Most of our grandparents or great-grandparents who experienced both World Wars and the Great Depression practiced these ideas in their kitchens including gardening for most of their fruit and vegetables; many home-keeping books at the turn of the century through the '40's encouraged the wise use of food. It appears that only in the era of great abundance between World War 2 and today that waste has become common and accepted, in America especially.
In the fifties, a restaurant hamburger was the size of a "junior" hamburger today - no wonder people were slimmer! No one thought of "super-sizing". Older cookbook serving sizes were much smaller than those of today as well. Housewives filled out the meal with vegetables instead of huge main dish portions.
When we lived in Europe, we didn't see the wasteful use of food, even in well-developed and wealthy countries. Many Europeans only shopped a day or two ahead, prefering to buy or grow fresh food. They also don't have huge refrigerators and other appliances, because utilities are so dear.
Good managers will try to practice these rules in their own kitchens, especially in these now less certain times. Learning to cook from "scratch" is important for our health and our pocketbooks. I might suggest that relaxing around the dinner table with family and friends, enjoying conversation and fellowship, is also good for our well-being.
She looks well to the ways of her household. Proverbs 31:27