See which physiological phase your body is in as you fast.
As you fast, your body moves through distinct hormonal and metabolic phases. Enter how long you have fasted and your target protocol to see where you are.
Enter your values above to see your result.
Progress = (hours fasted / target) × 100. Phases: 0–4h digestion · 4–12h glycogen · 12–18h lipolysis · 18–24h ketosis+autophagy · 24h+ robust autophagy.
In the first hours after eating you digest and store. Around 4–12 hours you burn stored glycogen; after ~12h, lipolysis ramps up and you burn fat.
By 18–24 hours, ketosis and autophagy (cellular cleanup, Nobel 2016) begin. Fasting works by lowering insulin — a hormonal reset, not a calorie trick.
Note: fasting is not for everyone — pregnancy, breastfeeding, eating disorders or type 1 diabetes.
Meaningful autophagy generally begins around 18–24 hours of fasting and increases beyond that.
Educational tool — does not replace medical advice. Discuss your results with your doctor.