Autophagy and fasting: Spring cleaning for your cells

Intermittent fasting is known to have many health benefits. One reason why it’s good for your body is that it stimulates a process called autophagy.

Autophagy is also called the fountain of youth and is at least partly responsible for the anti-aging effects of fasting.

Autophagy is a well-studied process in the medical field: Japanese cell biologist Yoshinori Ohsumi won the 2016 Nobel Prize for his discoveries of mechanisms for autophagy (1).

We take a closer look here at what autophagy is, why it is so vital for the body, and how you can promote autophagy with fasting.

Let’s dive in. 

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What is autophagy?

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The term autophagy is Greek and means “self-eating”. That doesn’t sound healthy, but it is an essential recycling process that takes place in every cell of the body. 

During this process, old molecules are broken down, and the building blocks are then used to build new molecules.

You can compare it to spring cleaning: autophagy gets rid of old stuff that isn’t used anymore, or that is in the way or interferes with daily tasks.

By replacing non-functional items with new ones, everything runs smoother and more efficiently again.

So you can see autophagy as a self-renewal process, and there are good reasons why autophagy is called “the fountain of youth”.

How fasting promotes autophagy

When you eat something, your cells get supplied with energy and nutrients. With these resources, the cells can build the molecules that they need to function.

As long as there is a constant supply of new resources, there’s no need to recycle old molecules. Once you stop eating, fewer nutrients reach the cells, and at some point, the cells have to recycle old molecules to build new ones–autophagy starts. 

You can compare it to a student who does not have a lot of money. When his kettle breaks, he will decide to get it fixed instead of buying a new one. Once he has a job and makes good money, time becomes more precious than money. He may then decide that buying a new kettle is much easier than fixing the old one.

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What are the benefits of autophagy?

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Autophagy is a stress response. We often see stress as something bad. Chronic stress indeed is–but occasional stress can be good. The famous saying, “What doesn’t kill you makes you stronger” holds some truth.

You know this from exercise. It stresses your muscles, but it is also necessary to build and maintain muscles.

The strongest inducer of autophagy is a lack of essential nutrients. For this reason, fasting is so powerful in promoting autophagy. The lack of nutrients is a clear stress factor. However, it is crucial and beneficial–as long as it is only temporary.

Brain health

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It is crucial to recycle proteins and other molecules in the brain regularly. Certain proteins in the brain can stick together and build up into so-called plaques. These plaques can cause neurodegenerative diseases, such as Alzheimer’s. By regularly breaking down proteins, autophagy can prevent plaque formation in the brain (2).

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Anti-aging

Autophagy decreases with age and is a hallmark of aging (3). Also, autophagy is impaired in many age-related conditions such as diabetes, heart disease, and neurodegenerative conditions, and problems with autophagy contribute to the development and progression of these conditions (4, 5, 6). Across the animal kingdom, it can be observed that fasting increases lifespan (7). Autophagy seems to be the main reason for this.

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Anti-inflammatory

Inflammation is a crucial response by the immune system to fight germs. Inflammation usually resolves quickly. When it doesn’t, and it becomes chronic, it is harmful to the whole body. Chronic inflammation increases the risk for many conditions, such as type 2 diabetes, autoimmune conditions, heart disease, and even cancer. Because autophagy helps to clear debris, it decreases inflammation (8).

How to induce autophagy?

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Fasting is the most powerful promoter of autophagy. But there are a few more things that can induce the autophagy process:

• Heat and coldness can both promote autophagy (9, 10). Sauna and cold showers are healthy for a reason!
• Exercise, especially endurance exercises such as jogging (11).
• Coffee: (12) Yes, your favorite morning drink can be good for your health. But for autophagy induction, you have to drink it black–without milk and sugar.

When does autophagy start when fasting?

As the autophagy benefits through fasting become better known, there is a pressing question: How long into a fast does autophagy kick in?

Unfortunately, there is no simple answer that applies to everyone.

First of all, there are many factors that influence it:  How active you are, the size of the meal before you start fasting, comorbidities such as diabetes, etc. 

Secondly, autophagy is not easy to measure in live organisms. For this reason, there are not many studies with proven, usable statistical data.

However, in one study with moderately overweight participants who were moderately active, autophagy could be detected after 18 hours of fasting (13). So, for the average person, 18/6 and possibly 16/8 intermittent fasting is sufficient to promote autophagy.

Bottom line

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Fasting stimulates different processes in the body. One such crucial process is autophagy–an essential recycling process that offers many health benefits. It promotes brain health, reduces inflammation, and can even slow down aging.

Different factors can induce autophagy, but the absence of food for a prolonged period is the most powerful. Research shows that an 18-hour fast can be enough to boost autophagy. 

Want to know more about the benefits of fasting? Check out our article on the benefits of intermittent fasting for women !