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Therapeutic fasting, water fasting, intermittent fasting – there are many ways of abstaining from food or severely restricting it. Fasting is more popular than ever, but is it healthy?

In this article, Silvia Bürkle explains on a scientific basis which beneficial metabolic processes can be triggered in the body while fasting and to what extent fasting can be combined with the Metabolic Balance program.

More energy through fasting

Therapeutic fasting, water fasting, intermittent fasting – there are many ways of abstaining from food or severely restricting it. Fasting is more popular than ever, but is it healthy?

Fasting differs in many ways from renouncing food or from a starvation diet. While fasting, some sensible changes take place in the metabolism. This allows our body to make the best use of its nutrient reservoirs as a source of energy.

Throughout the history of human evolution, breaks from food and times of shortage were not uncommon. During these times, the body mobilized its reserves and thus ensured its survival.

Today, fasting in spring or during the fasting period between Ash Wednesday and Easter is no longer a way of overcoming times of scarcity, but a positive experience of abstinence in our affluent society.

Fasting and metabolism

While fasting, the energy cycle of eating, i.e. nutrition from the outside, switches to the energy cycle of fasting, i.e. nutrition from the inside. The signal for the start of fasting and the metabolic switch is the emptying of the gastrointestinal tract with Epsom salts or by means of an enema. Emptying the bowel causes blood sugar levels to drop, insulin levels to decrease and glucagon and adrenaline to be released. These hormones cause more fat to be released from the adipose tissue and make it easier for fatty acids to be absorbed into the muscle cells. The muscle cells can thus cover a large part of their energy requirements, but the heart and kidney metabolisms also use fat as fuel. In addition, carbohydrate reservoirs (glycogen) are released from liver and muscle cells. These reservoirs mainly serve as a source of energy for the brain, nerve cells and red blood cells. However, carbohydrate reservoirs are limited and are already significantly reduced after the first few days of fasting.

The fatty acids released from the fat reserves cannot easily be converted into glucose. However, in order to ensure that all organs are supplied with sufficient energy during a fasting period lasting several days or even several weeks, the body switches to gluconeogenesis. This stimulates the formation of new glucose. This mainly takes place from the building blocks of proteins, the amino acids, lactate and pyruvate. Gluconeogenesis mainly takes place in the liver at the beginning of fasting. The newly formed glucose is now primarily available to the nerve cells.

Using fatty acids – ketone bodies

In addition to gluconeogenesis, the  fasting metabolism is also characterized by ketogenesis, i.e. the conversion of fatty acids into ketone bodies. As more fatty acids are available than are used by the muscles, the fatty acids are converted into ketone bodies. The more the glycogen reserves are reduced, the more these are the “replacement energy source” for the nerve cells and the like. It is also interesting to note that ketone bodies influence the immune system. Put simply, ketone bodies prevent immune cells from making contact with each other. A certain protein complex (inflammasome) is located on the surface of the immune cells, which has the task of activating other players in the immune defense. If ketone bodies now block these protein complexes, an outbreak of inflammation can be prevented or an inflammatory process can be attenuated.

Ketone bodies also have the pleasant side effect of reducing feelings of hunger.

More well-being through exercise

Anyone who occasionally undergoes a fasting week gives their body a breather. In a profound physical and mental process of cleansing and reorientation, everything that burdens and makes you ill is disposed of, just like in a garbage incineration plant. Fasting relieves the entire organism, especially the digestive organs and the intestines.

Physical exercise and sport, adapted to your personal fitness level during fasting, can also support fasting. Exercise and relaxation also strengthen the immune system and improve regeneration and body awareness. Being active also keeps the heart and circulation going and strengthens the muscles.

Fasting has been shown to reduce the inflammatory parameters TNF-alpha and interleukin-6, which stimulate inflammatory processes.

It also promotes the excretion of acidic metabolic products via the lungs. During prolonged abstinence from food, the Human Growth Hormone (HGH), is also produced, which supports fat loss and at the same time promotes muscle formation by boosting protein build-up. Weight loss during the fasting cure is a pleasant side effect.


Changes don’t happen overnight, but are a longer process. You won’t be able to get rid of all your “bad” eating habits overnight – and you don’t have to. The important thing is simply to realize that fasting can be the basis for better health and well-being. Fasting offers the ideal starting point for a change in diet, for example for the Metabolic Balance nutrition concept. Longer breaks between meals are an important behavioral change in Metabolic Balance. During these longer breaks, however, the body does not slow down the metabolism and does not reduce muscle mass. This is because our metabolism works in phases. The natural alternation between building up and breaking down metabolic processes, the so-called anabolic and catabolic phase, is much better for our body and is much healthier than a constant build-up and stimulus to growth.


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