If I had to go on a strict, strict budget, I think I could live on beans and tortillas (of course, I would want salsa and cheese on them). For example, I had a bean salad for lunch and these beans for dinner. I made them last night, so when I came home from getting a manicure, I did not have to do much. I did make my tuna for the next days lunch.
I got on the scale, and sure enough I did gain TWO pounds. Doesn't sound like a lot until you realize that means I ate 7,000 calories that I didn't burn off!