On Sundays I do lunch prep for the days in office. A few slices of deli meat and block cheese for a nice flavor. Then a pile of raw veggies and a small container of dipping sauce. I prefer sliced bell pepper and green onion with ranch dressing, but you can do whatever veggies you prefer (for example spinach, sugar snap peas, carrots). I always feel great after that lunch; grains like bread or chips always made me feel lethargic.
I take it into the office in a plastic bento box to keep everything from jostling around, and the sauce goes in a smaller reusable container separately.
stop doing math