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  • Writer's pictureMike Parker

Fasting helps your body heal through autophagy

If you pull a muscle you know you need to rest for the muscle to heal properly. If you catch the flu, you know you need to rest for your immune system to beat the virus quickly. You heal faster when your body can focus on healing. We all know this.

Yet most of us will go our entire lives eating three meals a day, never giving our bodies a rest from digesting, processing and storing all the nutrients it wants, whilst squeezing all that decomposing food through metres of digestive tract before ejecting it at the far end. Even while we are sleeping our digestive systems are hard at work.

Every system needs downtime for maintenance. There is only so much that can be done while the system is running. We wouldn't expect our cars to run continuously without servicing, so why do we expect our bodies to?


The only way to allow your body to rest completely is to stop eating. Many of the world's religions incorporate periods of fasting, or Intermittent Fasting. At the time of writing, followers of Islam are observing Ramadan, where they do no eat or drink anything during daylight hours. Earlier in the year Christians were observing Lent, where Jesus is said to have fasted for 40 days and 40 nights. People have been incorporating periods of fasting in their lives for thousands of years for spiritual reasons.

Fasting has attracted a lot of attention in recent years for the health benefits and fat loss. In the UK, Dr Michael Mosley published the 5:2 fast diet, after researching the benefits of intermittent fasting and trying it out for himself as part of a BBC documentary. His form of intermittent fasting was to fast on two non-consecutive days each week, eating only a quarter of his normal intake on fasting days. The effect on him of this simple dietary change was to lose 9 kg over 12 weeks, to radically reduce the amount of visceral fat around his organs and cure himself of type two diabetes. He describes his experience in this video.

There are many different ways to incorporate periods of fasting into your life. In fact we already fast every single day while we sleep. By eating dinner at 7 pm, and breakfast at 7 am, you are already incorporating at 12 hour fast into your daily routine. The simplest form of Intermittent Fasting is simply to skip breakfast. Making lunch your first meal of the day at 12 pm, and dinner your last meal at 7 pm, reduces your eating window to 7 hours, giving you 17 hours of fasting every single day.

Fasting experiences

On YouTube people have been experimenting with fasting for prolonged periods to treat all manner of ailments. The video that sparked my interest in the subject of using fasting to promote healing was this one.

I spent several evenings looking through videos on YouTube and found people using fasting to treat back pain, acne, and digestive problems like IBS and Crohn's disease, among other things. Many of these people reported positive results. One of the best videos I've seen was by a guy who did a 21 day water fast, which he found to be the most effective treatment he had ever had against the symptoms of Lyme disease.

This was sufficient to encourage me to explore the subject further, armed with a few terms I'd picked up from the videos.

What is Autophagy?

From the Greek αὐτός or auto, meaning self, and φαγεῖν or phagein, meaning to eat, the literal translation is self eating. It is a process that occurs inside cells, whereby parts of the cell are digested, being broken down into smaller components which can be used as a source of energy and for cellular maintenance.

Before we look a little deeper, let's remind ourselves what a typical animal cell looks like with the aid of this diagram by Tim van de Vall. The cell consists of an outer membrane, enclosing a cavity full of protein rich fluid called cytoplasm, in which are floating a variety of specialised structures called collectively organelles, as in small organs, which are labelled on the diagram. There are descriptions of each on Tim's site.

Lysosomes, are one of these organelles and there are hundreds of them in a single cell. They are filled with an acidic fluid containing inactive enzymes capable of hydrolysing, that is digesting complex molecules into simpler molecules. Proteins are broken down into amino acids, carbohydrates into simple sugars, and lipids into single fatty acids (NHGRI). Bacteria and viruses that have penetrated the cell may also be digested by Lysosomes (Antunes et al). This digestion is activated when a Lysosome merges with another organelle.

During the process of autophagy, intracellular components and other debris floating around in the cytoplasm are swept up and enclosed inside an autophagosome. Autophagy is generally thought to be a nonselective degradation system (Mizushima). Subsequently the autophagosome merges with a lysosome, activating the enzymes from the lysosome and digesting the contents. The recycled products of this digestion are then released into the cellular cytoplasm. The process is illustrated in this picture below, from Boya et al.

As the diagram suggests, Autophagy is induced in response to periods of stress. Autophagy is upregulated in response to extra or intracellular stress and signals such as starvation, growth factor deprivation, Endoplasmic Reticulum (another of the organelles) stress, and pathogen infection (He & Klionsky). A lack of any essential nutrient can induce autophagy (Mizushima). In other words Autophagy increases when your body has a shortage of energy or nutrients. Starvation and Hypoxia (shortage of oxygen) both reduce respiration, leaving your body with a shortfall of energy it must find from elsewhere.

I like to summarise the process simply as intracellular cannibalism or intracellular recycling. Too little Autophagy would lead to a build up of debris in the cytoplasm which you can imagine will hinder cellular function. Malfunction (read low levels) of autophagy contributes to a variety of diseases because efficient sequestration and clearance of unneeded or damaged cellular or nonself components is crucial for cell survival and function (He & Klionsky). Too much Autophagy would lead to a shortage of the organelles and proteins the cell needs to function, assuming Mizushima is right that the process is non-selective.

