i pack durable fruit (oranges, apples, banananas) and half a dozen hard boiled eggs for when i get to work, just make them the night before and grab them on your way out. i have a water heater (marketed for makin tea) at work; i'll cook up some oatmeal and mix in a gob of peanut butter when i get to work. oh, and i buy half a gallon of milk at the px on modays and leave it in our work fridge to drink all week. fills me up til lunchtime, easy, and doesn't take too much to prepare.