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Rejuvenating Effects: What are the hidden effects of 16-hour fasting that go beyond dieting?

Rejuvenating Effects: What are the hidden effects of 16-hour fasting that go beyond dieting?

Fasting" is becoming popular among people who are interested in health and diet, and there are various types of fasting, such as 16-hour fasting, petit fasting, and Monday fasting. Among them, the 16-hour fast is expected not only to help people lose weight but also to rejuvenate them. Why is 16-hour fasting good for the body? Let us explain the mechanism.


1. What is a 16-hour fast?

16-hour fasting is a health practice

16 Hour Fasting" is a health practice in which people fast for 16 hours in a day.
Dr. Atsushi Aoki, a medical doctor and the current director of the Saitama Diabetes Clinic, wrote a book titled "Fasting is the Greatest Drug" that made people aware of its effectiveness and merits, and it became a topic of conversation.
Although the new coronavirus may have changed the rhythm of some people's lives, it is still a challenge to eat three meals a day on a daily basis in today's society without compromising one's health.

Nevertheless, the 16-hour fast is attractive because it can be adopted with a little awareness, for example, by having dinner earlier in the day or shifting the timing of breakfast.
Moreover, if science has proven that it conditions the body and turns on the rejuvenation switch, we couldn't be happier.

Let's look at the mechanism of how the rejuvenating effects of fasting, including 16-hour fasting, are achieved.


2. "Acceleration of growth hormone secretion by hunger" that has a rejuvenating effect

If you go for a long time without eating, you may feel a "rumbling" in your stomach.
This hunger leads to the secretion of growth hormone, which has a rejuvenating effect. This is one of the reasons why 16-hour fasting or fasting is said to be effective for rejuvenation.


2-1. Mechanism of Growth Hormone Secretion

The "grumbling" of the stomach on an empty stomach is called hunger contractions. This "gulp" is the sound of the stomach contracting and trying to push out food that may still be in the stomach into the small intestine.
The absence of food from the mouth activates the food sensor at the entrance to the small intestine, which releases a digestive hormone called motilin.
The first challenge at the beginning of the 16-hour fast is to overcome hunger by cutting off food temptations, which can be both painful and embarrassing. This painful and embarrassing belly rumbling is the time to persevere in order to be rejuvenated from the cellular level.

Gulping on an empty stomach is the first step toward rejuvenation.

2-2. Hunger is the priming of "rejuvenation hormones

The stomach, sensing that it is truly empty due to the motilin secreted during hunger, now secretes the hormone ghrelin.
Ghrelin has the function of increasing appetite and promoting weight gain.
It also acts on the pituitary gland of the brain to promote the secretion of the key hormone "growth hormone," as the etymology of the word "grow" indicates.

Growth hormone, also known as "rejuvenation hormone

The growth hormone thus secreted is responsible for many important functions in our lives, and is also called the "hormone of rejuvenation" because it works to activate metabolism, break down body fat, synthesize muscles, and maintain skin elasticity.

2-3. 16-hour fasting is the perfect way to stimulate the secretion of growth hormones.

The peak of growth hormone secretion is during puberty, when secondary sexual characteristics occur, and its secretion declines rapidly with age.
By the 40s, it is half of its peak level, and by the 60s, it declines to about 20% of the adolescent level.
As growth hormone secretion declines and metabolism slows, body fat increases, muscles decrease, skin loses its texture and firmness, and the body ages.

The 4pm fast is perfect for rejuvenating hormones.

In order to quickly obtain the rejuvenating effects of this growth hormone, many cosmetic surgeons use direct external injections of growth hormone.
Growth hormone decreases after adulthood, and methods to increase its secretion on one's own include 16-hour fasting, KAATSU Training, muscle training, and other forms of exercise.
However, we recommend the 16-hour fast because it is relatively easy to tackle.


3. "Activation of autophagy," a fascinating effect of 16-hour fasting

Autophagy is the process of autophagy and cleansing of bad proteins in the cells.
When food does not enter the body due to fasting or fasting for a long period of time, you may feel a strong sense of hunger, but it is not just a feeling in the stomach or brain.
Let me tell you how autophagy works.


