Fasting protocol comparison

16:8 is the most widely practised intermittent fasting protocol — a 16-hour fast with an 8-hour eating window. 18:6, 20:4, and OMAD extend the fast further. 14:10 and 12:12 are gentler entry points. 5:2 alternates normal days with two low-calorie days per week.

Compare the most common intermittent fasting schedules side by side. Each protocol has a different fasting window, eating window, and level of difficulty — choose the one that fits your lifestyle.

Protocol	Fast	Eating window	Summary	Start
16:8	16h	8h	A 16-hour fast with an 8-hour eating window — the most widely practised intermittent fasting schedule.	Start 16:8 timer
18:6	18h	6h	An 18-hour fast with a 6-hour eating window — a step up in intensity from 16:8.	Start 18:6 timer
20:4	20h	4h	A 20-hour fast with a 4-hour eating window — an advanced protocol sometimes called the Warrior Diet.	Start 20:4 timer
14:10	14h	10h	A 14-hour fast with a 10-hour eating window — a gentle entry point into time-restricted eating.	Start 14:10 timer
12:12	12h	12h	A 12-hour fast with a 12-hour eating window — the most approachable form of time-restricted eating.	Start 12:12 timer
OMAD	23h	1h	One Meal a Day — a 23-hour fast with roughly a 1-hour eating window.	Start OMAD timer
5:2	2 days/wk	~500 kcal	Five normal eating days per week with two non-consecutive days of roughly 500–600 kcal intake.	Start 5:2 timer
23:1	23h	1h	A 23-hour fast with a strict 1-hour eating window — closely related to OMAD but with a fixed one-hour limit.	Start 23:1 timer

16:8
A 16-hour fast with an 8-hour eating window — the most widely practised intermittent fasting schedule.
Fast: 16h
Eating window: 8h
18:6
An 18-hour fast with a 6-hour eating window — a step up in intensity from 16:8.
Fast: 18h
Eating window: 6h
20:4
A 20-hour fast with a 4-hour eating window — an advanced protocol sometimes called the Warrior Diet.
Fast: 20h
Eating window: 4h
14:10
A 14-hour fast with a 10-hour eating window — a gentle entry point into time-restricted eating.
Fast: 14h
Eating window: 10h
12:12
A 12-hour fast with a 12-hour eating window — the most approachable form of time-restricted eating.
Fast: 12h
Eating window: 12h
OMAD
One Meal a Day — a 23-hour fast with roughly a 1-hour eating window.
Fast: 23h
Eating window: 1h
5:2
Five normal eating days per week with two non-consecutive days of roughly 500–600 kcal intake.
Fast: 2 days/wk
Eating window: ~500 kcal
23:1
A 23-hour fast with a strict 1-hour eating window — closely related to OMAD but with a fixed one-hour limit.
Fast: 23h
Eating window: 1h

Not sure which window fits your schedule? Use the fasting calculator to find your ideal eating window times.

Fasting protocol comparison

Compare all protocols