Fasting methods compared: Buchinger, F.X. Mayr, intermittent, juice fasting

The essentials at a glance

• Fasting methods do not differ in terms of safety, but rather in their process and focus: both Buchinger and F.X. Mayr are reputable and well-established.
• Buchinger therapeutic fasting is a compact fast lasting several days, supported by tea, water, mild vegetable broth, and freshly squeezed juices.
• The F.X. Mayr method focuses on resting the digestive system, a mild and easily digestible diet, and chewing training – thorough, conscious chewing.
• Intermittent fasting, such as the 16/8 rhythm, is not a substitute for compact fasting, but rather a way to translate it into everyday life.
• What they all have in common is the goal of autophagy, or cellular recycling – at the Naturhotel Tannerhof, we have been practicing medically supervised Buchinger fasting for over 70 years.

Types of fasting

Anyone looking into fasting will quickly encounter several names: Buchinger therapeutic fasting, the F.X. Mayr method, intermittent fasting, and juice fasting. At first glance, they seem like competing schools you have to choose between. In reality, they describe different paths to a similar goal. The difference lies in the process and the focus, not in a hierarchy of legitimacy.

This overview provides an objective classification of the most important fasting methods – what defines them, how they differ in practice, and what connects them. At the Naturhotel Tannerhof, we have been practicing Buchinger fasting for over three generations of doctors, always under medical supervision; those who would like to see the hotel's method in detail can find it on the page about the Buchinger method. The comparison here remains independent of this: it describes the methods, not a ranking of one against the other.

One point in advance that applies to all: fasting is more than a diet. It is a therapeutic method, a cleansing on many levels, and an encounter with oneself. Weight loss can be a side effect, but the core lies elsewhere – in the common goal, which is described in more detail below.

Buchinger therapeutic fasting

Buchinger therapeutic fasting is the conscious, time-limited abstinence from solid food and stimulants. It is the most well-known form of therapeutic fasting in German-speaking countries and dates back to the physician Otto Buchinger (1878–1971), who transformed fasting from folk medicine into a medically guided method.

What makes it special is the process as a compact fast over several days, supported by liquids. Unlike a pure water-only fast, the body is not left without any intake: a rhythm of mild liquids carries you through the day and provides the metabolism with some substance. A herbal tea in the morning, a mild vegetable broth at noon, a freshly squeezed fruit or vegetable juice in the evening, plus plenty of fluids throughout the day. This structure keeps the body active rather than shutting it down.

The focus is on the depth of the transformation. The longer you fast, the deeper the effects – one reason why Buchinger fasting is typically designed to last five days or more. A large observational study by Wilhelmi de Toledo and colleagues from 2019, published in PLOS One, demonstrates how well-tolerated this is: 1,422 people were monitored over fasting periods of four to twenty-one days using the Buchinger method, with no serious or lasting adverse effects and a significantly increased sense of physical and emotional well-being.

The F.X. Mayr method

The F.X. Mayr method dates back to the Austrian physician Franz Xaver Mayr and is also a reputable, established form of fasting. Its guiding principle is rest: the digestive tract is relieved through a mild, easily digestible diet so that the stomach and intestines can recover.

The focus is on chewing training. Every bite is chewed very thoroughly, slowly, and consciously—an element that also plays a role in the Buchinger breaking of the fast at Tannerhof, where every bite of an apple is chewed thirty to forty times. The F.X. Mayr method makes this thorough chewing the central pillar and combines it with the so-called mild elimination diet: easily digestible, gentle foods that soothe the digestive system.

The difference from Buchinger therefore lies in the process and the focus, not in the indications or any question of safety. While Buchinger, as a compact fast, largely avoids solid food, F.X. Mayr works with mild, solid, gentle food and trained chewing. Both paths aim for the same cleansing and renewal.

Intermittent Fasting

Intermittent fasting is the form of fasting that is easiest to integrate into everyday life. Instead of several consecutive fasting days, shorter eating and fasting windows alternate. The best-known variant is the 16/8 schedule: sixteen hours without food, eight hours during which you eat. Other rhythms work with entire fasting days per week.

The principle is well-documented scientifically in the frequently cited review by de Cabo and Mattson, published in 2019 in the New England Journal of Medicine. The authors describe so-called metabolic switching: when the breaks between meals are long enough, the metabolism switches from utilizing glucose to using ketone bodies from fat burning. It is precisely this switch that also takes effect during multi-day fasting—with intermittent fasting, it is triggered regularly on a smaller scale.

It is important to put this into perspective: intermittent fasting is not a substitute for compact fasting according to Buchinger. It is the way to translate the benefits of a fasting week into normal weeks and maintain them in everyday life. At Tannerhof, intermittent fasting—such as the "Schlanke Tanne" interval—is therefore the recommended daily integration after a fasting week, not an alternative to it.

Juice Fasting

Juice fasting refers to a form of fasting in which freshly pressed fruit and vegetable juices sustain you throughout the day, supplemented by water and unsweetened teas. The juices provide vitamins, minerals, and some energy, while solid food is avoided. The process is similar to Buchinger fasting, which also uses freshly pressed juices—however, in classic therapeutic fasting according to Buchinger, juices are one component alongside tea, water, and mild vegetable soup, not the sole foundation.

As an independent method, the focus of juice fasting is on liquid as the primary source and on light, plant-based intake. It is low-threshold and can easily be planned for a few days. As with any form of fasting, the question of which variant is suitable in an individual case and how long it makes sense should be clarified with a doctor if there are any health concerns.