3-1. Rejuvenation through activation of autophagy

Autophagy, the Key to Rejuvenation

Let's fine-tune our perspective a bit and look at the body at the molecular level.
When the stomach is emptied, in addition to physical hunger, physiological hunger is heightened by a drop in blood glucose levels.
Finally, approximately 12 hours after the last meal, all the cells in the body are no longer nourished, and even the cells begin to detect starvation.
Then, in order to provide nutrition within their own cells, the starved cells begin to break down the deteriorated or broken parts of the cells, and also activate a mode of recycling so that the parts can be reused within the body.
In this way, the cells themselves refresh and rejuvenate all the cells in the body.
Recently, it has been discovered that the cells also decompose bad germs that have invaded the body, and this can even improve the immune system.


3-2. Autophagy, the Key to Anti-aging

Autophagy is a phenomenon that normally occurs in the body, but it is a function that was originally built into the body to survive under severe stress in a harsh environment.
To promote the activation of this survival ability, it seems to be difficult without a certain amount of stimulation, such as exposure to high temperatures and hypoxia, in addition to 16-hour fasting.
The function of autophagy itself has been discovered 40 years ago, but its detailed function has only recently been elucidated. Autophagy was a black box until then.
The mechanism of action of autophagy, which until then had been a black box, was discovered and published by Professor Emeritus Yoshinori Osumi of the Tokyo Institute of Technology, who was awarded the Nobel Prize in 2016.
Even today, much research is being conducted on autophagy as a major key to preventing aging and disease.

4. "Sirtuin gene," the key to anti-aging

The sirtuin gene is present in many living things, including us mammals.
It is also called "longevity gene" or "anti-aging gene" because it is a gene that has been confirmed to prevent aging and extend life span by repairing old cells and removing active oxygen that causes aging.
When this sirtuin gene is activated, in addition to the activation of autophagy described earlier, DNA repair takes place everywhere, preventing the creation of aged cells.

Sirtuin gene, the key to anti-aging

4-1. 16-hour fasting activates the sirtuin gene

Since the sirtuin gene is normally dormant and not working, it is necessary to switch on the dormant sirtuin gene in order to activate it.
There are two major conditions for activating the sirtuin gene: one is moderately strenuous exercise, and the other is hunger or starvation.
Putting aside nutritional balance, people living in Japan and other developed countries have enough energy to survive on a normal diet at a normal standard of living.
In order to activate the sirtuin gene on our own in such an environment, we need to stress our cells by exercising or fasting for 16 hours.

5. Characteristics of people for whom 16-hour fasting is suitable

The 16-hour fast is not only effective for weight loss, but also for rejuvenation. We would like to share with you the characteristics of those who are suited for this program and would like you to incorporate it into your daily life.


5-1. Lifestyle habits of those who are suitable for 16-hour fasting

Dietary habits of people who are suited to 16-hour fasting

1. You eat out a lot, such as Western or Chinese food, and consume a lot of animal products
2. You habitually eat and drink too much and often have gastrointestinal upset the next morning
3. You eat a lot of snacks outside of meals and snacks are a daily habit
4. You have high blood sugar, high blood pressure or metabolic syndrome

1 and 2 apply "If you are prone to excessive calorie intake on a regular basis, this places a greater burden on your organs and makes it harder for intracellular recycling to occur.
First of all, you may try to adopt 16-hour fasting with the aim of reducing the total calorie intake, preventing lifestyle-related diseases, and reducing the burden on the internal organs.

3's, who have a habit of snacking due to snacks as a luxury item rather than for the purpose of maintaining body energy or nutrition, maintain fasting time, You may also fast for 16 hours to normalize blood glucose levels and prevent insulin wasting.
However, autophagy is already suppressed in people with lifestyle-related diseases, so fasting may not be expected to have an immediate effect on cell purification and recycling.

In addition, for those who have a greasy and heavy diet and frequently have dinner late at night, it is recommended to start by increasing the frequency of meals based on Japanese food and keeping the fasting time at 12 hours, without forcing yourself to fast for 16 hours. If you have any trouble with the content of your meals, it is definitely a good idea to eat with "Magowa Yasashi" in mind.

5-2. Physique of a person suitable for 16-hour fasting

1. You have sufficient muscle mass and are physically fit.
2. You are in the normal to obese body type with a BMI of 20 or higher.
Those who are suited to 16-hour fasting in terms of their physical constitution and physique are those who were members of an athletic club during school or have a regular exercise routine as adults and have sufficient muscle mass and physical strength.
Even if you are of normal build with a BMI of 20 or above, it is wise not to do the 16-hour fast if you meet any of the characteristics of those who should not fast for 16 hours as explained below.

