Comparison
Intermittent fasting schedules compared
16:8, 18:6, 20:4, OMAD, 14:10, 5:2: the names sound very different, but they all pull the same lever. Here is how each schedule works, who it suits, and how to pick the one that fits your week.
Every intermittent fasting schedule is built from the same two ideas: how long you fast, and how often. That is it. A name like 16:8 or 5:2 is just shorthand for a particular combination of those two settings. Once you see that, the long list of methods stops being confusing and starts looking like a single dial you can turn up or down.
Most daily schedules describe a single 24-hour day, split into fasting hours and eating hours. The 16:8 in 16:8 intermittent fasting means 16 hours fasting and an 8-hour eating window. Push the window narrower and you get 18:6 or 20:4. Shrink it all the way to a single meal and you have OMAD. A few schedules work across the week instead, like 5:2, where the unit is days rather than hours. Different framing, same lever.
The best fasting schedule is the one you can repeat without dreading it. A gentle window you keep for months beats an aggressive one you quit in a week. Fit the schedule to your life, not your life to the schedule.
The daily window schedules
These are the everyday methods. You fast and eat within the same 24 hours, every day, and the only thing that changes from one method to the next is how wide the eating window is. The narrower the window, the more of the day you spend fasted, and the more demanding the pattern becomes.
16:8: the popular default
16:8 means a 16-hour fast and an 8-hour eating window, for example eating only between noon and 8 pm. Because most of the fast happens while you sleep, it rarely feels as hard as the number sounds. You typically skip breakfast, eat lunch, an afternoon snack and dinner, then close the kitchen for the evening and night.
Who it suits: almost everyone. It is the standard starting point, flexible enough to work around a job, family meals and training.
Main trade-off: it is the gentlest of the daily windows, so if your goal is to spend long stretches deeply fasted, 16:8 sits at the mild end of that curve.
18:6: a tighter window
18:6 narrows the eating window to six hours, for example 1 pm to 7 pm. It is a natural next step once 16:8 feels easy. The extra two fasted hours are noticeable but not dramatic, and most people fold them in by pushing their first meal a little later.
Who it suits: people who have run 16:8 comfortably for a few weeks and want a slightly longer daily fast without committing to one meal a day.
Main trade-off: a six-hour window can make three full meals feel cramped, so you often settle into two solid meals plus a snack.
20:4: the Warrior pattern
20:4 leaves a four-hour eating window after a 20-hour fast. It is sometimes called the Warrior pattern, which traditionally pairs a 20-hour fast (with small amounts of light eating allowed by some versions) with one large evening meal inside the short window. In its stricter form you simply eat within four hours and fast the rest.
Who it suits: experienced fasters who like structure and find that a single concentrated eating block fits their day better than grazing.
Main trade-off: getting enough protein and nutrients into four hours takes planning, and the long fast is harder to sustain on heavy training days.
OMAD: one meal a day (23:1)
OMAD is one meal a day, which works out to roughly a 23-hour fast and a one-hour eating window. Everything you eat for the day lands in a single sitting. It is the simplest schedule to describe and one of the more demanding to live with, because there is no second meal to fall back on if the first one is light.
Who it suits: seasoned fasters who value simplicity and find that one large, well-built meal keeps them satisfied. We cover the details, including how to build that meal, in OMAD explained.
Main trade-off: hitting your full daily nutrition in one meal is hard, and the long fast leaves little room for error on energy or social eating.
14:10: a gentle on-ramp
14:10 flips the difficulty the other way. A 14-hour fast and a 10-hour eating window is the easiest pattern to start with, and for many beginners it is barely a change from how they already eat. Finish dinner at 8 pm, eat again at 10 am, and you are done.
Who it suits: complete beginners, anyone easing in carefully, or people who want the routine of fasting without a demanding window. It pairs well with our beginners guide.
Main trade-off: the fast is short, so the metabolic shift toward fat-burning is milder than with longer windows. As an on-ramp, that is the point, not a flaw.
