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Autophagy Calculator

Find out exactly when autophagy begins during your fast. Adjust for your last meal, activity level, and age to get a personalised estimate.

Autophagy begins in

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Start your fast to begin tracking

0% to autophagy

Fasting Phases

🍽

Fed

0-4h

▼

Catabolic

4-8h

🔥

Fat Burning

8-12h

⚡

Ketosis

12-18h

♻

Autophagy

18-24h

✨

Deep

24h+

Autophagy Onset

18h

--

Deep Autophagy

24h

--

Peak Autophagy

30h

--

Track this automatically in the app

Start your fast and let Fasted notify you the moment autophagy begins.

Important disclaimer

Autophagy cannot be measured without specialised laboratory testing. These timelines are based on research averages and are not a diagnosis or medical measurement. Individual results vary significantly. Consult a healthcare professional before undertaking extended fasts.

Understanding when autophagy kicks in during your fast is one of the most powerful motivators for extending beyond a standard 16:8 window. This calculator uses research-backed factors to give you a personalised estimate rather than a one-size-fits-all number.

Your last meal composition, activity level, and age all influence how quickly your body depletes glycogen and triggers the cellular recycling process. By adjusting these inputs, you can see how lifestyle choices today affect when autophagy begins tomorrow.

Frequently Asked Questions

How long do you need to fast to trigger autophagy?
Most research suggests autophagy begins around 18-24 hours into a fast for most people. However, the exact timing depends on factors like your last meal composition, activity level, metabolic health, and age. A low-carb last meal and exercise can accelerate onset by several hours.
What is autophagy and why does it matter?
Autophagy is your body's cellular recycling system. During extended fasting, cells break down and repurpose damaged proteins, organelles, and debris. This process supports immune function, reduces inflammation, and may protect against neurodegenerative diseases. Yoshinori Ohsumi won the 2016 Nobel Prize for discovering its mechanisms.
Does exercise speed up autophagy?
Yes. Exercise accelerates glycogen depletion, which is one of the key triggers for autophagy. Studies show that moderate exercise during a fast can bring forward autophagy onset by approximately 1-2 hours compared to remaining sedentary.
Can you measure autophagy at home?
No. Autophagy can only be measured through specialised laboratory tests. The timelines provided by calculators are based on research averages and should be treated as educated estimates. Individual results vary based on metabolic health, body composition, and other factors.
What are the signs you are in autophagy?
There are no definitive external signs of autophagy. Some people report increased mental clarity, reduced hunger (as ketones rise), and a sense of lightness during extended fasts. However, these are indirect indicators and not proof that autophagy is active.

Go deeper

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Autophagy Explained: Your Body's Built-In Recycling System

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Start your fast now and let Fasted notify you the moment autophagy begins

The Fasted app tracks your fasting phases in real time and sends you a notification the instant you enter the autophagy zone. Never miss the moment your cells start cleaning up.

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