Autophagy: Definition, Fasting, Benefits and More

Written by Ahmed Zayed | Last updated on August 4, 2023

There are a lot of different cells in your body and one thing that they have in common is the ability to become somewhat of a carnivore.

When your body goes without calories for some time, there’s a process that activates - and it’s called autophagy. 

Many describe autophagy as a process where a cell would “eat itself” in order to recycle some of the waste and unnecessary materials that are building up inside of it.

This recycling process is actually really important, as it makes those materials in the cell usable again. 

While autophagy happens naturally, there are a couple of ways to induce it yourself. This can yield some potential benefits for you, but having a good understanding of autophagy first is important.

Read on to learn more! 

Mechanisms Of Autophagy

There are actually a couple of mechanisms that play a role in autophagy, from the initiation of the process all the way to the re-usage of nutrients that were obtained from degraded components [1]. 

A variety of factors can trigger the initiation of autophagy. Some examples include stress, cellular damage, and starvation. When this initiation is triggered, then autophagosomes start to form. 

Now, these autophagosomes analyze your cells and they form around components that are damaged. They also form around some organelles, proteins, and other components that are not needed by the cell. 

At this point, certain enzymes and proteins get added to the autophagosome - and this leads to the maturation of the autophagosome.

Once this happens, the autophagosome fuses together with another compound called lysosome. 

The lysosome is actually a cell organelle and when it fuses with the autophagosome, it exposes the autophagosome to digestive enzymes. 

The next step is degradation. The digestive enzymes now get to work and start to degrade all of those unnecessary and damaged components that are part of the cell - the ones they previously formed around. 

And as these compounds are degraded, nutrients are extracted from them. This is where the final step of autophagy happens - the cell can now use these nutrients that come from the degraded materials to perform certain functions and to contribute to its survival. 

Autophagy Signaling Pathways

There are certain pathways involved in signaling autophagy and each of them plays an important role in ensuring this particular process is activated and works effectively [2].

While there is still a lot to discover by scientists, they have already made a couple of findings. 

mTOR is one particular pathway that seems to play a crucial role in autophagy signaling. This is a protein kinase that is involved in both metabolism and the growth of cells. 

When autophagy activates, it inhibits the mTOR pathway, which gives cells a chance to break down those unnecessary and damaged components. Thus, when mTOR is turned off, it triggers a reaction that signals autophagy. 

During autophagy, one particular pathway that is activated would be AMPK. It’s also a protein kinase and plays a role in cellular metabolism. This particular pathway actually helps to ensure unnecessary components in a cell are broken down effectively. 

ULK1 and Atg12 are also pathways that are involved in autophagy. In fact, ULK1 plays a really important role in ensuring autophagy is “initiated”. If you recall the previous section, we discussed initiation as the very first step or mechanism in autophagy. 

For the ULK1 pathway to be effective and to remain stable, a pathway known as Beclin1 is also required. mTOR then inhibits the function of the Beclin1 pathway as autophagy activates to ensure those cellular components can be broken down. 

When activated, the Atg12 pathway plays a role in ensuring autophagosomes can be formed around the materials in the cell that need to be degraded later on. 

Benefits Of Autophagy For Health And Longevity

There are several reasons why autophagy plays really important roles in both health and your lifespan. Let’s take a closer look at some of the most important benefits, especially when considering modulating and stimulating the process:

  • It may help to reduce the risk of cancer by destroying components in cells that could eventually become cancerous. 

  • By recycling damaged proteins in brain cells, the risk of neurodegenerative diseases could also decline.

  • Autophagy helps with metabolic health, reducing low-grade inflammation and potentially also lowering the risk for heart disease, type 2 diabetes, and stroke. 

  • It’s a vital process to ensure the immune system continues to function properly.

Ways To Stimulate Autophagy

There are different ways to stimulate autophagy and to make it more effective. When you want to maximize on the benefits that autophagy can provide, it’s important to understand these stimulatory options. 

Many of these things are easy to incorporate into your diet, but there are also other interventions apart from lifestyle factors that can do wonders in ensuring autophagy is activated and works properly.

In this section, we’ll take a closer look at a couple of ways in which you can stimulate autophagy yourself. 

Dietary Changes That Can Boost Autophagy

One of the most popular ways to activate autophagy yourself is through dietary changes.

See, autophagy is something that activates in a state of starvation. And if you decide to introduce fasting into your own lifestyle - well, that’s a way to starve your body. 

When your body reaches a certain stage of starvation during a fasting window, then there are pathways that activate. In response to these pathways, a chain of reactions then eventually causes the activation of autophagy. 

Think of it like this: when you’re fasting, your cells aren’t getting new nutrients. And when this happens, they activate a “mode” where they “eat themselves” - but in such a way that wasteful materials (think damaged and unneeded components) are turned into nutrients. 

It’s a survival mode of your cells that allows them to make nutrients themselves when you are not supplying your body with nutritional content. 

Ways To Modulate Autophagy

Fasting is not the only way to modulate autophagy. See, there are several other factors involved in the process of autophagy activation - including stress and dietary changes. 

