You could drink liquid lunches of juice or milk, or even meal supplements such as instant breakfast drinks, GatorPro, or Ensure. I'm on a diet. Skipping lunch is a common mistake among weight-conscious people who believe eating lunch adds needless calories to their diet. They'd be better off eating a substantial breakfast and lunch and restricting calories at night. I don't like the cafeteria's lunches, but I'm too rushed to make lunch in the morning.
Any fuel is better than no fuel.
If the available lunches are high in fat, compensate by eating less fat at other meals. Go elsewhere to eat. Keep a variety of lunch foods stocked in your desk drawer. You can pull together a reasonable meal from dried soups, crackers, peanut butter, dried fruits, instant oatmeal, energy bars, and other nonperishable items. Make time to pack a lunch.