Medical research into Autophagy

Autophagy is one instance were medical researchers are just as excited about the prospect of regulating autophagy for healing, as YouTubers are online. Many of these papers are available to read online. They show that modulating autophagy has a role to play in the treatment of a vast number of infections, diseases and other medical conditions. These are just a handful of those discussed in the medical literature.


Dietary restriction has been shown to reduce the development of cancer, reducing tumor incidence and increasing the effectiveness of chemo and radiotherapy. When Intermittent Fasting cycles were combined with chemotherapy, tumor growth was slowed and overall survival was prolonged in breast cancer, melanoma and neuroblastoma animal models (Antunes et al). Autophagy probably has a preventive effect against cancer, but once a tumor develops, the cancer cells could utilize autophagy for their protection (Jiang & Mizushima).

Crohn's disease and Colitis

Autophagy-related proteins are reported to be associated with Crohn's disease. However, these proteins also play roles in biological processes so it is unclear whether they relate to Crohn's disease via autophagy modulation (Jiang & Mizushima). Drugs that upregulate autophagy, such as everolimus and sirolimus, may be helpful for treating Crohn's Disease and Colitis. Everolimus has been used successfully for the prevention/treatment of Colitis and Crohn's in mice. Two patients with severe Crohn's were successfully treated with everolimus and sirolimus, showing reductions in serum inflammation markers and of endoscopic appearance indicating that autophagy might be used for prevention of inflammation in Crohn's disease (Brest et al).


Dietary restriction has been shown to reduce the development of diabetes (Antunes et al). Type 1 Diabetes is an autoimmune disease which attacks pancreatic beta cells, leading to loss of insulin secretion. Inflammation from the immune response may contribute to beta cell death. Type 2 Diabetes is caused by resistance to insulin combined with a failure to produce enough additional insulin to compensate for the resistance. It is also mediated by an inflammatory mechanism. Autophagy is a significant regulator of immunity response and evidence shows that efficient autophagy can prevent inflammatory responses (Wang et al).

Lyme disease

Borrelia burgdorferi, the causative agent of Lyme disease, stimulates a series of inflammatory events to eliminate the infection. Studies have shown the importance of cytokine IL-1b (a protein secreted by the immune system) in response to Borrelia, with high amounts it found near the location of erythema multiforme lesions after tick bites. Autophagy can modulate the IL-1b response, with inhibition of autophagy promoting the secretion of IL-1b. Mice with reduced autophagy were found to have increased joint inflammation resulting from Lyme disease. Increasing autophagy has the potential for anti-inflammatory therapies in Lyme disease (Buffen et al).

Neurodegenerative disease

Studies provided evidence that the deficiency of autophagy is a contributing factor to human neurodegenerative diseases. However, the exact mechanism remains to be clarified (Jiang & Mizushima).

Stem cell function

Studies suggest that stem cell function could be modulated by targeting autophagy. A better understanding of the mechanisms could hold significant promise for the development of new therapies for haematological, muscular and neurological diseases, as well as for some cancers (Boya et al).


As we have discovered, fasting increases autophagy in the cells of the body, clearing out our cells and recycling all the rubbish into useful products which can be used for cellular maintenance. By clearing out deformed proteins, bacteria and viruses it increases immunity within our cells.

At the same time increasing autophagy has been found to decrease inflammation resulting from the immune response in conditions such as Crohn's disease, Diabetes and Lyme Disease.

When it is working efficiently, autophagy functions as intra-cellular immunity, digesting any mutant proteins, bacteria or viruses long before they can do harm by taking over and spreading to other cells. This solves problems quickly, without the body needing to call upon more drastic forms of extra-cellular immunity, which cause so much collateral damage in the form of inflammation.

The benefits of upregulating autophagy may be accessed through fasting, which can be as simple as skipping breakfast. Once you have mastered this you can progress to skipping lunch and completing a full 24 hour fast. Gradually you can work up to longer fasts of 36, 48 even 72 hours, listening to your body as you go and giving it time to adapt. Longer fasts allow you to reap the benefits of autophagy, along with other benefits like lowering blood sugar and insulin, increasing ketogenesis, and increasing growth hormone.

I have gone for months skipping breakfast, before falling back into old habits, I regularly do 24 hour fasts, and the longest I have fasted to date was 48 hours. I broke the fast as I was struggling to concentrate at work. You have to work up to it, and train your body in the process. When I'm fasting I have a cup of fresh coffee in the morning, a green tea in the afternoon, and water the rest of the day. You don't need to limit yourself to just water, and I certainly wouldn't drink distilled water or even worse deionised water. Ultra-pure water is aggressive and drinking it will draw out the minerals from your body, which is very the opposite of what you need to doing to be healthy.


Autophagy seems to be of fundamental importance for health, not only for combatting disease, but even more so for preventing disease in the first place. Since harnessing the power of autophagy can be as simple as skipping breakfast... why wouldn't you?




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