I make my lunch the night before, usually a sandwich, a piece of fruit, maybe some nuts. Or, leftovers in a microwavable container. Put it in my lunch box (it's a soft-sided, insulated one I got from, I think, BB&B a few years ago) and put it in the fridge. In the morning, take it out of the fridge and put it in my pannier. At work, take it out of the pannier and put it in the cabinet in my office. It has been in the fridge overnight, and the lunch box is insulated, so it's fine at room temp. for a few hours until lunch time. I eat out infrequently, as a treat, usually when I've driven in for whatever reason.