16:8 Intermittent Fasting: Schedule, What to Eat and Results

16:8 intermittent fasting means you eat all your food within 8 hours of the day and fast for the other 16. The most common version is eating from 12 PM to 8 PM, which in practice means skipping breakfast and late-night snacks. During the 16-hour fast you can drink water, black coffee and plain tea.

It is the most popular way to do intermittent fasting because most of the fast happens while you sleep. It can help you lose weight, but mainly by helping you eat less. Large trials have found that 16:8 doesn’t burn more fat than eating the same calories at any time of day. (1) (2) Here is how to set it up, what to eat, and what results to expect.

16:8 Fasting Schedules You Can Use

Pick the window that fits your day and keep it roughly the same every day. Our intermittent fasting calculator shows your exact eating and fasting times, and a daily calorie target, for any start time.

Night shift? Count your “day” from when you wake up. Eat during the first 8 hours of your waking day and fast through the rest, including the hours before you sleep.

How to Start 16:8 Intermittent Fasting

Going from three meals and snacks straight to a 16-hour fast is where most people struggle. A gentler way in:

1. Start with 12 hours. Stop eating after dinner and wait 12 hours until breakfast. Our 12-hour fast guide covers this first step.
2. Add an hour every few days. Push breakfast back by an hour, or finish dinner an hour earlier, until you reach 16 hours.
3. Drink through the morning. Water, black coffee and plain tea take the edge off hunger without breaking the fast.
4. Keep the clock steady. Hunger tends to arrive at the times you usually eat, so a fixed schedule gets easier within a week or two.

Not sure if a drink or supplement counts? Our what breaks a fast tool checks it. Want a longer fast later? See 20:4 intermittent fasting, or compare all the schedules in our fasting protocols.

What to Eat on 16:8

16:8 sets when you eat, not what you eat. Your results still depend on the food. A simple way to build your 2 or 3 meals:

• Protein at every meal: eggs, Greek yogurt, fish, chicken, beans or tofu. It keeps you full and helps you hold on to muscle. Our protein calculator gives you a daily target.
• Plenty of vegetables and fruit for fiber and volume.
• Whole grains and healthy fats (oats, rice, potatoes, olive oil, nuts) in amounts that fit your calories.
• Few ultra-processed snacks and sugary drinks. An 8-hour window still has room for plenty of them.

For your first meal, see what to eat after a 16-hour fast. To split your calories into protein, carbs and fat, use the IF macro calculator.

How Many Calories Should You Eat on 16:8?

To lose weight, eat less than you burn, whatever your window. Start from your daily calorie burn (our TDEE calculator estimates it) and eat about 300 to 500 calories below it. A 500-calorie daily gap adds up to roughly 1 pound a week.

To keep your weight steady, eat about what you burn, just inside 8 hours. For a full walkthrough with examples, read how many calories to eat during 16:8 fasting.

Does 16:8 Work for Weight Loss?

Yes, if it helps you eat less. The fasting window on its own isn’t the active ingredient. Two of the best trials show this:

• The TREAT trial (2020): 116 adults with overweight ate freely from 12 PM to 8 PM, or ate three regular meals, for 12 weeks. The 16:8 group lost 0.94 kg (about 2 lb) and the meal group 0.68 kg; the difference wasn’t meaningful. (1)
• The NEJM trial (2022): 139 adults with obesity all cut their calories for a year; half also ate only between 8 AM and 4 PM. Both groups lost a similar amount: 8.0 kg with the time window, 6.3 kg without, a difference that could be chance. (2)

So why do so many people lose weight on 16:8? Because a shorter window usually means fewer meals and no late-night snacking, and that cuts calories without counting them. Reviews of intermittent fasting find weight loss similar to ordinary calorie cutting. (3) (4) If 16:8 is the easiest way for you to eat less, it is a good choice. If you end up eating the same amount in 8 hours, it won’t do much.

16:8 Results: What to Expect After a Month

With a 500-calorie daily deficit, expect about 1 pound of fat loss a week, so around 4 pounds in the first month. The scale often drops faster in week one, mostly from water and less food in your gut, then settles. If you see nothing after 3 to 4 weeks, you are probably eating about as much as before. Check your calories rather than lengthening the fast.

Does 16:8 Cause Muscle Loss?

