Autophagy: The Critical Fasting “Switch” to Purge Waste and Fat

From the prevention of disease to total-body cellular rejuvination and anti-aging, these autophagy benefits will inspire you to schedule a few longer fasts into your routine.

Look at autophagy as the housekeeper who cleans your room when you’re not around. Except instead of your room – it’s your body that gets the reboot – purging itself of old waste and disease without you even lifting a finger.

What is Autophagy? 

Autophagy is a protective cleansing mechanism that removes all the old, broken, and damaged cells from your body that are no longer serving you. Autophagy is initiated only once your body has been depleted of all its readily available food energy – in turn, “flipping the switch” to using stored waste matter as fuel instead.

Look at it as a massive clean sweep throughout your body, as defective cells and proteins are burned through for energy – in turn purging your system of built-up waste matter and damaged and diseased cells. Once your cellular systems are cleared of old waste, your body can then usher in beneficial new cell growth and cellular regeneration.

Autophagy Timeline

18-20 hours into fast

The autophagy process is initiated. Many experts agree that around the 18-20 hour mark, autophagy begins in most individuals. 

20-48 hours into fast

24 hours into a fast, nearly all individuals will be in ketosis. Your body makes the critical switch to using fat for fuel, and for the next 24 hours, Human Growth Hormone levels skyrocket. Your body becomes a fat-burning machine and the benefits of autophagy are in full effect.

48-72 hours into fast

Autophagy peaks at nearly 300% what it was at 24 hours.

Intermittent Fasting and Autophagy

The thought of fasting for long periods can be overwhelming at first, as most of us are used to consuming food from the moment we wake up to the time we go to bed. Luckily, intermittent fasting has helped bridge this intimidating fasting gap for many individuals, allowing them to ease into the process and begin reaping some of the many great health and weight loss benefits. 

There are countless ways to do intermittent fasting. The beauty of this lifestyle is that it can be adjusted to fit your unique needs and schedule. Many beginning fasters opt to do the 16:8 fast – which involves a 16 hour fasting period followed by an 8-hour eating window. This simple method is arguably the least disruptive, as it only requires you to skip breakfast (or dinner) to accommodate the larger window. 

While this fasting schedule can still lead to some weight loss, insulin levels only really start showing a decrease beyond 18 hours of fasting, ideally around 24 hours–a full day of fasting. For this reason, those looking to initiate autophagy tend to follow a schedule closer to the 5:2 method – which allows for two 36 hour fasts per week.

Since autophagy only happens when the cells are stressed and are forced to “eat themselves” to conserve energy, fasting for a very short period will not trigger this mechanism. Your body must first deplete itself of all readily available food energy and stored glucose and glycogen supplies. Once these systems have cleared, the process of autophagy begins.

Benefits of Autophagy

From improving overall health and wellbeing to preventing and reversing loose skin, below are some compelling reasons to include some longer fasts into your routine so you can begin reaping the incredible health benefits of autophagy.

Cellular Renovation

Studies suggest that autophagy may help our cells adapt better to stress. Imagine a cup full of old, stale water. Pouring clean water on top doesn’t do you much good – it’s still going to be mostly stagnant water. What you really need to do is start fresh. Pour the old water out, then add clean water to the empty glass.

Autophagy operates in a similar matter, except instead of dumping the whole glass out, your body uses up the old proteins and broken, defective cells for fuel first. Not only does this help eliminate old stored waste, but it also opens the door to new and healthy cell production and growth.

Disease Prevention

While most people fast for the weight loss benefits, fasting-induced autophagy may also help prevent disease and treat certain medical conditions. Research suggests that autophagy is essential for cellular homeostasis and may help protect the brain and body from disease caused by imbalance or buildup caused by the accumulation of harmful waste.

Scientific trials are still underway studying autophagy’s ability to treat neurodegenerative diseases and psychological disorders. In 2015, researchers concluded that autophagy may aid in the treatment of schizophrenia. While there is still much to be researched in the field of autophagy – specifically in its ability to treat and prevent disease – experts are hopeful that autophagy may be helpful in the treatment of certain psychological conditions.

Research has also shown that autophagy can impact the body’s mTOR, a protein that affects aging and depression. There is potential for autophagy to target this protein to help with the development of antidepressants or other therapeutic methods.


Although most fasting studies use animals, many of the results can also be applied to humans. One study administered on mice found that the mice subjected to fasting-induced autophagy lived longer than the group who followed a continuous eating pattern. These findings support a lot of the research concluding that autophagy is a critical component of longevity. 

Loose Skin

The breakdown and recycling of loose skin may be one of the most unusual (and appealing!) benefits of autophagy. While it may sound too good to be true, studies have shown that there are many anti-aging faculties are play once autophagy is triggered, some of which may indeed help prevent and reverse saggy skin. First-hand accounts support these findings, suggesting that fasting-induced autophagy may help counteract excess skin issues caused by dramatic weight loss.

The term autophagy literally means “self-eating,” but in order to initiate this process, one must first cut off all external food supply. While our fat stores provide our bodies with backup energy reserves, our excess skin and old damaged cell waste account for quite a bit of extra proteins that our bodies also dip into once food sources have been depleted. It’s important to note that while keto dieters may still benefit from fat loss around the clock thanks to ketosis, only those following a fasting schedule that includes longer 24+ hour fasts can reap the full benefits of autophagy.

The Autophagy Reset

Out with the old, in with the new! Just like you would first remove clutter and trash before making over your home, it is vital to occasionally “clear out” the garbage in your body in order to invite in new growth. Once you make space for cellular destruction, you can finally reap the benefits of cellular regeneration and rejuvenation. Think of autophagy as the Marie Kondo method of tidying up – except instead of your house, it is your old and damaged body parts being purged so fresh new systems can take their place.

Autophagy is serious business. But luckily,  it’s also pretty straightforward. By mixing a couple of longer (24+ hour) fasts into your schedule, you can begin benefiting from this healing process almost immediately. 

Get the ball rolling and set yourself up for success with my top 7 intermittent fasting tips for beginners that helped me lose over 70lbs and keep it off.

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