When we were young and in the military, leftovers were put in “glop pots”. The veggies went in one freezer pot, beef, pork/chicken went into their pot and sauces into another. About every 2 or so weeks, the veggie pot, sauce pot and either beef or pork/chicken pots were raided and made into either a stew or casserole. I’d bake a couple loaves of bread, put together a salad and we’d invite friends or bachelors over for a feast. We learned how to cook eggs many different ways. Leftover seafood ended up in sandwiches or became fish patties. Nothing went to waste.
That’s what my mama taught me, and we have never gone hungry. I believe it is sinful to throw away massive amounts of food, and not use leftovers...we Americans are so blessed and we have no idea what real hunger is like.