It can, if you don’t train and don’t eat enough protein. In the TREAT trial, the 16:8 group lost slightly more lean mass than the regular-meal group. (1) Lift weights two or three times a week and get protein in each meal of your window.

Other Possible Benefits

• Blood sugar and insulin: in a small, tightly controlled trial, men with prediabetes who ate all their food in 6 hours before 3 PM had better insulin sensitivity and blood pressure, even without losing weight. (5) That was an early eating window; a late one, like 12 PM to 8 PM, may not do the same.
• Less snacking: a set window gives you a clear stop time, which many people find easier than counting.
• Simplicity: no foods are banned and there is nothing to buy.

Claims that 16:8 fights cancer or extends lifespan come mostly from animal studies, not from people.

Side Effects and Who Should Not Do 16:8

In the first week or two, hunger, headaches, low energy and irritability are common and usually fade as you adjust. Drink enough water.

Talk to your doctor before trying 16:8 if you:

• Have diabetes, especially if you take insulin or other medication that lowers blood sugar. Fasting raises the risk of low blood sugar (hypoglycemia). (6)
• Are pregnant or breastfeeding
• Are under 18
• Have, or have had, an eating disorder
• Are underweight

16:8 vs Other Fasting Schedules

For a side-by-side of the two most common choices, read 12:12 vs 16:8 intermittent fasting.

FAQs

Is 16:8 a good intermittent fasting schedule?

For most healthy adults it is a good balance: long enough to cut out snacking, short enough to keep up. It isn’t better for fat loss than eating the same calories at other times, so choose it if it suits your routine.

How long does it take for 16:8 to work?

Most people notice the scale moving within 2 to 4 weeks, as long as they are eating less than they burn. The first few days are mostly water weight.

Can I drink coffee during the 16-hour fast?

Yes. Black coffee, plain tea and water are fine. Milk, sugar, creamer and anything with real calories break the fast.

Can I drink diet soda while fasting?

Diet soda has almost no calories, so it doesn’t break the fast in calorie terms. Water, coffee and tea are still the better habit. Check any drink in our what breaks a fast tool.

Can I do 16:8 every day?

Yes, it is designed as a daily routine. Some people take weekends off and still do well; consistency over weeks matters more than any single day.

Does it matter when my 8-hour window starts?

For weight loss, not much: total calories decide that. For blood sugar, an earlier window (finishing by mid-afternoon) did better in a small trial. (5) Pick a time you can stick with.

The Bottom Line

16:8 intermittent fasting means eating within 8 hours and fasting for 16, usually by skipping breakfast. It works for weight loss when it helps you eat less, not because the fast burns extra fat. Build your meals around protein, keep training, ease in from a 12-hour fast, and check with your doctor first if you have diabetes or take blood sugar medication.

References

Fitness Volt is committed to providing our readers with science-based information. We use only credible and peer-reviewed sources to support the information we share in our articles.

1. Lowe DA, Wu N, Rohdin-Bibby L, et al. Effects of Time-Restricted Eating on Weight Loss and Other Metabolic Parameters in Women and Men With Overweight and Obesity: The TREAT Randomized Clinical Trial. JAMA Intern Med. 2020;180(11):1491-1499.
2. Liu D, Huang Y, Huang C, et al. Calorie Restriction with or without Time-Restricted Eating in Weight Loss. N Engl J Med. 2022;386(16):1495-1504.
3. Harvard T.H. Chan School of Public Health. Diet Review: Intermittent Fasting for Weight Loss. The Nutrition Source.
4. Harris L, Hamilton S, Azevedo LB, et al. Intermittent fasting interventions for treatment of overweight and obesity in adults: a systematic review and meta-analysis. JBI Database System Rev Implement Rep. 2018;16(2):507-547.
5. Sutton EF, Beyl R, Early KS, et al. Early Time-Restricted Feeding Improves Insulin Sensitivity, Blood Pressure, and Oxidative Stress Even without Weight Loss in Men with Prediabetes. Cell Metab. 2018;27(6):1212-1221.
6. Corley BT, Carroll RW, Hall RM, et al. Intermittent fasting in Type 2 diabetes mellitus and the risk of hypoglycaemia: a randomized controlled trial. Diabet Med. 2018;35(5):588-594.