I’d rather have cheese if I’m on a train and don’t need carbs for fuel. If I was riding a bike, I might feel differently.

If there’s a disparity in your bread/cheese supply, you could stretch it out by only eating one slice of bread at a time, folding it over a whole piece of cheese (also folded).

If I keep track of the quantities, I could definitely make the numbers match in the end. That’s probably a better approach than my “just wing it” style.