Hunger
2 / 10
Mood
Calm
Hydration
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Hour 24
Hour 0–4
Digestion winding down
Insulin begins to fall as your last meal is processed (educational estimate).
Hour 4–12
Glycogen drawdown
Your body increasingly uses stored glycogen. Hunger waves are normal.
Hour 12–18
Transition window
Many people report a mood shift and rising clarity.
You are hereHour 18–24
Deeper fat utilization
Ketone production typically increases through this window.
Hour 24–36
Sustained fasted state
Hunger often plateaus. Hydration and sleep matter most.
Hour 36–48
Extended fast (advanced)
Fatigue is common. Listen to your body — break the fast if needed.
Hour 48–72
Advanced education only
Reserved for experienced fasters with prior medical clearance.
All timeline content is educational. Individual experience varies.