What Is 16:8 Fasting? An Intermittent Fasting Schedule

16:8 fasting is a time-restricted eating plan where you consume all your daily calories within an eight-hour window and fast for the remaining 16 hours. It is a popular form of intermittent fasting.

At a glance

Term: 16:8 Fasting
What it is: Time-restricted eating plan
Section: Food and nutrition
Also called: 16/8 intermittent fasting, 16/8 diet
In one line: It’s a way of eating where you only eat during an eight-hour period each day, like from noon to 8 p.m.

What 16:8 Fasting means

16:8 fasting is a pattern of time-restricted eating. The name refers to its structure: you fast for a continuous 16-hour period and have an 8-hour window in which you eat all your meals and snacks for the day. This approach focuses on *when* you eat, not necessarily *what* you eat. Common eating windows include 10 a.m. to 6 p.m. or 12 p.m. to 8 p.m. During the 16-hour fast, you typically consume no calories, though water, black coffee, and unsweetened tea are generally permitted.

The practice is a popular form of intermittent fasting, which involves cycling between periods of eating and voluntary fasting. The underlying idea is to give the body a longer break from the work of digestion. By extending the time between your last meal of one day and the first meal of the next, you give your body a longer period to process nutrients and rest. For some people, aligning the eating window with daylight hours may also better match their body’s natural internal clock, or circadian rhythm.

Many people find that a 16:8 schedule can simplify their day by reducing the number of meals they need to plan and prepare. It can be adapted to different lifestyles; for example, you can shift your eating window to accommodate a dinner with friends or a specific work schedule. The main adjustment is consolidating your food intake into a shorter period. It’s not a diet in the traditional sense of restricting specific foods, but rather a framework for meal timing.

This eating pattern is not for everyone. The quality of food consumed during the eating window is still a key factor for overall health. A diet high in ultra-processed food is not made healthy by a restricted eating window. People with a history of eating disorders, those who are pregnant or breastfeeding, and individuals with certain medical conditions like diabetes should avoid it or speak with a doctor first. When starting, some people may experience side effects like hunger, headaches, or irritability as their body adjusts.

How to try 16:8 fasting

Choose an 8-hour window that fits your daily routine and social life. Many people find a 12 p.m. to 8 p.m. or 10 a.m. to 6 p.m. window works well.
If a 16-hour fast feels too long at first, start with a shorter fast, like 12 or 14 hours, and gradually increase the duration over several days or weeks.
Drink plenty of water throughout the day, including during your fasting period. Unsweetened tea and black coffee are also good options to help you stay hydrated.
During your eating window, focus on balanced, nutrient-dense meals. Include protein, fiber, and healthy fats to promote satiety and provide steady energy.
Pay attention to your body’s signals. If you feel persistently unwell, dizzy, or overly fatigued, this eating style may not be the right fit for you.

16:8 Fasting vs. similar terms

Compared with	How 16:8 Fasting differs	What the other term means
Calorie Deficit	16:8 fasting is a schedule for when you eat, not a rule about how much you eat.	A calorie deficit is a state where you consume fewer calories than your body uses, which is required for weight loss regardless of your eating schedule.

Common misconceptions

Myth: You can eat anything you want during the 8-hour window. While 16:8 fasting doesn’t restrict specific foods, focusing on nutrient-dense options is still important for health. The quality of your diet matters more than the timing of your meals.
Myth: Fasting for 16 hours is the same as starving yourself. For most healthy adults, a 16-hour fast is a manageable period without food that allows the body to use stored energy. It’s different from prolonged starvation, as you replenish your energy stores daily.
Myth: 16:8 fasting guarantees weight loss. Some people find this schedule helps them naturally reduce their calorie intake, which can lead to weight loss. However, it’s not automatic and still depends on your overall energy balance and food choices.

Related terms

When to bring in a professional

It’s a good idea to talk with a doctor or registered dietitian before making significant changes to your eating patterns.

You have a history of an eating disorder.
You are pregnant, breastfeeding, or trying to conceive.
You have a medical condition, especially diabetes or issues with blood sugar regulation.
You are taking medications that need to be taken with food at specific times of the day.

How this entry was made: drafted with AI assistance from general, widely published definitions, checked in a separate verification pass for invented numbers and claims, and edited by the Millennials Wellness editors. General information only, not medical, financial or legal advice. Last checked October 2026. Our ground rules · Back to the glossary