Things that have nourished people include these three. Sourdough, Polenta, and Commonplace Books. Two are simple foodstuffs, one is a keeper of the knowledge. All of them sustain people.
Sourdough is, or so it seems, simple. You mix flour and water. You wait. You add more flour and water. Then, eventually, it is filled with bubbles. There you have it. The thing that will raise your bread is ready to use.
Polenta, today, is coarsely ground yellow maize, coarse cornmeal. It is sustaining because you can eat it hot, like oatmeal. Or allow it to cool and become a loaf that can be grilled, fried, or roasted with topping to suit. Prior to corn being imported from the new world other grains had the same uses. Chestnuts, millet, chickpeas, and others were used. It is a flexible grain. You can include olive oil or butter, chopped jalapenos, a cheese of choice, these are the simplest of ways to modify polenta.
Commonplace Books is the way of keeping knowledge. Particularly, it was used by women before they were allowed to attend universities. There are notes in the margins of cookbooks. There are scrapbooks. There are books not know by this name. Do you have one? More? It sustains your personal knowledge base.
What sustains your life? These are three that sustain my life.