I like what Koni said about a new system on the kingdom islands.
Hunger definetly shouldn't be removed while on them that way you can't starve the enemy into defeat.
The only place the hunger, damage etc should be disabled is the games island.
In Unix thread it sounds as though castles will have a vault so they can keep food in there and something like a wagon could be made out of boards that can hold large amounts of food for when you are going to invade.