Fasting Methods Compared: Buchinger, F.X. Mayr, Intermittent, Juice Fasting

The Essentials at a Glance

• Fasting methods do not differ on a safety question but in process and emphasis: Buchinger and F.X. Mayr are both serious, well-established approaches.
• Buchinger therapeutic fasting is compact fasting over several days, carried by tea, water, mild vegetable broth and freshly pressed juices.
• The F.X. Mayr method focuses on rest for the digestive system, a mild, easily digestible diet and chewing training – thorough, mindful chewing.
• Intermittent fasting, typically in a 16/8 rhythm, is not a replacement for compact fasting but its translation into everyday life.
• What they all share is the goal of autophagy, cellular recycling – at Naturhotel Tannerhof, the Buchinger method has been practised under medical supervision for more than 70 years.

The fasting methods

Anyone who looks into fasting quickly comes across several names: Buchinger therapeutic fasting, the F.X. Mayr method, intermittent fasting, juice fasting. At first glance they look like competing schools, with a choice to be made between them. In fact they describe different paths to a similar goal. The difference lies in process and emphasis, not in a hierarchy of credibility.

This overview situates the main fasting methods clearly – what defines each one, how they differ in process and what they share. At Naturhotel Tannerhof the Buchinger method has been practised across more than three generations of doctors, always under medical guidance; anyone who wants to look at the house's method in detail will find it on the Buchinger method page. The comparison here stays independent of that: it describes the methods rather than ranking them.

One point applies across the board: fasting is more than a diet. It is a therapeutic method, a cleansing on many levels and an encounter with oneself. Weight loss may be a side effect; the core lies elsewhere – in the shared goal described further down.

Buchinger therapeutic fasting

Buchinger therapeutic fasting is the deliberate, time-limited renunciation of solid food and stimulants. It is the best-known form of therapeutic fasting in German-speaking countries and goes back to the physician Otto Buchinger (1878–1971), who developed fasting from folk medicine into a medically guided method.

What sets it apart is its structure as compact fasting over several days, carried by liquids. Unlike a pure zero-calorie diet, the body is not left entirely without intake: a rhythm of mild liquids carries the day and gives metabolism some substance. Herbal tea in the morning, a mild vegetable broth at midday, a freshly pressed fruit or vegetable juice in the evening, plus generous fluids throughout the day. This structure keeps the person mobile rather than grounding them.

The focus is on the depth of the metabolic shift. The longer one fasts, the deeper the effects reach – one reason Buchinger fasting is typically planned for five days or more. How well tolerated this is was shown by a large observational study by Wilhelmi de Toledo and colleagues in 2019, published in PLOS One: 1,422 people were monitored across fasting periods of four to twenty-one days following the Buchinger method, with no severe or lasting adverse effects and a clear rise in physical and emotional well-being.

The F.X. Mayr method

The F.X. Mayr method goes back to the Austrian physician Franz Xaver Mayr and is also a serious, well-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 settle.

At its heart is chewing training. Every bite is chewed very thoroughly, slowly and mindfully – an element that also plays a role in breaking the Buchinger fast at the Tannerhof, with the apple, each bite chewed thirty to forty times. The F.X. Mayr method makes this thorough chewing the central focus and combines it with the so-called mild eliminating diet: easily digestible, gentle foods that calm digestion.

The difference from Buchinger therefore lies in process and emphasis, not in indications and not in a safety question. Where Buchinger as compact fasting largely forgoes solid food, F.X. Mayr works with mild, solid restorative food and trained chewing. Both paths aim at the same cleansing and renewal.

Intermittent fasting

Intermittent fasting is the form of fasting that fits most easily into daily 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 in which to eat. Other rhythms use whole fasting days per week.

The principle has been well documented scientifically in the widely 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 meal breaks are long enough, metabolism shifts from using glucose to using ketone bodies from fat metabolism. This is the same shift that takes hold during multi-day fasting – in intermittent fasting it is triggered regularly on a smaller scale.

The framing matters: intermittent fasting is not a replacement for Buchinger compact fasting. It is the form that translates the benefits of a fasting week into ordinary weeks and holds them in daily life. At the Tannerhof, intermittent fasting – for instance as Schlanke Tanne Intervall – is therefore the recommended everyday integration after a fasting week, not its alternative.

Juice fasting

Juice fasting describes a form of fasting in which freshly pressed fruit and vegetable juices carry the day, supplemented by water and unsweetened teas. The juices supply vitamins, minerals and some energy while solid food is set aside. The process resembles Buchinger fasting, which also uses freshly pressed juices – although in classical Buchinger therapeutic fasting the juices are one element alongside tea, water and mild vegetable broth, not the sole basis.

As a stand-alone method, the focus of juice fasting lies on liquids as the carrier and on light, plant-based intake. It is low-threshold and works well over a few days. As with any form of fasting: which variant suits the individual and how long it makes sense belongs, for health questions, in a medical consultation.

