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Medical & Therapeutic Fasts

by | Jun 10, 2020 | FASTING METHODS | 0 comments

The Big Idea

Our society is held captive by the concept that better results come from more action. We have to take more pills to be healthy; we have to do more exercise (cardio, cardio, cardio!) for fat loss. The idea that you can achieve far greater health while technically doing nothing is incomprehensible to most people. But that’s exactly what medical/therapeutic fasting is – eating nothing. And it’s regarded as one of the safest and most effective treatment methods for literally dozens of diseases.

Therapeutic fasting has been used since ancient Greek physicians, such as Hippocrates and Galen, and it continues to be used by the modern medical establishment for the treatment of diseases ranging from obesity to cancer and even diabetes. Fasting is generally recognized as being safe by doctors, and has been used effectively for durations as short as 14 hours all the way up to a year. 

What it is

Though there are different medical/therapeutic fasting methods, they all share the concept of abstaining from or restricting food for the treatment of medical conditions. Longer fasts are often performed under the guidance of a doctor or fasting practitioner who monitors vitals and progress. Medical/therapeutic fasts can include

  • prolonged water fasts
  • fasting mimicking diets
  • and even time-restricted eating

But therapeutic fasts aren’t solely about not eating food. Many of the benefits come in the days after a patient breaks his or her prolonged fast, when stem cell counts often double, and the body is able to rejuvenate after its cleansing period.

Scientists have observed that fasting shrinks the body’s organs and tissues. This happens when organelles called phagophores dissolve and recycle old and useless parts of a cell – a process known as autophagy. Once the body’s damaged cells have been cleaned out and food is reintroduced, organs and tissues regain their lost volume with healthy and youthful cells, and health is restored.


Potentially reverses autoimmune diseases

Research on mice has shown that therapeutic fasting reduces the severity of autoimmune symptoms, with a full 20% of the experimental group exhibiting a full remission of symptoms. Research on humans show that fasting can be beneficial for Rheumatoid Arthritis and other autoimmune diseases. Scientists think this effect is due to an increase in immune system stem cells, and also a reduction in inflammation.

Increases effectiveness of cancer treatment

During periods of food shortage, cells favor repair and maintenance over growth. Scientists think this could have been nature’s way of improving our odds of survival. This ‘repair and maintenance’ effect of fasting has been proven to increase the resilience of healthy cells in chemotherapy treatment. Studies also show that fasting may increase the effectiveness of chemotherapy treatment.

Diabetes management

Therapeutic fasting is demonstrated to reduce all markers of diabetes and metabolic syndrome, including blood glucose levels, insulin levels, cholesterol, and weight. This finding has been replicated in many human and animal studies, and results have come from fasting as little as 14 hours per day. Scientists have reported improved diabetes symptoms independent of weight loss, too.

Weight loss

Weight loss is one of the most common applications for medical/therapeutic fasting. Whereas calorie restriction tends to diminish metabolism, fasting (and fasting mimicking diets) are proven to burn fat without negatively impacting metabolic rate. This frequently leads to long-term weight loss and diminished weight-loss rebounds


Compared to bariatric surgery – stomach stapling, – prescriptions, and other medical interventions, therapeutic fasting is very inexpensive. Though there are treatment centers where you can spend thousands of dollars for a luxury experience, standard fasts typically cost nothing. (And you’re even saving money on food and drinks!)


While there certainly are risks to medical/therapeutic fasts, these are nothing to be concerned about if you prepare for the fast and consult your physician. Typical risks include the following:

  • dehydration
  • electrolyte imbalance
  • hypovolemia
  • fatigue
  • dizziness
  • feelings of fainting
  • headache
  • and hypertension.

People commonly experience irritability and low-energy during prolonged fasts because the body is transitioning from using carb-containing foods for energy to just your body fat. That said, some therapeutic fasts can be as little as 14 hours in duration, with no risk at all.

