Advanced Protocol · Warrior Diet
20:4 Fasting Calculator
The 20:4 Warrior Diet — fast for 20 hours, eat 1–2 meals within a 4-hour window. Deep ketosis and autophagy every day.
Step 1 — Choose Your Protocol
Advanced (Warrior Diet) — fast 20h, eat within 4h.
Step 2 — Personalise Your Schedule
Your eating window starts from this time
🎯 Your Goal
⏱ Fasting Stages
What Happens Inside Your Body
Live biological stages during your 20-hour fast — each backed by peer-reviewed research.
Last Meal Completed
+0hYour fasting clock starts now. Digestion begins and your body processes the glucose from your last meal.
📄 Mayo ClinicDigestion Phase
+2hBlood glucose peaks and insulin is released. Your body is actively digesting and storing nutrients from the last meal.
📄 NIH — Metabolism OverviewBlood Sugar Stabilizing
+4hInsulin levels begin to drop. Blood sugar returns toward baseline. Your body shifts from storing to maintaining.
📄 PubMed — Insulin & Glucose DynamicsGlycogen Depleting
+8hLiver glycogen stores are running low. Your body begins mobilising free fatty acids as an alternative fuel source.
📄 Cahill GF Jr — NEJM 1970🔥 Ketosis Begins
+12hGlycogen stores are nearly depleted. Your liver starts producing ketone bodies from fat — your brain switches to fat-burning mode.
📄 Cahill GF Jr — NEJM 1970✨ Autophagy Activates
+16hCellular housekeeping begins. Your cells start breaking down damaged proteins and organelles — a key anti-aging mechanism.
📄 Levine & Kroemer — Cell 2008* Biological timelines are approximate and vary by individual. Sources: PubMed, NIH, Cell journal.
The 20:4 Warrior Diet
Originally coined by Ori Hofmekler, the Warrior Diet advocates fasting during the day and eating one large meal at night within a 4-hour window. Modern adaptations allow flexibility on the eating window timing.
At 20 hours of fasting, you are well into deep ketosis and peak autophagy. This protocol is for experienced fasters who have adapted to 16:8 and 18:6. Not recommended for beginners.
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