How the eating window is worked out
Time-restricted eating splits each day into a fasting period and an eating window. Pick your plan and the time of your first meal; the window closes a set number of hours later and the fast runs until the same time the next day.
Last meal = first meal + eating hours
Fast ends = last meal + fasting hours
Common intermittent fasting schedules
| Plan | Fasting | Eating window |
|---|---|---|
| 12:12 | 12 hours | 12 hours |
| 14:10 | 14 hours | 10 hours |
| 16:8 | 16 hours | 8 hours |
| 18:6 | 18 hours | 6 hours |
| 20:4 | 20 hours | 4 hours |
| OMAD (23:1) | 23 hours | 1 hours |
16:8 is the most common starting point. Many people start with 12:12 or 14:10 and lengthen the fast over a few weeks. The 5:2 approach is different: normal eating five days a week and much lower calories on two days, so it isn't a daily window.
Tips for a sustainable schedule
- Put the window where it fits your life, such as around training or family dinners.
- Keep it consistent — the same window most days is easier than a new one every day.
- Eat enough protein inside the window, especially if you lift.
- Water, black coffee and plain tea don't break a fast.
Intermittent fasting isn't right for everyone. If you are pregnant or breastfeeding, under 18, have had an eating disorder, or take medication for diabetes or blood pressure, speak to a doctor first.
Frequently asked questions
What does 16:8 mean?
You fast for 16 hours and eat all your meals within an 8-hour window, for example between 12:00 PM and 8:00 PM, every day.
Can I drink anything while fasting?
Water, black coffee and plain tea are usually fine because they have no calories. Anything with calories, including milk and sugar in drinks, breaks the fast.
Who should not try intermittent fasting?
Talk to a doctor first if you are pregnant or breastfeeding, under 18, have had an eating disorder, or take medication for diabetes or blood pressure. Fasting is a way to organise meals, not a medical treatment.
General fitness information, not medical advice. Results are estimates; check with a doctor or qualified coach before major changes to diet or training. Last reviewed 2026-09-27.