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Biohacking & Longevity · Cluster 02

Intermittent Fasting Window Planner

Plan your eating and fasting windows for 16:8, 18:6, or any IF protocol. Get a visual timeline, exact meal times, autophagy onset estimate, and fat-burning window.

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Your Fasting Window Calculator

Select a protocol and set your preferred eating start time

Your Fasting Schedule
🍽 EATING WINDOW
⏳ FASTING
12:0018:0000:0006:0012:00
Eating Window—
Last Meal / Fast Begins—
Fast Ends / Break-fast—
Fat Burning Peaks (~12 hrs)—
Autophagy Onset (~16–18 hrs)—
Ketosis Possible (~18–24 hrs)—
Autophagy onset is estimated — actual timing varies by individual, prior meal size, exercise status, and metabolic flexibility. Times shown are approximate thresholds from fasting research (Alirezaei et al. 2010; Mizushima & Komatsu 2011). Consult a healthcare provider before starting extended fasting protocols.

Intermittent Fasting — The Science Behind the Window

Intermittent fasting (IF) is not a diet — it's a timing pattern that determines when you eat, not what. The most studied protocol is 16:8 (16 hours fasting, 8-hour eating window), popularised by Martin Berkhan's LeanGains protocol. The research base has expanded dramatically since 2016, driven partly by Yoshinori Ohsumi's Nobel Prize-winning work on autophagy.

What Happens During a Fast

  • 0–4 hours: Digestion and absorption. Insulin elevated.
  • 4–8 hours: Blood glucose normalises. Glucagon begins mobilising stored glycogen.
  • 8–12 hours: Liver glycogen depletes. Fat oxidation increases. Metabolic flexibility improves.
  • 12–16 hours: Peak fat burning. Growth hormone pulsing increases. Inflammation markers begin declining.
  • 16–18 hours: Autophagy significantly upregulated — cellular cleanup mechanism removes damaged proteins and organelles.
  • 18–24+ hours: Ketone production increases. Deep autophagy. BDNF (brain-derived neurotrophic factor) rises.
FAQ: Will intermittent fasting cause muscle loss?

Not at the durations used in standard IF protocols (16–20 hours), provided protein intake during the eating window is adequate. Research consistently shows that IF with sufficient protein (1.6–2.2g/kg lean body mass) preserves or even increases muscle mass while reducing fat. The slight increase in growth hormone during fasting is actually muscle-protective. Extended fasts (24+ hours) without protein management carry more risk for muscle catabolism.