Fasting - Health Benefits

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Fasting - Health Benefits
Fasting - Health Benefits

Video: Fasting - Health Benefits

Video: Fasting - Health Benefits
Video: Intermittent Fasting May Have Health Benefits Beyond Weight Loss | TODAY 2023, December

Fasting & Detox

Fasting was already part of many religions and medicine (therapeutic fasting) thousands of years ago. Even today, many people turn to voluntary renunciation. The conscious restriction often represents an attractive counterpoint to excess and is intended to facilitate the reflection on the essentials. Often, health motives are also in the foreground. Last but not least, fasting is often the reason for a desired weight reduction. As diverse as the individual motives for voluntary renunciation are, as different are the designs and the types of fasting. However, the theses of “acidification of the body”, “purification” and “detox” do not stand up to any scientific examination. The expectations of fasting are high - but what can one really hope for from fasting from a health point of view?


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  • ">What does fasting mean?


  • What happens in the body during fasting?
  • Should a fast be carried out under medical supervision?
  • Can fasting have positive effects on health?
  • What types of fast are there?
  • Can Fasting Help Weight Loss?


What does fasting mean?

In contrast to starvation, fasting means voluntarily abstaining from food for a limited, usually self-defined period of time. As part of the fasting cure, fasters often deal intensively with their own body, their health and diet. Fasting is not suitable for long-term weight loss. However, it can make it easier to get started on a permanent, healthy diet.

What happens in the body during fasting?

Fasting puts the body in an exceptional situation. Since no or insufficient nutrients are absorbed, the body has to fall back on energy reserves. The body's carbohydrate stores (glycogen) in the liver and muscles are used up around twelve hours after the last food intake. There is a change in metabolism (starvation metabolism). The body soon begins to break down its own protein, especially muscle tissue, when hungry. This protein is converted into glucose (sugar) in the liver. This process is important because the red blood cells (erythrocytes), the central nervous system, the brain and the kidney medulla are particularly dependent on glucose and need to be “emergency supplied”.

In emergency situations, the body simultaneously creates so-called ketones from free fatty acids (these are released when body fat is broken down). The free fatty acids accumulate as a by-product of fat burning after a longer episode of hunger. The ketones can be used as an energy source by the brain and the central nervous system. After about five days, most of the energy required comes from fatty acids and ketone bodies. The ketone bodies can lead to the typical "acetone smell" of the breath during fasting. In addition, too high a concentration of ketone bodies can lead to an increase in uric acid concentration (gout attack) and metabolic imbalances.

Fasting also causes hormonal changes in the body, such as a drop in thyroid hormones. This, as well as the increased breakdown of muscle mass, lead to a reduction in the basal metabolic rate. The lower the basal metabolic rate, the fewer calories the body needs at rest. The lower basal metabolic rate is also responsible for the so-called yo-yo effect after weight loss diets.

Note Weight loss, which is particularly noticeable at the beginning of a fast, is due to the loss of fluid and the breakdown of muscle mass.

Should a fast be carried out under medical supervision?

A fasting cure should only be carried out under medical supervision, as it can lead to health risks (e.g. circulatory problems, cardiac arrhythmias). In order to clarify whether there are any medical objections, a doctor should be contacted before the fasting cure. During fasting it is important to observe certain parameters (e.g. blood pressure, heart rate, urine) in order to be able to counteract impending complications in good time.

Possible consequences and dangers are:

  • insufficient supply of nutrients (including proteins, fatty acids),
  • Breakdown of endogenous proteins (mainly from muscles),
  • hormonal changes (e.g. thyroid hormones),
  • Reduction of the basal metabolic rate (calorie requirement at rest),
  • Imbalance in electrolyte balance (minerals),
  • Increase in free fatty acids and ketone bodies,
  • increased uric acid concentration (risk of gout attack),
  • Visual disturbances, increased feeling of cold,
  • Circulatory disorders, dizziness, vomiting, hair loss,
  • reduced performance and difficulty concentrating,
  • Cardiac arrhythmias.

Danger! Zero fasting, in which only energy-free drinks such as water, mineral water and unsweetened tea are consumed, is not recommended for certain groups of people. These include children and adolescents, pregnant women, breastfeeding women, the elderly and people with certain diseases (e.g. type 1 diabetes, liver and kidney diseases and eating disorders). Caution is particularly advisable with fasting aids (e.g. enemas, laxatives or drainage agents, Epsom salts).

Can fasting have positive effects on health?

With good preparation, fasting can have a positive effect on the body. A sufficient supply of nutrients and personal wellbeing should always be in the foreground.

Fasting can be used as an introduction to a sustainable change in diet. After the food abstinence, the sweet and salty taste as well as the internal signals for hunger, satiety and appetite are perceived more consciously. Weight loss and the mood-enhancing effects of fasting can increase motivation for a health-promoting lifestyle.

What types of fast are there?

