How does the intermittent fasting regimen work?

The popularity of intermittent fasting is breaking records. The essence of the method is a long time interval between the last and first meals . Intermittent fasting schemes vary, but the most popular is 16/8 – when the break between dinner and breakfast is 16 hours.

Interestingly, intermittent fasting is not the result of the development of nutritionists, but a by-product of a medical experiment.

The basis of intermittent fasting is the process of autophagy

In Greek, autophagy means “self-eating”. Moreover, only in a positive sense – this is how the body gets rid of damaged, defective and old cellular structures.

The phenomenon of autophagy was discovered back in the 60s of the last century. But it wasn’t until 2016 that Japanese professor Yoshinori Ohsumi made a startling discovery while investigating the process of autophagy in yeast cells. He discovered genes whose destruction led to defects in the formation of autophagosomes.

By observing the behavior of yeast cells, the scientist noticed that stress, in this case hunger, stimulates autophagy and cell renewal processes. With a lack of calories in the cytoplasm of cells, autophagosomes are formed – vesicles with a two-layer membrane, a kind of “garbage bag”. Then they merge with lysosomes, forming autolysosomes, in which degradation occurs – the destruction of macromolecules and organelles.

As a result, old cell structures are destroyed, new ones are created, metabolism is accelerated, a person feels more cheerful, younger and slimmer.

Mechanism of intermittent fasting

This action of autophagy is the basis of the intermittent fasting scheme, when due to stress – lack of nutrition, the cell begins to “eat” itself. At the same time, first of all, old, damaged structures fall under distribution. And the cell itself is actively updated – rejuvenated.

Cell renewal begins with fasting from 12 to 36 hours. If you fast for less than 12 hours, the autophagy process will not start – the cells will have enough nutrients from food. Therefore, it is important to endure a break in food for 12-14 hours or more.

But if the fasting period exceeds 3 days, the metabolism slows down, the body goes into saving mode, and seeks to maximize the use of calories, putting them in the fat depot, in reserve.

The most popular and safe intermittent fasting schemes

Of all the intermittent fasting regimens, the safest are those that correspond to the physiological clock of the body, these are 14/10 and 16/8.

  • In the first case, a person is without food for 14 hours, and 10 hours falls on the so-called window for eating. For example, the first meal is breakfast at 8 am, the last meal is dinner at 6 pm.
  • The second option for the 16/8 intermittent fasting scheme is breakfast at 9 am, dinner at 5 pm.

The first option of intermittent fasting 14/10 is more gentle. They resort to it if it is difficult to withstand 16 hours without food. During the “hungry” 14 or 16 hours, you can drink only water or tea without sugar.

At what time of the day to refuse food – does not play a role. The main thing is to endure the fasting period. Only when all the food leaves the digestive tract, the body will begin to replenish energy reserves, utilizing the old cellular structures. But, based on our physiology, it is reasonable that the main hours of fasting fall at night, when the body is resting.

The 14/10 and 16/8 intermittent fasting regimens are ideal for beginners, both women and men. A person does not feel hunger, because the body still has a sufficient supply of glucose, and the body continues to function in a comfortable mode.

But there are other, more stringent fasting schemes.

Features of other fasting regimens

In other schemes, for example, in the 18/6 and 20/4 variants, the “food window” is significantly smaller. Beginners are not recommended to start with such schemes. But if there is experience with cyclic fasting, 18/6 intermittent fasting can be practiced for 3-4 weeks, and the 20/4 regimen can be practiced for no more than one week.

Those who want to get the fastest effect use the 24/0 and 36 options.

There is also a long-term intermittent fasting scheme, when a person eats as usual 5 days a week, and either fasts for two days or cuts the diet to 500-600 kcal. For example, Monday, Tuesday, Thursday and Friday – good nutrition, Wednesday and Sunday – fasting or diet cut to a minimum.

Such a diet, if desired, can be followed constantly, without time limits. The main thing is that between the days of fasting there are two days of good nutrition.

Who should not use intermittent fasting

It is impossible to apply intermittent fasting schemes with insufficient body weight and for those who are diagnosed with:

  • chronic diseases of the gastrointestinal tract (gastrointestinal tract);
  • disorders of the immune system;
  • diabetes;
  • ischemia;
  • hypotension;
  • depressive states.

Also, the interval diet is not suitable for women with impaired fertility (an indicator of the health of the reproductive system), pregnant and lactating women.

Experts warn: for those who are genetically predisposed to gallstone disease, intermittent fasting is not suitable – the disease may develop or worsen.

For people at risk, it is more physiologically fractional meals in small portions and regular physical activity.

Intermittent fasting and training

The process of autophagy triggers stress. Training is also stressful for the body, so do not forget about physical activity. Fitness classes will trigger autophagy, enhance its action and remove toxins from your body.


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