This source of food was essential for man’s existence, since all cereals ​ — including wheat, barley, rye, oats, rice, millet, sorghum, and maize — ​ contain starchy carbohydrates that the body is capable of transforming into its principal fuel ​ — glucose.
See toiduallikas on inimese eluks hädavajalik, sest kõik teraviljad – nende hulgas nisu, oder, rukis, kaer, riis, hirss, sorgo ja mais – sisaldavad rohkesti tärklist, süsivesikut, mille organism muudab oma peamiseks energiaallikaks – glükoosiks.