If you’ve been researching the keto diet or fasting for a while, you’ve probably stumbled across the term “autophagy” before.
Autophagy literally means “self-eating,” and it’s a powerful biological process involving the breaking down and recycling of old cells. In certain cases, autophagy can be extremely beneficial for health and wellness.
In this article, we review the benefits of autophagy and how to kickstart the autophagy process for improved health.
What is Autophagy?
Autophagy is one of the body’s built-in recycling processes.
It occurs in response to cellular stress, usually after calorie and/or nutrient restriction. To keep cells functioning in spite of this restriction, autophagy allows your body to break down unneeded or damaged cell components and recycle them into useful materials (*).
This allows cells to keep functioning even though your body isn’t receiving the raw material it needs to create new cells or tissues.
Autophagy is neither good nor bad. Whether it is a welcome process really depends on several other health-related factors. In certain cases it may be harmful, while in other cases it could be very beneficial.
Many people are interested in the therapeutic benefits of autophagy for anti-aging and brain health. Additionally, although there’s currently no published research to support this claim, many people who have lost large amounts of weight using keto or fasting credit autophagy for minimizing how much loose, sagging skin they had after weight loss.
What Happens During Autophagy?
During autophagy, the body breaks down cell components that are damaged or no longer needed in order to create new, usable cellular material.
Autophagy occurs in five phases (*):
- Induction: In this phase, a number of biochemical and hormonal messengers signal autophagy to begin. At this point a specialized structure called a phagophore begins to form at the site of “junk” cellular material.
- Nucleation: Nucleation involves the drawing of additional molecules (such as certain specialized proteins) to the growing phagophore.
- Elongation: The phagophore continues to grow or elongate and completely envelopes the target material. This entire structure is now known as an autophagosome.
- Fusion: The autophagosome fuses with a lysosome, a specialized cellular structure that contains digestive enzymes. An autolysosome is formed when the two structures are fused together.
- Degradation: The enzymes in the autolysosome break down the swallowed material into their most basic components, which the body can then reuse to create new structures.
Depending on which source you refer to, the steps may be divided differently or have slightly different names. However, the process remains the same no matter how the steps are numbered (*).
What Causes Autophagy?
Autophagy is a response to stress from nutrient and calorie restriction.
It can occur in a number of states of disease or sickness, like cancer or HIV/AIDS (*, *).
However, it can also be induced through fasting or calorie restriction.
Autophagy is triggered when the body is deprived of the nutrients or calories it needs, so it begins to break down unneeded, damaged, or “junk” parts of cells to create materials that it can use.
Can You Induce Autophagy?
Yes, it is possible to induce autophagy. Here are several different ways this can be done:
- Calorie restriction: The body signals autophagy to begin when there is a lack of nutrition, especially proteins and carbs. One way to accomplish this is through an extremely calorie-restricted diet (*).
- Extended fasting: Fasting is considered the most reliable way to induce autophagy. Most experts recommend long fasts for autophagy induction, consisting of a fasting window of anywhere from 18 hours to 3 days. Please note that you should not attempt extended fasting without medical supervision (*, *).
- Ketosis: A low-carb, high-fat ketogenic diet causes the body to enter a state of ketosis, where it burns ketones from fat as its primary fuel source. Ketogenic diets are sometimes called “fasting-mimicking” because they provide many of the benefits of fasting, including autophagy induction (*).
- Vigorous exercise: Finally, intense exercise may help to induce a stage of autophagy — and may be more effective at inducing autophagy if you are already in ketosis or a fasted state (*).
Why is Autophagy Important in Cellular Health?
Autophagy is one of the body’s “recycling” systems. It helps flush old or damaged cell components and tissues out of the body so that they can be replaced with healthier cell material.
It’s an important part of the body’s natural immune response, and it helps the body function effectively in physiologically stressful circumstances.
Other Health Benefits of Autophagy
Autophagy has been linked to anti-aging and improved cellular health.
This means that autophagy could have widespread benefits on many different facets of health.
However, researchers are particularly interested in autophagy for improving cognitive disorders like Alzheimer’s disease.
Alzheimer’s is thought to be caused by a build-up of beta-amyloid plaques in the brain, so researchers are pursuing autophagy as a potential solution to help break down these plaques (*).
Autophagy can also be used to break down disease-causing pathogenic cells, like bacteria and viruses (*).
Link Between Autophagy and Diseases
Autophagy is also a part of many different health and disease processes, including starvation and conditions that induce a state of cachexia (wasting) or anorexia (loss of appetite) — like cancer.
However, that doesn’t necessarily make autophagy a symptom or a complication of these conditions. In fact, autophagy is an adaptive response that helps the body continue to function in spite of starvation.
However, there are also some diseases and health problems that may be caused by dysfunction within the body’s normal autophagic processes. In particular, researchers believe that neurodegenerative diseases (like Parkinson’s and Alzheimer’s) and tumor development may both be linked to problems with autophagy (*).
Link Between Autophagy and Longevity
Autophagy may have a lot of potential in the realm of anti-aging and longevity.
According to Dr. Jason Fung of The Fasting Method, autophagy could also be called “rejuvenation.” This is because rejuvenation — replacing the old with new — is exactly what autophagy does (*).
However, as we age, autophagy becomes less effective — which may be one of the key drivers of biological aging. Still, various anti-aging compounds — like antioxidant triterpinoids and resveratrol — work by helping optimize autophagy effectiveness (*).
Researchers have also found that autophagy induction through time-restricted eating (a type of intermittent fasting) has also been linked to improvements in aging markers (*).
Frequently Asked Questions
How do I know if I’m in autophagy?
There’s no way you can definitively test for autophagy at home, but some signs that autophagy may be occurring in your cells are high ketone levels and a reduced appetite.
How long should you fast for autophagy to occur?
According to one study, autophagy occurred after an 18-hour fast. However, the process may become stronger in longer fasts of 2-3 days (*).
Does autophagy burn fat?
Yes, autophagy can burn fats in the body. However, you shouldn’t count on autophagy as a weight loss strategy. Weight loss can occur from fasting or following ketogenic diets, but this is through a separate process than autophagy.
How often should you be in autophagy?
There are no set recommendations for autophagy frequency. Many people practice intermittent fasting, which may be able to induce autophagy in as little as an 18-hour fast, on a long-term basis with no complications (*).
Are there any side effects of autophagy?
According to some research, excessive autophagy may damage the heart by causing the death of heart cells. If you have any concerns about autophagy, be sure to speak with your healthcare provider (*).
The Bottom Line
Autophagy is a biological process that allows your body to break down old, damaged, or dysfunctional cell components so that they can be reused.
It occurs in response to food restriction, so it’s a natural process in starvation and in people with wasting diseases like cancer. It can also be induced via calorie restriction, fasting, ketogenic diets, or exercise. Many people are interested in inducing autophagy to hep promote better cell health and increase longevity. Autophagy also shows promise as a treatment for neurodegenerative diseases like Alzheimer’s.
Although fasting is the most effective way to induce autophagy, it’s important to be very careful if you’re new to fasting. In fact, it’s a good idea to notify your doctor before you start a fasting regimen — especially if you have any pre-existing health conditions.