Want to know what the BEST THING about intermittent fasting is? It’s AUTOPHAGY. This article is about autophagy and fasting.

The Best Thing About Fasting

There are many reasons why people do intermittent fasting, starting from weight loss and ending with convenience.

Although restricting your eating window within a certain time frame makes it very easy to create a caloric deficit, using IF for fat loss is just the superficial benefit.

The best thing about intermittent fasting is autophagy.

I did some research, and in this article, I’m going to tell you what I learned about autophagy and how you can benefit from it when doing intermittent fasting.

What is Autophagy

Autophagy or autophagocytosis in fancy science language translates from the Ancient Greek word autóphagos which means self-digestion or -devouring.

Autophagy is a natural process by which our cells disassemble and remove their dysfunctional components[i]. It’s basically the recycling of cellular waste and taking out the trash.

Autophagy puts you into a catabolic state, which breaks down your own tissue, as opposed to an anabolic one, which is about building up.

There are a ton of benefits to autophagy:

Reduction in inflammation

Improved immune system

Slows down the aging process [ii]

Eats up cancerous cells and tumors

Kills infectious particles and toxins[iii]

Inability to cause autophagy makes rats fatter, less active, have higher cholesterol and impaired brain function[iv]

How Does Autophagy Work?

When you trigger autophagy, you allow the organelles of your healthy cells to hunt out dead or diseased cells and then eat them.

This involves forming a double membrane around the cell that’s going to be eaten called an autophagosome. The autophagosome then dissolves the sick cell or the toxic protein and creates energy.

What regulates autophagy?

The main signallers of autophagy are two protein kinases mTOR and AMPK[v][vi].

mTOR or mammalian target of rapamycin is responsible for cell growth, protein synthesis, and anabolism. It promotes the activation of insulin receptors and will make the body build new tissue.

AMPK or AMP-activated protein kinase is a fuel sensor that is involved with balancing energy deprived states

MTOR inhibits autophagy because it makes your body grow, which requires conserving energy and upregulating the metabolism, whereas AMPK supports autophagy due to the energy deprived state.

Autophagy and Caloric Restriction

The reason intermittent fasting induces autophagy has to do with caloric deprivation.

Nutrient starvation allows unneeded proteins to be broken down and recycled into amino acids that are essential for survival[vii][viii].

Research has shown that consuming fewer calories prolong your lifespan. HOWEVER, to get the lifespan-prolonging benefits of caloric restriction you need autophagy.

In one study on mice and flies, they found out that if you inhibited autophagy but still fed the animals fewer calories, they didn’t live longer, but the ones who were proficient at causing autophagy did[ix].

This is a very important point – it means just going on a weight loss diet while not allowing autophagy to do its work will actually be bad for your longevity and health. Long-term caloric restriction leads to micronutrient deficiencies and more oxidative stress.

The reason you get kicked out of autophagy, even when eating fewer calories, is eating too frequently. If you consume protein or carbohydrates, you trigger mTOR. Even as little as 50 calories or just 2 grams of leucine will shift you from a fasted state into a fed one and makes you suppress autophagy[x].

You Need to Fast to Trigger Autophagy

You would be better off by consuming no calories at all and doing intermittent fasting, rather than breaking your fast with a small amount of calories and stopping autophagy.

That’s the reason I believe everyone should practice some form of intermittent fasting. If not daily then at least periodically throughout the week.

Imagine if you’re eating breakfast, lunch, and dinner

You stop eating at 8 PM, you fast throughout the night, and you consume your first bit of calories at 8 AM.

There’s a 12-hour space between your meals, but it takes about 6-8 hours for your body to first digest the food and then enter a fasted state.

You really only start fasting in the middle of the night and you’ve done so for maybe 6 hours by the time of breakfast.

When you’re in a fed state, autophagy is low because of mTOR and insulin. As these fuel sensors drop, autophagy rises.

How Long Does It Take to Trigger Autophagy?

I tried searching for an answer in studies but it seems there is no clear answer to this. Autophagy happens in varying degrees in varying tissues.

Generally speaking, as soon as your blood sugar levels get low and you suppress mTOR and insulin, you’ll begin to show some signs of autophagy.

You would have to be in a mild ketotic state with depleted liver glycogen to let these processes take place. This can happen already within 16-24 hours.

However, this is a very mild response and autophagy starts to really ramp up after the first 48 hours. To get a really good effect from autophagy, you’d have to fast for 3-5 days.