't eat too lately the day before tomorrow. Avoid too much water. But after all - don't take these things too seriously, alles ist gut!
Arthur Dee was one of the greatest alchemists of all time, not likely to his dad, I forgot his name, this small James Bond sorcerer working for the queen of a... Hail Arthur!