What they said.

I'd add that protein will often keep you filled up longer, so something like a hard boiled egg (or just the whites), some turkey slices (if you can keep them cool). Like Susan, I take a large bag of food to work the beginning of each week. I have access to a fridge and a microwave, but seldom to a full lunch hour!

It helps to have things that you can grab and eat in a few minutes. Planning is the key.