There are many different methods of fasting, which differ in their composition and frequency of meals. These include:

Schroth cure

Moist wraps and restricted food intake (low in salt, low in fat and protein, high in carbohydrates, for example with dry bread rolls, semolina, rice, oats and cooked fruit and vegetables) should "detoxify" the body. In the Schroth cure, three dry days alternate with two large and two small drinking days. The dry day consists of a glass of orange juice. One liter of liquid may be drunk on the small drinking days and two liters of liquid may be drunk on the large drinking days. According to the original instructions, the liquid is taken in the form of a white country wine. Today it is often exchanged for fruit and vegetable juices.

The assumption that toxins and waste products are sucked into the blood from the tissue on dry days and flushed out through fluid intake on drinking days cannot be scientifically proven.

Intermittent fasting

Intermittent fasting, also called intermittent fasting or periodic fasting, can be implemented in different ways. For example, with “5: 2” fasting, people eat and drink “normally” on five consecutive days and fast on the following two days, when hardly any calories are absorbed. Another variant is "Alternate Day Fasting". Fasting days and days with normal food intake are alternated here.

Most concepts of intermittent fasting contain no or only very vague recommendations for food selection. Therefore, intermittent fasting alone usually cannot change or balance unfavorable eating habits.

Nevertheless, the data so far indicate that intermittent fasting can have positive effects on health and weight loss. For example, the InterFAST study by the Karl Franzens University of Graz and the Medical University of Graz examined the effects of so-called "Alternate Day Fasting". The result showed that after four weeks, in addition to weight loss, there was also a positive influence on, for example, the cholesterol level, blood pressure, belly fat and inflammation parameters. The Interfast 2 study is currently investigating the effects of intermittent fasting in patients with type 2 diabetes mellitus who already require insulin therapy.

However, there is still a lack of studies with long-term data and consequences (longer than a year) and studies with sufficiently large study populations.

In addition, intermittent fasting is intended as permanent nutrition compared to other forms of diet. It remains to be seen whether the compliance of those interested is greater here than with other forms of diet. The scientific team behind at Danube University Krems (Cochrane Austria) offers more information on the subject.

Detox diets

Detox diets (also called detox diets) are pure juice diets. The idea behind these cures is that even healthy people should occasionally rid their body of toxins or "waste products" that accumulate in the body. After a bowel movement, water, herbal tea, and fruit and vegetable juices are usually drunk for days. Following this, a high-fiber diet with vegetables, fruit and raw vegetable juices is recommended. According to the supporters of detox cures, the body breaks down substances such as alcohol, medication and environmental toxins.

There are currently no studies that have shown any health benefits from detox cures. Proving an effect is also made more difficult because the term “detox” is not clearly defined.

In addition, it has not been proven whether there are "waste products" and whether they accumulate in the body, nor whether possible pollutants can be removed by detox cures. The term "slag" comes mainly from the metal and heavy industry. The scientific team behind at Danube University Krems (Cochrane Austria) offers more information on the topic.

Note The body has a tight detoxification system that immediately discards substances that arise in the metabolism or that are absorbed from the outside, such as medication and other harmful substances. The most important detoxification organs are the liver, kidneys and intestines, as well as skin and lungs. The body also reacts immediately to any shifts in the acid-base balance, for example by adjusting the respiratory rate or the urine concentration.

Base fasting

This fasting trend is based on the assumption that acidic or acidic foods (e.g. meat and sweets) lead to over-acidification in the body, which, among other things, is said to promote chronic inflammation. Therefore, only those foods that are basic or base-forming are allowed. These include fruit, vegetables, potatoes and herbs. In addition to the diet, alkaline-promoting substances, mostly in the form of food supplements, are taken.

There is no scientific support (evidence) for alkaline fasting, as the scientific team from Medizin-Transparent sheds light on. Because the body regulates the acid-base balance itself and balances the proportion of acids and bases in the blood. Acid and alkaline substances produced during digestion are excreted with the urine, for example. In contrast to blood, where the pH value is kept relatively constant by the body, the acid or base content of the urine can fluctuate greatly. However, acidic urine says nothing about the ph value of the blood. Above all, this is not related to a possible "acidification" of the body, as is claimed by representatives of the alkaline diet. In addition: Bases can also have a caustic effect.

Note In some organs, an acidic environment is even necessary. For example, digestion would only function poorly without the strongly acidic stomach acid. In addition, it ensures that potentially dangerous germs are killed. The surface of the skin also has an acidic environment in order to ward off pathogens

Can Fasting Help Weight Loss?

In order to sustainably normalize body weight and avoid the risk of the yo-yo effect, nutrition companies recommend a long-term diet change in combination with sufficient exercise. The diet should be based on the Austrian food pyramid, which is an aid to the practical implementation of a balanced diet. A healthy lifestyle also includes getting enough exercise. We recommend at least 2.5 hours per week for adults with moderate intensity (e.g. slow cycling) or 75 minutes of intense intensity (e.g. running).

If a fasting cure serves as an introduction to a health-oriented, long-term change in diet and lifestyle, it can definitely be viewed as positive.