Fasting Types in Direct Comparison

The following overview compares the four types of fasting in terms of process and focus. The common goal—cleansing, renewal, autophagy—is shared by all four and is therefore listed in its own column.

The table shows the pattern: the differences are in the how, not the where. Whether compact or integrated, with juices or with a gentle diet, over several days or on a daily rhythm – the different types of fasting emphasize different aspects of the same fundamental idea.

The common goal: autophagy

As different as the procedures may be, related processes occur within the body. Two levels must be distinguished here, which are often confused with one another.

The first level is fat burning. As readily available carbohydrate stores decrease, the metabolism switches from glucose to fatty acids and ketone bodies. This is the energetic side – the body increasingly derives its energy from its own reserves. The second level is autophagy: the body's own recycling and cleaning processes at the cellular level, where cell components are broken down, utilized, and reorganized. The fundamental nature of this mechanism is highlighted by the 2016 Nobel Prize in Physiology or Medicine, which was awarded to Yoshinori Ohsumi for his discovery of the mechanisms of autophagy. To put it more elegantly: everything is being cleaned – cellularly, vascularly, in the connective tissue, in the gut, in the brain, and in the liver and kidneys.

These two processes are the connecting element of all fasting types. Whether the switch to ketosis is profound over several days or triggered regularly through intervals – the goal of cleansing and renewal remains the same. The scientific basis for this is widely documented: the guidelines for fasting therapy come from the Ärztegesellschaft Heilfasten und Ernährung (ÄGHE), originally published in 2002 and updated in 2013; further studies on fasting therapy can be viewed at the ÄGHE. They classify its use under professional supervision for conditions including rheumatic diseases, high blood pressure, metabolic syndrome, allergies, autoimmune diseases, migraines, type II diabetes mellitus, and depression.

Which type of fasting for what purpose

Rather than a ranking, it is worth looking at what each method focuses on:

• Buchinger therapeutic fasting is suitable for a compact, deep break over several days – a conscious time-out that gives the transition room to unfold.
• F.X. Mayr focuses on digestion and mastication training through a mild, gentle diet.
• Intermittent fasting brings the effects of fasting into everyday life as a permanent form for normal weeks.
• Juice fasting is a low-threshold, liquid-based introduction lasting a few days.

At the Naturhotel Tannerhof, we practice Buchinger fasting – it is the house method, medically supervised for over 70 years and anchored in the DNA of the hotel. Intermittent fasting is added as a follow-up to translate the effects of a fasting week into everyday life. Which form is suitable in an individual case is not a matter for a general formula, but rather a conversation with the medical team regarding any health questions.

Fasting at the Tannerhof: Buchinger, medically supervised

At the Tannerhof, fasting is not an off-the-shelf cure, but a familiar practice. Medical supervision is not strictly mandatory for fasting in general, but it is sensible – at the Tannerhof, it is always included because the house's medical experience is inseparable from the fasting process. The doctors at the Tannerhof are experts in fasting.

The core is the initial medical consultation on the first day of fasting, i.e., the day after arrival. It is holistic in nature: it includes a medical history, a physical examination including bioelectrical impedance analysis to measure body composition, and a medication review, as well as questions about the individual – why they are fasting, what goals they have at the Tannerhof beyond fasting, and what previous fasting experience they have. The length of stay booked before arrival can be adjusted, and often extended, together with the medical team starting from this consultation. At the end, there is a final consultation to evaluate what has changed and to discuss nutrition for everyday life – often the "Schlanke Tanne Low Carb," our in-house low-carb diet, or intermittent fasting as a daily routine.

The accompanying therapeutic offerings are intentionally broad because fasting is more than just a dietary change for a few days. Medical applications include bioimpedance analysis, IHHT altitude training (depending on the program), and, where medically appropriate, ozone autohemotherapy. These are complemented by wraps and compresses, such as liver-supporting hay flower wraps, aroma wraps, as well as moor and warm packs, baths, and showers like Kneipp contrast showers and magnesium-rich detox baths. Massages include fasting massage, detox massage with royal oil, or acidosis massage, along with lymphatic drainage, foot reflexology, and respiratory therapy. Physical activity remains moderate: basic endurance and strength training, yoga, Feldenkrais, and Tai Chi, supplemented by the full facilities at the Tannerhof Spa and the BadeHarpfe with its 25-meter outdoor natural pool, offering views between the Wendelstein and Sonnwendjoch mountains. For the mental aspect, we provide psychotherapeutic coaching, nature coaching, business and communication coaching, and art therapy.

All of this takes place in Bayrischzell, amidst alpine meadows, mountain streams, and clear, pure mountain air. The environment and medical supervision are equally important – fasting in such a moving landscape is significantly more intense. My hideaway in the mountains gains a new depth during a fast. Those who wish to view the specific framework and book online can find it in the Body Detox program, embedded within the Therapeutic Fasting and Slim Fir hub.

Discover fasting at Tannerhof

The nature hotel Tannerhof has been offering Buchinger therapeutic fasting for over 70 years: medically supervised, with experienced staff in all departments, and nestled in Bayrischzell, between alpine meadows, mountain streams, and views of the Wendelstein. Those who wish to view the specific framework and book online can find it in the Body Detox program and on the page dedicated to the Buchinger method.