It has long been believed that eating small, frequent meals is good for your health and figure. Recently, however, intermittent fasting has become popular among celebrities and business leaders. Can you help your body without giving up the habit of eating delicious and satisfying meals, just by changing your eating schedule? The temptation is great. Let’s look at the pros and cons of this method.
There is some evidence that intelligently applied abstinence can help you lose weight, improve your health, and even prolong your life, but nutritionists urge caution. The main purpose of intermittent fasting is to refrain from eating in the evening, thus increasing the interval between the last and first meal. Its advocates usually refer to the number 16 hours. Some focus on the quantity of food, promoting the “5:2 diet” (eating normally five days a week and reducing calorie intake by four times on the other two days).
“Temporary restrictions are used as a weight loss tool, but I can’t say it’s my favorite approach,” says Rachel Clarkson, founder of London-based consultancy DNA Dietitian. “You are reducing the number of calories, but not changing your approach to what you are putting into your body.” According to her, without understanding what a healthy diet is, people quickly regain their previous weight after fasting. “If you feel hungry and perceive it as a restriction, you are likely to overeat the next day,” she stresses.
Intermittent fasting may not be the best way to stay slim, but it has other advantages. It is associated with autophagy – a natural process of regeneration that occurs at the cellular level and is of great interest to scientists for its potential benefits to humans. We explain quickly, simply, and clearly what happened, why it matters, and what happens next. Episodes End of story: Podcast Advertising. Autophagy (“self-eating”) is a natural mechanism for dismantling and processing excess and non-functional parts within living cells, including nuclei, which store DNA; mitochondria, which convert nutrients into energy; and lysosomes, which remove waste products. The body gets rid of toxins and receives beneficial substances. Some of them turn into protective proteins that increase the longevity of cells.
Scientists are trying to determine whether autophagy contributes to the lifespan of the entire organism. It has been shown that suppressed autophagy leads to premature aging, but this data has only been obtained in experiments with mice and millimeter-long nematodes. To test this hypothesis in humans and confirm the link between autophagy and intermittent fasting, long-term observations are needed. Animal experiments confirm that autophagy also improves immune memory and probably suppresses cancer development.
For most of us, this process takes place in a dream. It is also stimulated by physical exercise and deliberate malnutrition. Can controlled abstinence activate it? Unlike diets that involve reducing the amount of calories consumed (which is also associated with longevity), intermittent fasting aims to increase the time between dinner and breakfast. Theoretically, his fans consume the same number of calories, although Rachel Clarkson notes that in practice, her observations show a negligible decrease. The important thing is what happens after you eat. “After eating your last meal at 7 p.m., you will remain full until about 10 p.m. as your body continues to digest the food,” she says. “Each carbohydrate provides a good amount of glucose, the body’s main source of energy, which lasts for several hours.” Feeling full means that glucose has entered the bloodstream and is being converted into energy. When it is depleted – which typically occurs about three hours after eating – the body enters a catabolic state, meaning it begins to convert polysaccharides stored in the liver and muscles into glucose. When both glucose and this energy source are depleted, the body switches from glucose to ketones, which are produced by the liver from fatty acids. This state is called ketosis, and it is at this stage that autophagy is activated.
Even the lightest snack at bedtime will prolong the feeling of fullness, so you may not be able to achieve the desired state of ketosis. “It’s impossible to pinpoint the exact time of the transition from glucose to ketones,” says Clarkson. “It depends on many factors: genetics, health, lifestyle, how much you ate before and how much energy you expended.” A person who eats a lot of carbohydrates almost never goes into ketosis because their body has a reserve of polysaccharides. However, for those who eat little sugar and exercise regularly, it can happen quite quickly. The low carbohydrate keto diet works in a similar way by adhering to it to reduce blood sugar levels.
“I would not resort to intermittent fasting for the purpose of burning fat, and those who do need to think about the health consequences,” Clarkson believes. “To be hungry, you first have to learn how to control the feeling of hunger,” she explains. The feeling of hunger occurs when the hormone ghrelin, produced in the stomach, begins to stimulate the synthesis of two other hormones in the hypothalamus: neuropeptide Y and agouti-related peptide (AgRP). These substances cause hunger, while others, called “satiety hormones,” suppress it. Among the latter is leptin, which is produced by fat cells and inhibits the synthesis of ghrelin. It sends a signal to the body as if to say, “There’s still plenty of fat around. Ghrelin is sometimes called the fast hunger response because it is produced immediately when the stomach is empty and the pressure on its walls decreases. To some extent, this can be counteracted by drinking water. Leptin, on the other hand, works over a longer period of time. “The production of hunger hormones is regulated by many factors, including individual genetics,” says Clarkson. “But the main role is played by nerve endings in the stomach and digestive tract. If the stomach is not stretched, the body thinks it is hungry.” She added that abundant hydration can help with this feeling at first, until the body adjusts to a smaller amount of food: “The first few weeks will be difficult, but then you will get used to it.
For most people, ketosis begins within 12-24 hours of a meal. So if you ate dinner between 18:00 and 20:30, your satiety will pass between 21:00 and 23:30, and ketosis and autophagy will start between 06:00 and 08:30 the next morning. “But most people reach for something edible at the first sign of hunger,” Clarkson continues. “A sandwich, a sweet drink, or a can of beer will satisfy you for about three hours. And if you have a snack around 9:30-10:00 p.m., it will last until 1:00 a.m. or even 3:00 a.m.” This means that ketosis will not occur at all – a person will have breakfast first. “If you have made a conscious decision to eat dinner an hour earlier and then not touch food afterwards, you have a chance to be in a state of ketosis by morning – unlike those who not only snack after a high-carbohydrate dinner, but also wake up at six in the morning,” says Clarkson. The expert advises getting used to an early dinner starting Sunday night, then having breakfast an hour later on Monday, and gradually adding one or two days a week.
With a thoughtful approach, intermittent fasting can sometimes help the body repair itself. Autophagy declines with age, and artificially stimulating it is not harmful. However, it should not be relied upon heavily for weight loss. It is important to remember that fasting is not a substitute for a balanced diet. I’m sorry, but you have not provided the Russian text to be translated. Please provide the text to be translated and I’ll be happy to help you.
The content of this article is for general information only and is not a substitute for professional medical advice and assistance. The BBC recommends that anyone interested in intermittent fasting consult a specialist first to avoid possible adverse effects. BBC is not responsible for any diagnoses or actions taken as a result of reading this article, nor for the content of any other web sites linked to it, and does not participate in the commercial promotion of any products or services recommended on those web sites. If you are concerned about your health or the health of a loved one, always consult your physician.