for 4 am in the morning....its a lot earlier than ive ever done (6 am),but what I used to do was carboload the night before with either pasta or rice then have a carb drink whilst getting my kit on, this seems to be fine as id usually done the same.i.e intense work and didnt like the idea of bringing my food back up.

...and if im out for more than 2hours take some carb drink with me.