6. Characteristics of people who should avoid 16-hour fasting

Who should not fast for 16 hours?

Although we have told you that 16-hour fasting is scientifically effective for rejuvenation, unfortunately, not everyone is suited for 16-hour fasting, and we will tell you the characteristics of those who should avoid 16-hour fasting.

Eating habits of those who should avoid 16-hour fasts

6-1. Lifestyle habits of those who should avoid 16-hour fasting

1. You usually finish your meals with instant foods or food items alone.
2. You do hard physical work all day long.
3. Your body or brain gets tired easily and you cannot give up sweet snacks as your favorite food.

If you fall under 1 above, "You finish your meals with instant foods or food items alone." If you fall into the first category above, it is possible that your nutritional condition is not very good or your body is in energy-saving mode.
If you fast for 16 hours in that state, you may not feel well.
If you do engage in it, make sure that your daily energy intake is not less than 60% of your needs.
In terms of calories, this is a diet that will ensure that the least energetic women get 1200㎉ and men get 1500㎉.

Secondly, if you are a person who does manual labor or cannot give up sweets, you may not be able to get enough nutrients for your body, which may interfere with your work and daily life. This may interfere with their work and daily life.
Some people cannot even tolerate hunger for more than 4 hours and need nutritional supplementation.
For such people, fasting can cause cellular fatigue, so they should avoid fasting and maintain their vitality by adopting a lifestyle that incorporates nutritious complementary foods.

6-2. Physique of those who should avoid 16-hour fasting


1. You fall into the thin category with a BMI of 20 or less
2. You are not confident in your physical fitness and have little exercise experience since school
3. You are an athlete seeking recovery and muscle hypertrophy immediately after hard training
4. You are pregnant or nursing

If you are originally thin in 1. and the 16-hour fasting causes you to miss food, your nutritional status If the 16-hour fast results in food deprivation, the nutritional status may worsen.
In addition, those who fall under 2, who have low muscle mass and lack confidence in their physical strength, tend to have low carbohydrate stores in their bodies and are not very good at producing energy on their own when they run out.
If those who fall under 1 or 2 are going to fast for 16 hours, they should not do it every day, but only a few times a week. In addition, the 16-hour number does not include the time that you need to fast for 16 hours.
In addition, it is recommended that you allow yourself as much fasting time as you are able, and not just 16 hours.

For athletes who have just completed a hard workout or are training for muscle hypertrophy, it is recommended that they fast for 16 hours to allow their bodies to recover. Recovery is the first priority for "those who train for muscle hypertrophy.
Immediately after training, the body's immune system is temporarily weakened and the resynthesis of destroyed muscle is more active.

16-hour fasting is not suitable immediately after hard training or for athletes.

At such times, it is dangerous to implement a 16-hour fast to lower amino acid levels in the blood.
This can lead to a cold or muscle aches that do not heal well because of insufficient nutritional support for recovery.
Light exercise during the fast is good for activating autophagy, but not immediately after hard training at an athlete's level.
If you want to fast for 16 hours for the purpose of autophagy, it is advisable to do so avoiding immediately after hard training that leaves you feeling fatigued, or only on weekends as maintenance.

If you are pregnant or breastfeeding, which corresponds to 4, it is important to take in enough nutrition daily. It is important. If a pregnant mother has low blood sugar or is underweight, the fetus in her belly will grow up under constant starvation. Then, after birth, that child is at a higher risk of developing numerous diseases in the future, including myocardial infarction, stroke, type 2 diabetes, hypertension, and obesity.

First of all, for your own health and for the future of your precious child, avoid 16-hour fasting during pregnancy and lactation, and eat well to avoid low blood sugar and nutritional deficiencies.


I have explained the mechanism of why 16-hour fasting not only helps you lose weight but also rejuvenates you. Once you understand the mechanism, I believe you will be able to tackle 16-hour fasting more efficiently. Please make it a part of your daily life, turn on the autophagy and sirtuin gene activation switch, and get a younger looking body.

Check out ▶︎ "Dieting and Rejuvenation! Check out this article on how to do the "16 Hour Fasting": ◀︎

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