What should I eat on my work breaks to keep my energy up?

Healthy snacks. It's important to consider any dietary restrictions you may have, but generally you want to eat snacks that are complex carbohydates, low calorie, low suger, low fat. Small portions are generally better than larger portions. You might consider eating a handful of nuts or some vegetables (carrot sticks, cauliflower, broccoli), a slice of whole wheat bread. It is better to graze - small amounts.
Work snacks. . You should have a small meal of complex carbohydrates and lean protein. Few hundred calories, just enough to get you to your next meal. Fiber will keep you from getting hungry. .