How to Do it

Therapeutic fasts are best performed under the guidance of a physician or trained fasting practitioner. You can either enter a fasting treatment center, where your fasting itinerary is made for you. Or you can perform the fast at home.

Time-restricted eating

Time-restricted eating (TRE) is a therapeutic fasting method shown to improve diabetes, weight, and cardiovascular health. It’s done by limiting your eating to the daytime and by fitting all your meals within an 8-12 hour window. Typical TRE fasts last from after dinner to sometime in the morning or afternoon. For example, you’d eat your first meal at 10:00 am, the stop eating at 6:00 pm.

Water fasts

To perform a therapeutic water fast, you’ll only be allowed to consume water. This typically lasts from 1-5 days, and should not be undertaken without careful preparation and/or supervision. You should follow these precautions:

  • Spend at least a week practicing shorter, daily fasts of 12-16 hours before your fast.
  • Avoid processed foods and eat smaller, lighter meals in the days before your fast – soups, salads, fruits and vegetables, and juices. This prepares your system for a smooth transition to a full fast.
  • Make sure to drink ample amounts on your fasting days. (The body gets 20-30% of its water from food, so you’ll want to make up for that in liquid water.)
  • Do light exercise such as walking or hiking, and avoid heavy lifting or intense exercise like running or crossfit.
  • Replenish electrolytes with a multimineral supplement, and add a pinch of sea salt to your water in the mornings.
  • End your fast if you feel sick or unwell. (Mild symptoms such as headaches or fatigue should be expected, but not sickness.
  • Break your fast with light foods such as rice, bread, soup, or fresh-squeezed fruit and vegetable juice. Wait till the next day to introduce heavier foods like meat.

Fasting Mimicking Diet (FMD)

FMD was invented for cancer patients as a way to access the benefits of prolonged fasting without the irritability, hunger, and stress that can accompany standard fasting. The diet has been patented and is sold in packaged meal kits that contain specific calories, macronutrients, and instructions for the FMD.

Key Experts:

Dr. Françoise Wilhelmi de Toledo

Dr. Françoise Wilhelmi de Toledo

Dr. Françoise Wilhelmi de Toledo is the founder of the Medical Association for Fasting and Nutrition (ÄGHE) and serves as Managing Director of the family-owned company Buchinger Wilhelmi. A passionate educator and advocate for fasting, her life’s work has been devoted to the study and application of therapeutic application fasting and integrative medicine. With her husband, Raimund Wilhelmi, the grandson of Otto Buchinger, and their sons, they continue to play an active role in managing the family business and leading research including a 2019 study with 1,422 fasting subjects, that revealed that therapeutic fasting according to the Buchinger method is safe and therapeutically effective as well as boosting emotional and physical well-being.

“Humans have the ability to switch their metabolism to fat-reserve burning.”

Arnold Devries

Arnold Devries

Arnold Devries, author of ‘Therapeutic Fasting’, has inspired much of the enthusiasm for and research behind modern fasting. From his book:

“In terms of safety, fasting is without a doubt one of the best and most practical therapeutic agents. There are virtually no contradictions in fasting, in the sense that one part of the body is helped while another is harmed. In this respect it differs from so many other methods of treatment, which suppress one symptom, only to create others. Fasting helps the diseased organ in the same sense that it helps all other organs and tissues. Thus in securing a remedy for one disease, the body is made less liable to be afflicted by others. Health is restored by the safest and most effective means.”

Dr. Jason Fung

Dr. Jason Fung

Dr. Jason Fung is one of the most renowned fasting experts today. In an article, Dr. Fung noted that fasting is a universal habit of every being in nature. “Humans, like most animals,” he said, “do not eat when they become sick. For this reason, fasting has been called the ‘physician within’.” Dr. Fung said that everyone has practiced therapeutic fasting to some extent and that fasting should not be feared as a means for healing.

About The Author

Fast Forward Editors

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