Hunger is one of the most primitive urges any animal, humans included, can feel. It can be both a psychological and physiological response to stimuli. Before a person can be able to eat, something has to motivate them, which can be multiple things in the outer environment and their inner mind. .
All people have felt hungry at one time in their life or another, even if they cannot remember it Ho many times does a baby cry for food or instinctively reached for its mother when someone touches its cheek also known as the rooting reflex. It is an act of self-preservation for us to feed ourselves. Researchers during WWII found that prisoners of war would unconsciously conserve body energy when their rations were cut in half, even to the point of not laughing or smiling. The body was trying to keep as much energy as it could for itself since it didn't know when it was going to be fed again.
Hunger is a very intricate part of any animal's body chemistry. When the stomach is digesting, it contracts a grinds the food into little pieces, which are then sent to the intestines to be digested. When it is empty, the stomach will essentially try to digest itself, which is why when someone is very hungry their stomach will actually "growl". Two scientists, Washburn and Canon wanted to test this theory. Washburn swallowed a balloon that was filed with air. He was told to push a button each time he felt hungry. The balloon confirmed that every time his stomach contracted, that was when he felt hunger.
Even an animal with is stomach removed will still be just as hungry and eat just as much. When the body is low in glucose, the part of the brain in charge of hunger and sex, the hypothalamus, will send out messages that it is time to eat. The hypothalamus is divided into two parts. The lateral hypothalamus is in change of telling the body to eat If this is damaged or removed, the animal, including humans, will die of starvation because it cannot process hunger.
