Oats or barley are both CEREAL grains that have been used for centuries as a staple food in many cultures. Oats are a type of grass that is grown for its edible seeds, while barley is a CEREAL grain that is used to make beer and other alcoholic beverages. Both grains are high in fiber and protein, and can be used in a variety of dishes. They are also used to make breakfast cereals, breads, and other baked goods.