Exercise is a particularly good option if you want to boost your autophagy processes. It has been found that resistance exercise training and high-intensity interval training are the most effective options when it comes to modulating autophagy. 

You can also turn to a ketogenic diet if you want to make dietary changes that could help to improve your autophagy.

The ketogenic diet actually mimics fasting effects in some ways and when you combine it with a fasting lifestyle, you can actually boost the effects of autophagy. 

Hot and cold exposure might also be a way to modulate autophagy. This causes cold and hot shock proteins to be released in your body.

This creates a stress response in your body, which could be used to stimulate autophagy. 

Pharmacological Interventions

Researchers have also made progress in the use of pharmacological interventions in order to assist with the modulation of autophagy. Some studies have even shown that this type of technique could be useful in patients who have autoimmune diseases. 

In particular, they found that inducing autophagy through pharmacological interventions could be especially useful in lupus erythematosus and inflammatory bowel disease [3]. 

Autophagy And Age-Related Diseases

Autophagy plays a big role in ensuring your cells can recycle damaged materials and components that are no longer needed.

But when things go awry and autophagy doesn’t happen as it should, then these components continue to build up in your cells. 

And over time, it can become a problem. If there are a lot of waste components in your cells, they become less functional - and less functional cells cannot do their jobs properly.

This creates an opportunity for the development of disease. 

Cellular dysfunction due to poor autophagy has been associated with neurodegenerative diseases, such as Parkinson’s and Alzheimer’s disease [4].

Additionally, cancer and metabolic syndromes also seem to hold a connection to improper functioning of the autophagy processes. 

Techniques To Study Autophagy

There are a couple of techniques that researchers can turn to when they study autophagy. Electronic microscopy is a popular technique, where certain techniques are used to visualize autophagosomes. 

These autophagosomes are only present when autophagy is active. 

Immunohistochemistry is another technique that has shown promise in the study of autophagy. It’s a technique where scientists will attempt to identify the presence of LC3 and other proteins that are related to autophagy within a specific cell. 

A flow cytometry test can also be used to determine how many autophagosomes are present in a given cell. This can be a useful option when measuring the overall efficacy of autophagy in a study subject. 

Challenges And Limitations In Studying Autophagy

While a lot of research has already gone into the field of studying autophagy, there are still a few challenges and limitations faced.

Since it’s such a complex process, researchers do not have a complete understanding of the entire process. 

The fact that there are many things involved in regulating autophagy makes it even harder, plus it’s important to note that the process is also dynamic. 

Future Research In Autophagy

Researchers will continue to look at how autophagy can be measured and studied with greater precision in the future.

An emerging interest in how autophagy works and affects different cells in the body is also something that researchers are actively looking at. 

In the future, we may also find out more about the exact role that autophagy plays in diseases and how it can be used as a target to develop new drugs and therapeutic interventions.

Frequently Asked Questions

How long do you have to fast for autophagy?

There are mixed results and opinions in terms of how long you should fast for to induce autophagy.

Age, your overall health, and several other things can affect how long it takes toa activate autophagy. The process usually begins after 12 to 18 hours of fasting. 

How do I know if I am in autophagy?

There aren’t really obvious signs that tell you that autophagy has been activated.

Some people do explain that they feel less hungry and they have a boost in energy. Better mental clarity is also an experience that people have reported while fasting for autophagy. 

Is autophagy fasting healthy?

Fasting with the goal of inducing autophagy can be a healthy part of your lifestyle.

But, it is still important to ensure you do not fast for too long. Going without food for a long period of time can be hazardous for your general well-being. 

Why is autophagy bad for you?

Autophagy is not really bad for you, but there are some cases where it can go out of control.

This is usually the case when you implement strategies that promote autophagy for a longer period of time, which can cause cells to die when they are needed for balance in your body. 

Is autophagy better than ketosis?

One isn’t really better than the other. Ketosis and autophagy are actually two very different processes. It’s also possible to activate autophagy while you are in ketosis.

With this said, it’s important to be careful when trying to use both of these methods simultaneously. 


When your body is starving, it activates autophagy. And through this process, your cells can recycle organelles and proteins that don't belong inside them. It helps to make the cells healthy and to improve how well they are able to function. 

There are pharmaceutical interventions that are helpful, but you can also turn to natural things, like lifestyle changes, to make autophagy more effective. 

Follow the tips we shared in this article to help you activate this process for better health and to improve cellular survival. 


  1. An overview of autophagy: Mechanism, regulation and research progress. Retrieved from  

  2. Autophagy: cellular and molecular mechanisms. Retrieved from 

  3. Pharmacological insights into autophagy modulation in autoimmune diseases. Retrieved from 

  4. Autophagy, Cellular Aging and Age-Related Human Diseases. Retrieved from 

About the author 

Dr Ahmed Zayed is a medical resident specializing in plastic surgery with years of experience in the field. He is also a writer for top-rated websites including Washington Post, Chicago Tribune, ConsumerHealthDigest, and Huffington Post

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