Occasionally, but more frequently, one hears of people practicing some form of fast. This is usually called a intermittent fasting which does not involve complete abstinence from food.
This practice is not necessarily chosen Weight lossbut also because it is commonly believed that fasting Done well to the organism. Is this correct?
Before we find out with the help of experts, let’s get clear What are the forms For potential intermittent fasting (also see chart below, Mr. Dr) because they affect the body differently. The most common are: one day a week, a few days a month, one meal a day, and hourly fasting. The most used method is the latter: 16 hours on an empty stomachIn the other eight, you eat with or without calorie restrictions.
Is it good or not?
What does the science say About the effects of fasting? Studies for years focused on the animal model (Laboratory rats, ed) and the first results indicate an important effect on longevity and the general well-being of the whole organism – he explains Elena Dogliotti– Nutritional Biologist and Scientific Supervisor of the Umberto Veronesi Foundation. Later, thanks to more evidence in humans, it was noted that fast They can have the opposite effects: they slow down metabolism, negatively affect circadian rhythm and hormone production, and can lead to malnutrition. Stefano Erzgovici“Male rats on a fasting diet were healthier and lived longer than rats that ate more frequently, but humans have a completely different functional complexity than that of a baby mouse.”
complete fasting, especially if it is done without medical supervision (but we’ll talk about it in more detail later, Mr. Dr), causes in the organism a severe stressAnd it’s not healthy: the body “stresses” itself to get the missing sugars, and so on Slightly lowers basal metabolic rate To “resistance” in the absence of resources e Raising the level ofCortisol, its excess (those who take cortisone know this well) can lead to its importance in the long run Both physical and mental consequences (Water retention, blood sugar imbalance, difficulty losing weight, decreased immunity, stomach erosions/ulcers and mood swings) ».
The guide leans towards Exclude total fasting and practice intermittent fastingbut also in this case it is necessary to distinguish: if complete abstinence from food causes stress in the organism (which can also be psychological, see below, Mr. Dr) The choice must be made on an “hourly” basis, and in any case it leaves limited space for “an empty stomach.”
However, we cannot talk about fasting without considering that Calorie restriction That this practice actually entails (eating less), in a society of abundance and fast food can only do in general: «Calorie restriction reduces risk factors for chronic diseases typical of our time (Cardiovascular diseases, obesity, diabetes II, tumors and neurodegenerative diseases such as Alzheimer’s) – considered Erzegovesi – because they activate specific responses Reducing indicators of the inflammatory conditionand those related to an increased risk of cardiovascular disease. Nevertheless, until now We cannot draw any conclusions that they ultimate About the effects of intermittent fasting, because the large personal variability makes it very difficult to analyze the results of these sometimes seemingly conflicting studies, ”says Dugliotti.
The second consideration that is generally true is that Eating little (or nothing) in the evening and eating dinner early are two remedies: For this reason, in the most commonly used form of fasting, which is 16:8 hourly, a distinction must be made. Skipping breakfast does not have the same effects as skipping dinner: «The metabolism of sugars and insulin follows our circadian rhythms, so eating in the range of 8-16 (when the sun is highest over the horizon) is the best thing – explains Stefano Erzgovici -. If you consume a lot in the afternoon and, above all, in the evening, you “run into” greater insulin resistance (and this concerns all people, not just diabetics), and, moreover, the evening meal closer to sleep makes the mechanisms of purging The brain that is activated at night, as well as sleep itself.
Good effects recorded
There is little really conclusive scientific evidence, but it is there Many points in favor of occasional fasts done according to some criteria (which we will explain later, Mr. Dr): can be a useful tool for Body weight regulation, circadian rhythms, and low-grade chronic inflammation. Then there are the observational studies (recording an association between behavior and the result obtained, without showing causal association) that list many of the benefits associated with intermittent fasting (with or without caloric restriction). “A lot of people talk about the best mental competence: It may be due to the increase in the levels of neurogenesis, the development of new brain cells and nerve tissue – says Erzegovesi -. An organism resting from the daily work of digesting food also manages to “burn” waste more efficiently, which is why one can feel less “bloated”».
negative effects
There are also “side effects”, including psychological ones. «Low blood sugarfor example – Erzegovesi continues – , glucose (sugar, ed) is the fuel preferred by our cells and which, when they have to feed on “temporary” fuels, can signal exhaustion. This decrease in blood sugar can also make you feel irritable “Angry ‘sad or irritable. Add to that the potential start of some heachachedue to ketosis (the metabolic state in which the body runs out of sugar).
The contraindications, in the case of some categories of people, are even greater: “Fasting affects circadian rhythms – adds Dogliotti – and the production of hormones, so it can have an impact Negative on the hormonal cycle, on fertility». «Fasting is a medical act – warns Erzegovesi – and as such it is not suitable for everyone: in stages of development (Minors and pregnant or breastfeeding women) Cells need a stable and stable energy source, so it should be avoided. Also, any form of calorie restriction can alter the absorption and amount of the active ingredient pharmaceutical which we take it It is also not recommended during convalescence or illnessbut Especially for those who suffer from a Eating disorders».
“The intermittent fasting system has been tested and is still being tested even during Oncology treatments – says Dr. Dogliotti – but even in this case it is very difficult to be able to draw statistically significant conclusions. The results seem to point to the fact that fasting during the acute phase of administration Chemotherapy strengthens healthy cells And weaken the sick, but it is not yet possible to say this to everyone. It should be characterized by the individual tumor type and the age of the patient. There are many differences.”
Does it make you lose weight?
the intermittent fasting It is successful because it is My work is easy And it can (possible meaning is underlined) it can be good, but in many cases it is used only as a “shortcut” with the aim of losing weight, within more or less balanced diets. Is it a good way to lose weight?
«There is no evidence Which shows us that the intermittent fasting system is better than the traditional diet Mediterranean diet with calorie restriction For a permanent result over time », notes Dugliotti and Erzegovesi confirms:« Le The evidence is not conclusive. And the most dangerous thing is that they follow the fast binge: Many patients cheat themselves, by spending a day or a few hours restricting calories, so that they can continue to eat Fast food The rest of the time, however, this is not the case.
However, in the case of a choice directed by a specialist, It is a good way to help lose weight Especially when calorie restriction does not lead to later “compensations” and may affect dinner (as written earlier, Mr. Dr).
Advice for people who do not have diseases
Some final advice can be given: “Relying on specialists, regarding nutrition related to diseases, and wanting to reduce fat mass,” repeats Dogliotti. “Fasting does not necessarily mean not touching food,” Erzegovici advises. The best option to practice it without “shock” Partial abstinence, such as 12 hours a day, one or more non-consecutive days a week, or caloric restriction that resemblesThe “lean days” of our grandparents, with snacks It consists of vegetables, “good” fats such as nuts, and extra virgin olive oil for dressing salads or vegetable purees ».
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