When we eat, it is for one of two primary reasons: hunger or appetite. What many people don’t know is that these processes are actually incredibly different.
Put simply, hunger is the need for food, while appetite is the desire for food.
What is hunger?
In an instinctive mechanism to protect the body, physical reactions take place when a person is hungry, because the body looks to ensure it receives the energy it needs to function properly.
This leads to chemical changes occurring which can result in blood glucose levels dropping a few hours after you have eaten.
What is appetite?
Appetite is a conditioned response to food, with a psychological or sensory reaction taking place. When you see food and think it looks good, or smells good, it can trigger stomach contractions or salivation, and these physiological responses are involuntary.
Appetite is responsible for you eating more food than you really need, such as when you eat one biscuit and then eat another because you enjoyed the taste so much.
Physical signals when the body wants food
When your body needs more food, physical reactions will take place, either in the blood or in your stomach. These are clear signs that your body desires food.
An empty feeling
Having lower blood glucose levels can cause an empty feeling as your body looks to consume glucose, and this can increase your appetite. Having low blood glucose levels can cause people to feel weaker, or fatigued.
Your blood glucose levels increase because your pancreas secretes insulin when you eat food. This hormone helps turn food into glucose, as well as helping the body use (or store) this simple sugar for energy.
Stomach rumbling and growling
A ‘hunger pang’ is the term used to describe your stomach issuing a loud, audible rumble, seen as a call for food.
It is the result of a process called peristalsis, which begins in the esophagus. A series of muscle contractions occur, with food being moved along the digestive tract by the waves that are produced.
When there is no food in the stomach however, the continual waves and contractions only squeeze air through the tract, which is what makes noise.