The Clearing stage is hours 4-12 of a fast, when insulin drops and your body burns through stored glycogen (the glucose kept in your liver and muscles) for fuel.
What's happening in your body
As the hours pass without food, insulin steadily falls. With less insulin telling the body to store energy, your liver starts breaking down glycogen - its stored form of glucose - to keep blood sugar steady. A typical liver holds roughly 80-120g of glycogen, enough to fuel you for several hours. Because you're drawing down a stored reserve rather than fighting for new fuel, this stage is usually smooth and hunger-free.
Why this stage matters
The Clearing stage overlaps beautifully with sleep. If you finish eating in the early evening, you'll pass most of this stage unconscious - glycogen depleting quietly overnight - and wake up already deep into your fast. This is the single biggest reason a 16:8 fast feels achievable: you sleep through the work.
What your biometrics show
Overnight, your Garmin or Apple Watch usually shows your lowest resting heart rate and rising HRV as your body recovers. Body Battery recharges through the night. FastFlow's Morning Reveal summarizes this overnight recovery when you wake.
What to do during the Clearing stage
- Sleep - this is the ideal stage to pass unconscious
- Wind down with reading or a warm (non-caloric) drink
- Light meditation or a short evening walk before bed
- Keep hydrating - a glass of water before sleep
Frequently asked questions
What is glycogen and why does it matter for fasting?
Glycogen is glucose your body stores in the liver and muscles. In the Clearing stage (hours 4-12), your body burns this stored glycogen for fuel as insulin falls. Depleting it is the step that unlocks fat-burning in the next stages.
Why does overnight fasting feel so easy?
Because most of the Clearing stage happens while you sleep. Your body quietly depletes glycogen overnight, so you wake already 8-10 hours into your fast without feeling hunger.
Can I drink coffee during the Clearing stage?
Yes. Black coffee, plain tea, and water don't contain calories and won't break your fast or interrupt glycogen depletion.