Illustrated Family Medical Encyclopedia - Understanding Our Body. Preventing Common Diseases

Author: Kaneko Jinsei
Publisher:
Publish Date: 2006-08-01
Features:
● Signals for Energy Supplementation
Appetite is an emotional and mental desire to eat something. It is well-known that appetite is one of the fundamental desires of humans. Eating is to obtain energy, which maintains and constitutes the bones, muscles, blood, etc. of the human body, promotes growth, and keeps the body active. It is an essential behavior.
What happens if you don’t eat? The human body obtains energy by burning sugar to perform various activities. Fasting disrupts the supply of sugar, so the body first breaks down glycogen stored in the liver and muscles. If this is not enough, the body may even begin to break down proteins as an energy source.
Since proteins are the basic elements that make up the human body, if they are used as energy, it will not only lead to weight loss but will eventually result in the inability to sustain life. By the way, if weight decreases by 40%, life cannot be sustained.
To prevent this from happening, after exercise depletes the energy stored in the body, the body sends a signal indicating that energy is low and needs to be replenished. This signal is hunger.
● Appetite is Controlled by the Brain
Generally, appetite is mostly caused by hunger, but it doesn’t mean that appetite is the same as hunger. For example, when appetite is excessive due to a certain disease, even if you feel very full, appetite does not decrease. Conversely, if appetite is poor, there is little appetite whether or not you feel hungry.
The human body usually transmits changes in nutrients in the blood, changes in body temperature, the utilization of glucose in capillaries, and other conditions to the hypothalamus, located in the lower part of the brain, specifically the lateral hypothalamic nucleus (hunger center) and the medial hypothalamic nucleus (satiety center), to determine whether eating is needed. For example, when glucose utilization is high (high blood sugar), it stimulates the satiety center and inhibits the activity of the hunger center. Conversely, it activates the hunger center to increase appetite.
However, when the hypothalamus is abnormal due to mental stress, trauma, or disease, this information cannot be transmitted smoothly, leading to the abnormal appetite mentioned earlier, ignoring the physiological condition.
Furthermore, signals from the hypothalamus are also transmitted to the brain’s limbic system, where they are influenced by various information obtained from sensory organs such as vision, taste, smell, touch, and hearing, and are transformed into specific appetite. In recent years, it has also been discovered that hormones such as insulin and fatty acids, in addition to glucose, are sources of information that affect appetite.