The benefits and harms of therapeutic fasting: a fresh review from Tagesspiegel

2024 Author: Seth Attwood | [email protected]. Last modified: 2023-12-16 15:55

The first day of Great Lent is approaching. Fasting is found in almost all religions and cultures. Great healing power is attributed to temporary refusal of food. Some believe that in this way you can even extend your life. But doctors still argue about the benefits of fasting, and for some, fasting is even dangerous.

Certain fasting options are becoming more and more popular. Most often it has little to do with God, religion and spiritual self-flagellation. Refusal to eat should rather help to lose weight, fight all kinds of diseases or prevent them. Fasting is meant to make people in general healthier, to get in good shape, and, possibly, to prolong their life. But what is really known about the healing power of fasting?

What was the point of fasting in the old days?

Even in ancient Egypt, certain forms of starvation were in use, for example, refusal to eat fish during spawning in the Nile. The Christian fast, when for religious reasons meat cannot be eaten 40 days before Easter, according to anthropologists, was aimed at preserving livestock. At the end of winter, other food was often consumed, and the cattle had a reserve of calories. And he had to be protected.

For example, at this time, sows were born. This was a guarantee of protein food for a whole year if the peasant kept the piglets alive and fed them.

Yet these pragmatic reasons were definitely not the only ones. In almost every religion and every region of the world, there are certain forms of fasting.

At the very least, it can be assumed that fasting was a kind of measure to protect health, because people have accumulated knowledge about the beneficial effects of fasting for centuries and millennia.

Does "fasting" exist in nature?

In many species of animals, more or less prolonged periods of fasting occur constantly or periodically. Predators, for example, do not always manage to catch their prey when they are hungry.

And herbivores can have nutritional problems, for example, during a drought.

In animals hibernating in winter, periods of starvation are very long, this is genetically programmed in their behavioral model and in metabolism.

Periods of excess and lack of food followed each other in the lives of our ancestors. Those who survived the malnutrition better than others, and those who managed to get food, including from the reserves. It was they who multiplied and passed on their genes.

It is thanks to this evolutionary heritage that we, humans, are probably generally able to voluntarily and without harm to health today refuse food for a long time.

Modern fasting adherents describe how positive they are on days without food, how clear and clear their thoughts are, how active they are in the physical plane. It also makes evolutionary sense. It is during periods of fasting that the moment comes when you need to be best prepared to get food.

That is, when the star of Silicon Valley and the head of Twitter Jack Dorsey talks about his high feelings and clear thoughts on days with zero calories, he turns from a purely biochemical point of view into a hungry, ready for anything hunter in the savannah of our ancestors.

How to explain the current renaissance of fasting?

The reasons why more and more people are showing an interest in fasting are varied. A widespread excess of food, as well as the search for spiritual fulfillment of life, including without a specific religious doctrine, can play a role in refusing food - at least in countries where no one has to starve against their will.

Many people see fasting simply as a relatively unambiguous opportunity to lose weight by cutting out calories. It is likely that the numerous reports that temporarily avoiding food improves health and may even prolong life are becoming a determining factor.

What happens in the body during fasting?

After long hours without food, the body reconfigures its metabolism. It no longer uses glucose from carbohydrates, but converts fats in the liver into so-called ketones. They can supply energy to almost all cells in the body. In addition, molecules are released to protect cells, because lack of nutrition is stress.

An important factor is the lack of insulin production, since sugar does not enter the bloodstream through the intestines. In this state, the body is better able to destroy and recycle damaged cells. In addition, the restoration of the genetic material takes place. These defensive responses, also known as hormesis, are considered by many researchers to be the real cause of the health benefits of fasting.

What types of fasting are there?

Other variations can be added to the classic meat-free diet that has taken on a new dimension due to the spread of veganism and the climate movement. For example, multi-day or weekly fasting courses with virtually no calorie intake at all. These courses are run by specialized organizations and are usually accompanied by other treatments, such as laxatives and liver cleanses, and exercise.

But for this it is necessary to completely drop out of everyday life.

The religious options for fasting for Muslims include daily refusal of food and water during Ramadan. Here we are talking, in fact, about the very popular so-called intermittent fasting - the regular alternation of longer periods of time without food and periods when food is allowed.

Why is intermittent fasting so popular now?

There are many different options for intermittent fasting. Week 5: 2 implies that for five days a person eats as usual, and for two days he restricts himself very much in food. Another option is to completely stop eating one or more times a week. Thus, the fasting phases last about 36 hours, because the evening without dinner is followed by the night.

With the 16: 8 fasting system, the daily time window for food intake is limited to six to eight hours. Such programs are popular also because, unlike multi-day programs, they fit relatively easily into a normal daily routine.

Metabolism is best reconfigured when the last phase of fasting has ended not so long ago, and the body still has the necessary enzymes and activated genes.

The fact that intermittent fasting is promoted by many stars also plays a role. In recent years, there have been positive assessments of scientists. In a recently published study in the acclaimed New England Journal of Medicine, the authors conclude that intermittent fasting has several health benefits and may even prolong life.

What is the scientific evidence for health benefits?

