16:8 fasting schedule

On a 16:8 fasting schedule you eat all your food within eight hours and go without for the other sixteen, most of them asleep. The only real decision is where the eight hours sit. Put them around the meals you care about, then let the calculator below give your exact times.

Sample 16:8 fasting schedules with real times

Each row starts the 16 hours when the last meal is finished. The next window opens 16 hours later, and it stays open for 8 hours.

Eating window	Last meal finished by	Fast ends (next day)	Meal you drop	Fits
12 pm to 8 pm	8 pm	12 pm	Breakfast	Evening meals with family or friends
10 am to 6 pm	6 pm	10 am	Late supper and evening snacks	A late breakfast and an early dinner
9 am to 5 pm	5 pm	9 am	The evening meal	People who are hungry in the morning
1 pm to 9 pm	9 pm	1 pm	Breakfast and mid-morning snacks	Late risers and late eaters

A sample day on the 12 pm to 8 pm window looks like this:

• 12:00 pm: first meal, with a good portion of protein.
• 3:30 pm: a snack, such as fruit or yoghurt.
• 7:15 pm: last meal, finished by 8 pm.
• 8 pm to 12 pm: water, black coffee or plain tea only.

If you would rather keep breakfast, the 9 am to 5 pm row shifts the fasting hours to the evening and overnight.

16:8 with no breakfast or no dinner?

Skipping breakfast puts the window over lunch and dinner. Skipping the evening meal means you stop eating at 5 or 6 pm instead. Our schedule chooser has three 16:8 windows. It gives 8 am to 4 pm to morning eaters, 11 am to 7 pm for midday, and 12 pm to 8 pm for evening.

Trials have tested both ends of the day. One 12-month trial used 8 am to 4 pm, and a 12-week trial used noon to 8 pm. Neither window beat its comparison group on weight. The small studies that favour an early finish used shorter, 6-hour windows, so they are covered on the 18:6 page.

What trials of 16:8 intermittent fasting found

Three trials put adults on an 8-hour eating window:

Window	Who and how long	What happened
10 am to 6 pm	23 adults with obesity, 12 weeks, compared with a matched earlier group	Weight down about 2.6%; daily intake fell by about 341 kcal with no calorie counting; systolic blood pressure fell by about 7 mm Hg
Noon to 8 pm	116 adults, 12 weeks, no calorie target	No more weight loss than eating three meals through the day
8 am to 4 pm, plus a calorie target	139 adults with obesity, 12 months	8.0 kg lost against 6.3 kg with the calorie target alone; the gap was not significant

So an 8-hour window helps when it leads you to eat less. When calories are equal, it adds little on its own, and human trials point that way, so the evidence is moderate. The blood-pressure fall comes from one small pilot study without a randomised comparison group, so that evidence is early.

Some questions have no 16:8 answer yet. Research in people has not pinned down when autophagy (cell recycling) begins, so a 16-hour fast comes with no autophagy promise. Growth hormone rises during longer fasts, but the study behind that tested fasts of 1 and 5 days, not 16 hours. Fat burning and ketone production pick up once liver glycogen runs low, which in human studies takes anywhere from 12 to 36 hours. A 16-hour fast may get there on some days and not others.

Who 16:8 suits, and who it doesn’t

16:8 tends to suit people who already go about 14 hours overnight without much trouble. That is the point at which our schedule chooser starts suggesting it. It also suits people who are happy with two meals and a snack.

It is a poor fit if you need medical advice before fasting at all. That covers pregnancy, breastfeeding and being under 18. It also covers being frail, type 1 diabetes, and taking insulin or a sulfonylurea. We advise against 16:8 for people who are underweight or who have a current or past eating disorder. If you take a medicine with food, such as metformin, check with your doctor how to place your window.

Stepping up to 16:8, or back down

If you already eat within about 10 hours, push your first meal back by an hour and hold that for seven days. That gives you 15:9. When that feels ordinary, add the last hour. If you are starting from scratch, begin on the 14:10 schedule, which also covers 12:12 as a first step.

Step back to 14:10 if 16:8 leaves you with regular headaches or poor sleep, or if it makes you eat much more in the evening. Women whose periods change or stop should ease off too. Moving the other way, the 18:6 page covers the next two hours.

A realistic first week on 16:8

This plan assumes you finish dinner at 8 pm each day. It is our suggestion, so shift every time by the same amount if your evening runs later.

Days	First meal	Fasting hours	What to watch
1 and 2	11 am	15	Mid-morning hunger; have water or black coffee
3 and 4	12 pm	16	Whether the first meal turns into a very large one
5	12 pm	16	Sleep and energy in the afternoon
6 and 7 (weekend)	12 pm, or 1 pm after a 9 pm dinner	16	Keeping the same times when your routine changes

Expect the scale to move a little in the first days. Glycogen, the carbohydrate stored in your liver and muscles, holds about 3 to 4 grams of water per gram. Using some of it releases that water, so an early drop is not all fat.

Plan protein for the window as well. A 75 kg (165 lb) adult needs at least 60 g a day. If they exercise, the range is about 105 to 150 g. Spread over two meals and a snack, that is roughly 35 to 50 g each time. Our week of sample 16:8 meals puts that protein on a plate.

To keep the times in view, print the week from the schedule template, or start each fast on the fasting timer. Compare 16:8 with every other option on the intermittent fasting schedules hub.