The weekly schedules
These methods change the unit from hours to days. Instead of fasting part of every day, you eat normally on most days and restrict heavily on a couple of them. The week, not the day, is the cycle.
5:2: two low-calorie days
On 5:2 you eat normally for five days and keep two non-consecutive days to around 500 to 600 calories. The two light days are spaced out, for example Monday and Thursday, so you are never restricting two days in a row. Outside those days there is no fasting window to track at all.
Who it suits: people who dislike daily restriction and would rather concentrate the effort into two manageable days. The five normal days make it socially easy.
Main trade-off: the low-calorie days are genuinely low, and counting calories on those days is part of the deal, so it asks for more tracking than a simple daily window.
Alternate-day fasting
Alternate-day fasting alternates a normal eating day with a fasting or very-low-calorie day, roughly every other day. It is the most advanced pattern on this list and the hardest to sustain, since the restricted days come around far more often than on 5:2. Treat it as a step you grow into, not a starting point, and only after you are comfortable with daily fasting.
Try any schedule, one tap
Temper ships with preset plans for 16:8, 18:6 and OMAD, plus a custom window you can set to any length. A progress ring shows exactly how far into your fast you are. Free, ad-free, and works offline.
How to choose your schedule
With the menu laid out, the real question is which one fits the life you actually live. Four things usually decide it.
Lifestyle and routine. Look at when you naturally feel hungry and when your day has room. If mornings are rushed and you never miss dinner, a window that skips breakfast (16:8 or 18:6) slots in cleanly. If you wake up hungry and prefer to stop eating early, an early window or a gentle 14:10 may suit you better.
Training. Heavy training days are harder to pair with long fasts. If you lift or run seriously, a shorter daily fast like 16:8 leaves more room to fuel and recover than 20:4 or OMAD. You can still fast, you just keep the window wide enough to eat around your sessions.
Social meals. Fasting should not turn every dinner into a negotiation. If your social life runs on shared meals, a flexible daily window or 5:2, where five days are completely normal, protects those moments. The schedule you can keep around other people is the one that lasts.
Experience level. Start gentler than you think you need to. Most people who quit fasting did not pick the wrong method, they picked too aggressive a version too fast. Begin at 14:10 or 16:8, let it become routine, then tighten the window only if you want to. Our guide to starting intermittent fasting walks through that on-ramp week by week.
How to pick your schedule
If you want a simple decision path, follow these five steps in order:
- Start gentle. Begin with 14:10 or 16:8 even if you think you can handle more. The goal of week one is to prove the habit, not to push the limit.
- Match it to your day. Place the eating window where your real meals and hunger already are, around work, family and training, not against them.
- Watch your energy and sleep. Give it a week or two. Steady energy and decent sleep mean the schedule fits. Persistent fatigue, poor sleep or constant preoccupation with food mean it is too aggressive.
- Adjust one step at a time. If it feels easy and you want more, tighten the window by an hour or two, not by jumping from 16:8 straight to OMAD. If it feels too hard, widen it back out.
- Stay consistent. Pick the version you can repeat on a normal week and keep it. Consistency over months matters far more than which exact ratio you chose.
Who should be cautious
No fasting schedule, gentle or strict, is right for everyone. If you are pregnant or breastfeeding, under 18, have a history of disordered eating, are underweight, or have diabetes or take medication that affects blood sugar, talk to a doctor before changing your eating pattern. The longer and stricter schedules, like 20:4, OMAD and alternate-day fasting, raise the stakes further. Fasting can interact with medication timing and blood sugar in ways that need real medical input, not an article.
For most healthy adults, trying a daily window is low-stakes. You are moving your meals closer together, nothing more. If a schedule does not suit you, you change it or stop, and nothing is lost.
Where to go next
If you are still deciding, the simplest move is to start with the default and adjust from there. Read what 16:8 intermittent fasting is for the full picture of the most popular window, or our beginners guide if you have never fasted before. When you are ready to commit to a routine, the starting guide turns the schedule you picked into a week-by-week plan.