Treat minor pain with fasting, not medicine - Hippocrates spoke about this. In the meantime, some doctors and epidemiologists attribute much more potential to fasting, believing that it can prevent or help cope with all serious diseases.

In fact, there are a number of animal studies showing that with intermittent fasting, subjects get less sick than their counterparts who eat as usual. Even tumors grow less actively or do not grow at all.

But experimental animals are not humans. However, scientific evidence based on human studies shows that overweight people lose weight with intermittent fasting. In addition, there are positive mental changes, and many blood counts are changing for the better, including insulin, blood lipids, cholesterol, and some substances that regulate inflammation. And some studies even show improved memory in older people.

What is the evidence for anti-aging and life-prolonging effects?

There has long been a debate about whether constant food restriction is beneficial to health and whether it prolongs life. For worms and mice, this is an indisputable fact.

As far as humans are concerned, impressive anecdotal evidence has emerged over the centuries. For example, you can name the records of a man named Luigi Cornaro, who lived in Padua in the 15th and 16th centuries. When he was 35 years old, doctors told him that he did not have long to live. After that, Cornaro began to adhere to a strict diet. He lived to be 100 or 102 years old and practically did not complain about his health.

This beautiful story becomes even more beautiful if you know that then it was allowed to consume three glasses of red wine daily. But neither in the days of Cornaro nor today is there any human research that offers validated conclusions.

Much of what people know about fasting fits well with the arguments of those who consider it a source of eternal youth. Fasting starts the processes during which toxins are removed from the body and damaged genes are restored. Molecules are formed that neutralize free radicals. Growth factors arise, which, in particular, ensure the growth of brain cells and strengthen the connections between them. There are many other good processes going on as well.

But will all this help to become a second Cornaro - or has Cornaro lived in good health for more than 100 years only thanks to good genes? Nobody knows that. Because the relevant research would be extremely costly and time-consuming as long as everything remains as it is. Otherwise, it would be necessary to monitor the health of a great number of study participants over the years - from adolescence to as late death as possible - and record in great detail what and how they eat, as well as take into account a host of other factors that may also be to play an important role.

Are there any other benefits?

Sociologists and psychologists see the positive aspect of fasting primarily in the fact that it develops a conscious approach to one's own body. It is also associated with problems such as gluttony and hunger in the modern world. Undoubtedly, avoiding whole meals and cooking can save time - unless you have to cook for the kids and other family members anyway.

What do the critics say?

For many years, traditional medical practitioners have considered food refusal to be fundamentally harmful. The arguments in favor of fasting were not too numerous and primarily boiled down to the following: those who do not eat for more than a couple of hours, the so-called catabolic metabolism is established. This means that the volume of the body is reduced, and not only fat, but also proteins from the muscles.

Prolonged catabolic metabolism leads to death, and it is typical for some serious diseases, in particular for advanced cancer. In the short term, there is also a release of toxins and a general weakening of the body. The aforementioned research results and data on metabolism and biochemistry caused many doctors to change their minds.

At the moment, the main criticism is directed at the fact that a significant amount of research is devoted only to weight, blood sugar and fat levels and some other indicators. Heidelberg-based diabetologist Peter Paul Nawroth calls these numbers "surrogate parameters" because they say nothing about whether people who regularly take off their fasting days actually feel better than those who do not starve themselves., and whether they really get sick less and suffer less from heart attacks, complications of diabetes and dementia.

About this, according to Navroth, "there is simply no data." Nutritionists are also inclined to believe that many questions still remain open. To this we can add that most of the studies related to various fasting options lasted only a few months. Therefore, there is no long-term information regarding the aforementioned "surrogate parameters".

From a purely practical point of view, the results of the studies carried out also indicate only that it is very difficult to conduct long-term observations of the nutrition of the subjects.

However, a recent study confirms that intermittent fasting is at least as beneficial as the so-called Mediterranean diet, which is high in vegetables, vegetable fats and fish.

Who should avoid fasting?

Among practically healthy people, there were no negative consequences of intermittent fasting. One of the most controversial fasting options is the "Brouss diet", which is recommended by some adherents of the so-called alternative cancer therapy. It lasts 42 days and does not involve any solid food intake. At the same time, the patient eats a small amount of vegetables every day, as a result of which, in theory, the cancer "dies of hunger." This is often the case - at least they say that tumors do shrink in size.

At the same time, however, the rest of the tissues of the patient's body also decrease in size, and the immune system is also weakened. And when nutrition is resumed, the growth of cancerous tumors begins again, which weakened patients can no longer resist.

True, in diabetics, according to research results, the indicators of blood tests significantly improve. However, they are the ones who need the most careful medical supervision due to possible complications.

It is fundamentally harmful for children to starve because they are in the process of growing and have limited reserves.

Culturally wrapped fasting practices seem to support these findings. For example, children under puberty do not need to go hungry during Ramadan. Only overly religious parents force their children to fast.

Fasting is strictly contraindicated for pregnant women. If they nevertheless decide to take this step, then they risk a child who threatens to be born prematurely and with congenital defects. For people with eating disorders, doctors also advise avoiding fasting because of the increased risks associated with it.