True. Hunger just like any other emotion in the body is a chemical reaction that occurs within the brain. This signals the body that it is in need of nutrients essential for many organ system functions. There are many chemical processes within the body that need essential nutrients (eg. carbohydrates, fats) to perform efficiently. Without food, the body will be weak and there will be complications within the internal organs. Hunger is a natural behavior of all living organisms and is essential for survival and overall a major cause of evolution.