are staple foods in most societies. They form the bulk of what we eat. From breads to cakes to rice and barley, they are usually the type of food that we take to relieve our hunger, supplemented by consumption of vegetables and meats.
Surprisingly, the growing of grains goes back only about ten thousand years. Before then, humans were primarily hunter gatherers who depended on killing animals for meat, and collecting fruits and berries for the nutrients. The introduction of grains consumption has radically transformed out diet, for better and for worse. In any case, it's something that we can't do without today.