The fasting methods compared

The following overview sets the four fasting methods side by side by process and focus. The shared goal – cleansing, renewal, autophagy – belongs to all four and therefore has its own column.

The table reveals the pattern: the differences are differences of how, not of where. Compact or integrated, with juices or with restorative food, over days or within a day's rhythm – the fasting methods place different accents on the same underlying idea.

The shared goal: autophagy

However different the processes are, related processes run in the body. Two levels need to be distinguished, which are often conflated.

The first is fat metabolism. As the readily available carbohydrate stores decline, metabolism shifts from glucose to fatty acids and ketone bodies. This is the energetic side – the body increasingly draws its energy from its own reserves. The second level is autophagy: the body's own recycling and cleansing processes at the cellular level, in which cell components are broken down, reused and reordered. How fundamental this mechanism is was made clear by the 2016 Nobel Prize in Physiology or Medicine, awarded to Yoshinori Ohsumi for the discovery of the mechanisms of autophagy. Put more vividly: cleaning is happening everywhere – cellularly, vascularly, in connective tissue, in the gut, in the brain, in the liver and the kidneys.

These two processes are the connective element across the fasting methods. Whether the switch into ketosis takes deep hold over several days or is triggered regularly in shorter intervals – the goal of cleansing and renewal is the same. The scientific grounding for this is broadly documented: the guidelines on fasting therapy come from the Ärztegesellschaft Heilfasten und Ernährung (ÄGHE), originally published in 2002 and updated in 2013; further studies on fasting therapy are available through the ÄGHE. They place its use under expert guidance in conditions including rheumatic diseases, high blood pressure, metabolic syndrome, allergies, autoimmune diseases, migraine, type II diabetes mellitus and depression.

Which method for what

Rather than a ranking, it is worth looking at what each method delivers at its core:

• Buchinger therapeutic fasting suits a compact, deep break over several days – a deliberate time-out in which the metabolic shift gets room.
• F.X. Mayr places its focus on digestion and chewing training through a mild, restorative diet.
• Intermittent fasting carries the fasting effect into daily life, as a lasting form for ordinary weeks.
• Juice fasting is a low-threshold, liquid-led entry over a few days.

At Naturhotel Tannerhof the Buchinger method is practised – it is the house's method, under medical supervision for more than 70 years and anchored in the DNA of the house. Intermittent fasting follows on, to translate the effect of a fasting week into everyday life. Which form suits the individual case does not belong in a general formula; for health questions it belongs in conversation with the medical team.

Fasting at the Tannerhof: Buchinger, medically supervised

At the Tannerhof fasting is not an off-the-shelf programme but a familiar practice. Medical supervision is not strictly required for fasting in general, but it is sensible – at the Tannerhof it is always part of the picture, because the medical experience of the house belongs together with the fasting process. The doctors at the Tannerhof are experts in fasting.

The core is the medical intake consultation on the first fasting day, the day after arrival. It is holistic in scope: case history, physical examination including bioimpedance analysis to measure body composition, and a medication review, alongside the questions that mean the person – why fast, which goals at the Tannerhof beyond fasting, what fasting experience already exists. The length of stay booked before arrival can be adjusted together with the medical team from this consultation onwards, often extended. The stay closes with a final consultation in which what has changed is reviewed and the diet for everyday life is discussed – often Schlanke Tanne Low Carb, the house's own low-carb form, or intermittent fasting as the everyday form.

The accompanying therapy programme is intentionally broad, because fasting is more than a dietary shift for a few days. Medical applications include bioimpedance analysis, IHHT altitude training depending on the programme and, when medically appropriate, ozone autohemotherapy. Added to these are compresses and wraps such as the liver-supporting hay flower wrap, aroma wraps and moor and warm packs, baths and pourings such as the Kneipp alternating pour and magnesium-rich detox baths, massages such as the fasting massage, the detox massage with King's Oil and the acidosis massage, lymphatic drainage and foot reflexology, and breathing therapy. Movement remains measured: moderate base endurance training and moderate strength training, yoga, Feldenkrais and tai chi, complemented by the full facilities on site with the Tannerhof Spa and the BadeHarpfe with its 25-metre outdoor natural pool, which opens the view between the Wendelstein and Sonnwendjoch. For the mental side, psychotherapeutic coaching, nature coaching, business and communication coaching as well as art therapy provide support.

All of this takes place in Bayrischzell, between alpine meadow, mountain stream and clear, pure mountain air. Setting and medical supervision carry equal weight – fasting in a moving landscape is much more intense. My hideaway in the mountains takes on a particular depth in fasting. Anyone who wants to look at the specific framework and book online will find it in the Body Detox programme, embedded in the Therapeutic Fasting and Schlanke Tanne hub.

Discover fasting at the Tannerhof

Naturhotel Tannerhof has offered Buchinger therapeutic fasting for more than 70 years: medically supervised, with fasting experience across every department, embedded in Bayrischzell between alpine meadow, mountain stream and the view to the Wendelstein. Anyone who wants to look at the specific framework and book online will find it in the Body Detox programme and on the page about the Buchinger method.