What is the identity of appetite and satiety? A diet method that is easy to succeed neuroscientifically


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What is the identity of appetite and satiety

Appetite control is important for a successful diet. A part of the brain called the hypothalamus controls appetite such as hunger and satiety. Here are some tips for putting brain science on your side and managing your weight in a healthy way.

Appetite controlled by the brain.

“Diet” seems to be a hot topic for many people, and not a day goes by without seeing diet-related TV shows and product advertisements. There are movements such as “body positivity” that positively affirm each body type, but the diet boom seems to show no signs of abating.

When asked what “dieting” means, many people may answer “to lose weight”, but that is not true. The word “diet” originally meant “meal, food,” and the term “diet” came to be used simply as a method of weight control through dietary restrictions. This may have given rise to the misunderstanding that “diet = lose weight”. Therefore, it is correct to call weight loss through dietary restrictions a diet, but it is actually strange to call exercise methods and health equipment unrelated to diet as “diet methods” and “diet products.”

Aside from that, the most important part of dieting is appetite control. And it is the hypothalamus in the diencephalon that plays that role. If you want to diet to maintain a healthy figure, start with your brain on your side. This time, I will explain in an easy-to-understand manner how the hypothalamus regulates appetite.

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Where do hunger and satiety come from? Roles of feeding and satiety centers

Appetite is regulated by the balance between the eating center, which produces the desire to eat “I’m hungry” and “I want to eat,” and the satiety center, which produces the desire to eat “I’m full.” As shown in the figure below, it is believed that the feeding center is mainly located in the lateral hypothalamus, and the satiety center is mainly located in the ventromedial nucleus of the hypothalamus.

The feeding and satiety centers that control appetite are located in the lateral hypothalamus and the ventromedial nucleus, respectively (original drawing created by the guide)For example, when there is no food in the stomach, the stomach secretes a hormone called ghrelin, which travels through the bloodstream to the distant hypothalamus feeding center in the brain to notify it. In addition, when the state of hunger continues, fat in the body is broken down and fatty acids are released, which stimulate the feeding center. Appetite increases when the feeding center works.

On the other hand, when the stomach is full of food, the abdomen is compressed, and the stimulation is transmitted to the satiety center. Also, when the carbohydrates eaten are digested and absorbed and the concentration of glucose in the blood rises, nerve cells in the satiety center with glucose sensors respond. Furthermore, when energy accumulates in the body, a hormone called leptin is secreted from fat cells, and it works on the satiety center. And when the satiety center works, satiety occurs and stops eating.

Effective in preventing overeating! Eating slowly makes you feel full

It’s often said that “fast eating makes you fat”, and in a way it’s true. Why is it said that if you eat your food without chewing it well because you are hungry or you don’t have time, you will gain weight easily?

Time is key. If you eat slowly, amylase, a starch-degrading enzyme contained in your saliva, will act while you are chewing well in your mouth, and polysaccharide starch will be decomposed into disaccharide maltose in advance. Therefore, after food reaches the stomach, it does not take long for it to be converted into the monosaccharide glucose in the intestine and absorbed into the body. On the other hand, if the food is swallowed without chewing well, the amylase does not work and the starch is transported to the gastrointestinal tract as it is. Therefore, after food reaches the stomach, it takes time for the starch to be broken down into glucose in the intestines, which delays the absorption into the body. In other words, the time it takes for the satiety center in the hypothalamus to detect that the blood sugar level has risen after the start of eating is longer for the latter, which appears to be eating faster, and the feeling of fullness is delayed. is.

It may come as a surprise, but chewing your food slowly and thoroughly fills you up faster, so you eat less. If you eat quickly without chewing, it will take longer for you to feel full, and you will eat more during that time. On top of that, if your stomach is too full, it will be troublesome to move, and you will fall asleep.

Chew your food slowly and thoroughly to stimulate the satiety center in the hypothalamus.

Illness and stress can also have an effect…the imbalance can lead to overeating or anorexia

If the eating center and the satiety center work in a well-balanced manner, there is no problem, but if there is an abnormality, the appetite cannot be controlled well, and it may lead to overeating or anorexia. For example, patients with Prader-Willi syndrome have abnormal secretion of ghrelin, which stimulates the eating center. It will end up.

Emotional stress can cause overeating or anorexia, even if you’re not sick. When the state of tension continues due to stress, the sympathetic nervous system is dominant in the autonomic nervous system, so appetite decreases.

If the stress continues for a long time and becomes chronic without being resolved, it can lead to bulimia. It is thought that the action of leptin, which stimulates the satiety center, is dulled, resulting in an uncontrollable appetite. It’s not a good idea to go hungry.