I’m guessing that food banks operating out of, say, churches dispense what they get from random donations. Canned veggies, tuna, Mac and cheese, rice, and other boxed carbs. Not much to choose from, and spotty at that.

A local Catholic Worker House we support obtains food for its meal programs from local grocery store discards mostly. They work at sourcing, and have excellent contacts. It takes special handling: large fridge and freezer storage for one thing, also achieved by scrounging. They do receive an astonishing supply of wonderful food, including fruits and vegetables, but it takes labor to store and process it without waste. They give away great quantities to the neighborhood (bread especially) and make creative plans for cooking: soups, casseroles, salads, etc. And they have chickens. Chickens eat everything!! The eggs taste good, too.