It is the time of year when we in America celebrate Thanksgiving, which is completely based around the necessities of food & family. As humanity advances and situations change, who knows what kind of food-based innovations & customs will arise?
Legendary science fiction writer Isaac Asimov envisioned a possible future in his book, "Prelude to Foundation" At the Galactic Capital world in the story, food was for a time grown using microorganisms. The nutrients were created from vats of yeast & algae, then flavored.
Yeast is already grown & used as a food product with many nutritional properties. However, it cannot currently be used a singular source of nourishment.
In the future, perhaps people will be able to refine the production of this yeast, or other microorganisms, to yield more benefits.
Self Nutrition Data: