I eat dinner before I go to work, sometimes it's soup and a sandwich, chicken nuggets, or breakfast. It's rarely a meal that takes any length of time to fix. As long as my DH is fed, he's happy! I only have a couple of hours before I have to start work. I usually take a banana or other fruit, yogurt, sometimes a small frozen bagel that will be thawed by the time I'm ready to eat it. Leftovers are good! I also keep a frozen dinner in the freezer at work. I keep a can of soup that will microwave in my bag. It's good to have quick snacks available so you don't go to the vending machines too often!
We do have a cafeteria open for a couple of hours at midnight, but the food varies, so I like to have a back-up plan. We sometimes do a potluck, and have more than enough food for the ones who didn't know that we were having one! Some nights we have pizza delivered, or get food from a local restaurant.
You do need liquids, and water, energy drinks, sodas and coffee or tea are popular. I hate to buy drinks from the vending machines, I don't like the $1.50 or $2 prices. It's easier to take everything with me, so on crazy nights I can keep going.
Then I go home and eat breakfast before I go to bed.