Intermittent Fasting: Benefit Or Harm

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Intermittent Fasting: Benefit Or Harm
Intermittent Fasting: Benefit Or Harm

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Video: Intermittent Fasting - Fact or Fiction? What the Science Actually Says 2022, December

Despite the skyrocketing popularity, intermittent fasting is far from new. It has existed for many tens (if not hundreds) of years, and all this time the disputes between its adherents and opponents have not subsided. The essence of intermittent fasting is simple - the day must be divided into two time intervals. During one of them you need to eat, during the second - to starve.


Depending on the alternation of two time phases, the following power schemes are separated (we have chosen the most common):


The "16/8" scheme is the most popular - it implies a daily fast for 16 hours (there are only eight hours left for food). For example, a person eats between 12 and 20 o'clock, and the rest of the time he is starving. As a rule, such a scheme does not include breakfast and consists of 3-4 meals.


Option "14/10" is considered the simplest and most gentle. 14 hours of hunger alternate with 10 hours according to the principle "everything is possible." Intermittent fasting adherents recommend starting with this scheme and only after it try more complex options.


The "20/4" scheme includes a four-hour food window and a twenty-hour hunger. For example, a person eats between 2 pm and 6 pm, and the rest of the time he drinks water (sometimes indulgences are allowed in the form of freshly squeezed vegetable juices and nuts). As a rule, in this case, either one large meal is assumed, or two small ones.


Scheme "24" is fasting between meals. So, if today a person had breakfast at 11 o'clock in the morning, then the next time he should eat tomorrow morning at 11 o'clock. Yes, a person eats daily, but only once. Such fasting should not be carried out more often than two to three times a week.


The 5/2 scheme was developed by Michael Mosley, author of The Fast Diet. Mosley recommends eating everything you want for five days, and restricting yourself for two days - while on the "days of hunger", according to his method, you can eat up to 500 calories. They can be stretched out for the whole day or eaten as one meal. In fact, there is no innovation in his theory, it is based on the principle of calorie deficit - a situation when the diet is composed in such a way that a person spends more calories than he consumes.

An important clarification: the controversy about intermittent fasting erupted with renewed vigor after Japanese scientist Yoshinori Ohsumi received the Nobel Prize in Medicine and Physiology in 2016 for his work on the mechanisms of autophagy (translated from Greek means "self-eating") - the process by which a cell gets rid of defective proteins and organelles. While experimenting with ordinary baker's yeast, the scientist found that the level of autophagy in the cell directly depends on the overall energy level: during fasting, the body breaks down old or damaged proteins more intensively, turning them into a source of energy and growth. It was this discovery that led to the fact that many people began to deliberately enter their body into a state of hunger in order to accelerate the process of cell renewal.

But to what extent such measures are justified and, most importantly, safe, we decided to ask Elena Motova, a nutritionist at the Rassvet Evidence-Based Medicine Clinic, author of the book My Best Friend is the Stomach. Food for smart people."

Elena Motova - Autophagy occurs constantly in the cell, however, it sharply increases during starvation, exposure to radiation and toxic substances entering the cell, due to which its structures are damaged. In Osumi's laboratory, the genes responsible for this process were isolated, then the mechanisms of autophagy were studied in mice. The fundamental study of physiological processes (so far in animals) does not in any way concern human nutrition. Doesn't apply at all.Perhaps, over time, these processes will help to better understand the mechanisms of aging or will be used to fight cancer cells, which, despite the most aggressive influences, multiply uncontrollably and lose their ability to die. In general, further research is needed.

It has been known for many decades that limited nutrition in laboratory animals - rats, mice, hamsters, and even yeast - increases their average and maximum life expectancy. But these animals live only a few years - yes, it is much easier to obtain data, but it is completely incorrect to distribute them to humans. There are no human studies showing how fasting affects life expectancy (and its long-term effects remain unknown). In addition, this style of eating has a number of contraindications, such as diabetes (and other metabolic diseases), cholelithiasis, and eating disorders. It is not recommended to starve for children, pregnant and lactating women. Before trying any extreme nutritional system on yourself, it is worth consulting your doctor.

There is only one more or less long-term study of fasting (not too many people took part in it, but there were even fewer in other similar studies). His goal was to compare fasting with normal caloric restriction in the diet. One hundred overweight and obese volunteers were divided into three groups - two experienced and one control. For 12 months (this is how long the observation lasted), participants in both weight loss groups lost weight about the same; there were no significant differences in biochemical markers between them. 38% of people dropped out from the fasting group, 29% from the calorie restriction group. Unfortunately, there was no further follow-up of the participants. The bottom line is that you can lose weight on any diet, but the biggest problem remains to maintain the achieved results. When a person stops following the principles of a particular diet, he gradually regains the lost weight. So before you start fasting, ask yourself if you can stick to this eating style for the rest of your life. Hunger is hard to ignore and does not guarantee sustained weight loss. And by itself, eating once a day may not affect weight at all. - It should be remembered that all participants in fasting studies were under constant medical supervision and regularly consulted with nutritionists. In ordinary life, people themselves prescribe diets, having little idea of ​​how digestion works, hormonal regulation of appetite and energy metabolism. In our body, adipose tissue can be located under the skin (subcutaneous fat) and in the abdominal cavity, surrounding the internal organs (visceral fat). Excessive deposition of internal fat in the abdomen leads to an increase in waist circumference and is manifested by an "apple" figure - one that can occur both in men, at any age, and in women (mainly after menopause).

If the waist exceeds 80 centimeters for women and 94 centimeters for men, it is customary to talk about central (abdominal) obesity. Such obesity is associated with an increased risk of heart and vascular diseases, type II diabetes mellitus, and metabolic syndrome. Visceral adipose tissue is not just energy stores, but also a source of signaling molecules that control metabolic processes. Reducing the amount of internal fat in people with abdominal obesity improves the sensitivity of cells to insulin. This has been well studied in people with prediabetes and type II diabetes. However, different dietary approaches can be used here, and not just intermittent fasting (which is not included in any dietary recommendations). The main thing is that the results of the intervention are sustainable.

- Of course, moderation in diet, a balance between food intake and energy expenditure is an excellent option for maintaining health and stable weight. However, for this, it is necessary to form such an eating behavior that will allow you not to eat more than you really need on a regular basis.

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