Fasting Schedules · Evidence Limits
Autophagy Calculator
This tool calculates an eating and fasting schedule. It cannot measure autophagy, predict its onset, or identify a safe fasting duration for you. The example schedule is not a recommendation.
Step 1 — Choose Your Protocol
Intermediate — fast 18h, eat within a 6h window.
Step 2 — Personalise Your Schedule
Your eating window starts from this time
🎯 Your Goal
⏱ Time Checkpoints
Your Fasting Timeline
Elapsed-time checkpoints for a 18-hour schedule. These do not measure metabolic changes.
Fast Started
+0hThe clock measures time since your last calories. It does not measure digestion or metabolic changes.
📄 Mayo ClinicEarly Fasting
+2hDigestion and nutrient absorption vary with the meal and the individual.
📄 NIH — Metabolism OverviewBetween Meals
+4hYour body uses a mixture of fuels. Time alone cannot identify your blood glucose or insulin level.
📄 PubMed — Insulin & Glucose DynamicsOvernight Interval
+8hAn overnight interval may include sleep. Glycogen use varies with diet and activity.
📄 Cahill GF Jr — NEJM 197012 Hours Elapsed
+12hTwelve hours is a time checkpoint, not a diagnosis of ketosis. Ketone production varies between people.
📄 Cahill GF Jr — NEJM 197016 Hours Elapsed
+16hSixteen hours does not establish autophagy activation. There is no validated universal human autophagy timer.
📄 Levine & Kroemer — Cell 2008Time checkpoints are educational, not a recommendation to extend your fast.
When Does Autophagy Start?
Autophagy (from Greek: self-eating) is the process by which cells break down and recycle damaged components. It was the subject of the 2016 Nobel Prize in Physiology or Medicine (Yoshinori Ohsumi).
There is no validated universal fasting duration that switches on or maximizes autophagy in humans. Cellular recycling is a regulated process, not a timer event. Do not extend a fast to chase an estimated repair stage.
Source: Cleveland Clinic — Autophagy and the limits of human timing evidence
Medical Disclaimer
This tool provides estimates for informational purposes only. Always consult a licensed healthcare provider before beginning any fasting protocol — especially if you are pregnant, have a history of eating disorders, diabetes, or any other medical condition.
Sources: Mayo Clinic · NIH · PubMed