Challenge ideas → Health & Diet
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21 Days of 16:8 Fasting
21 days · Health & Diet
Three weeks of 16-hour fasts with an 8-hour eating window.
The gentlest on-ramp to intermittent fasting: eat within an 8-hour window (say 12pm-8pm) and fast the other 16, most of which you're asleep for. Three weeks is long enough for the hunger waves to flatten and the routine to feel normal.
The rules
- Choose a fixed 8-hour eating window and keep it consistent.
- Outside the window: water, black coffee and plain tea only.
- Check the day off when the window closed on time.
Tips from people who finished
- Push breakfast later gradually - 10am, 11am, noon over the first three days.
- Salt in water helps the day-3 headache more than most people expect.
- Social dinner outside the window? Shift the window that day instead of breaking it.
Track it properly
The difference between "trying" this challenge and finishing it is usually a visible calendar. Create yours and you get:
- A 21-day calendar you tick off daily - with streaks and completion stats computed live.
- Achievement badges (day 1, 7-day streak, halfway, finisher…).
- A share link so a friend can watch and keep you honest - see the accountability playbook.
- A printable version for the fridge.