How Long Should You Do Intermittent Fasting?

How long you do intermittent fasting daily depends on the fasting method chosen. Most methods are safe for long-term use.
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There are two ways to look at how long to practice intermittent fasting, the daily practice and the long-term program. Different methods restrict either time or calories daily. The method chosen will determine how long one fasts every day. Follow the program for as long as one wishes and feels good. Intermittent fasting can become a permanent part of your routine.

Written by
Jill Lebofsky
15+yr Women's Wellness Expert, Holistic Menopause Support, Intermittent Fasting, Midlife, Essential Oil, Author, Speaker

A few hours? A week? A month? A year? Forever??? Should you even fast daily ?

Unlike diets that you start and stop when you reach your goal weight, intermittent fasting is a way of life that has no endpoint. If you want to know how long to participate in an intermittent fasting program the answer is as long as you want. The non-weight loss benefits such as decreased inflammation (1), anti-aging (2) and increased energy (3) are worth making intermittent fasting a permanent part of your lifestyle.

But there are limitations on how long you should abstain from eating during the daily fasts.

Decide on what you want to achieve with intermittent fasting. Your goal will determine how long you should fast every day and how long you should continue practicing fasting.


Is intermittent fasting hard to do?

Intermittent fasting isn't about monitoring what you eat. It focuses on paying attention to when you eat. There are times of the day or week you are allowed to eat and times you will fast, allowing yourself minimal amounts of food and drink.

Intermittent fasting isn’t hard to do, it is just finding the method that is best for you.

There are different methods of intermittent fasting, all with varying fasting length times, all beneficial. Choose a method that fits best into your schedule and lifestyle and can be maintained long-term.


Daily time-restricted methods of fasting

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These ways of fasting separate the 24-hour day into fasting and feasting periods. There are no caloric or food restrictions during the eating window, although healthier food choices are recommended.

12-hour or overnight fasting 

Half the day you fast, the other half you can eat. It is a good starting point for beginners. Stop eating after dinner, go to sleep, wake up and the fast is over.

14/10 fasting

This is also a good choice for those new to fasting unable to handle longer fasts.

16/8 fasting

This is the most popular time-restricted method for intermittent fasters. Sixteen hours of fasting and 8 hours of eating are allowed.

Warrior diet or OMAD

OMAD stands for "one meal a day." Fasters pick whatever time of day they want to consume one meal for the whole day. A variation is eating all calories for the day in a short 1 to 3-hour period.


This is similar to the OMAD method. One fasts for 24 hours, from one meal to another but not daily, only a few times a week.


Calorie-restricted methods of fasting

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These methods of fasting restrict the number of calories consumed on certain days. On the other days of the week, there are no food intake limitations.

Alternate-Day Fasting (ADF)

Fasting occurs every other day. On non-fasting days, there is no calorie restriction. On fasting days women can do a complete or partial fast, consuming zero to no more than 500 calories.


A variation of ADF, this method is similar except for five days a week you eat whenever and as much as you want and two days a week (they don't need to be consecutive) you either fast all day or consume up to 500 calories.

Intuitive fasting or skipping a meal

The best choice for those who don't want to commit to a set program on a regular basis. Typically, this method is best for advanced fasters. Eat a meal when hungry until feeling full. If it is mealtime and there is no hunger felt, skip the meal.

Prolonged and water fasting

These are more intensive and for the advanced faster only. Longer fasting periods allow the body more time to reach and maintain the states of autophagy and ketosis, beneficial for weight loss, heart and brain health and anti-aging. One only consumes water or small amounts of foods that won’t stop fat-burning for 24 hours up to 3 days. Longer fasts should be conducted under medical supervision.

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How long should you do intermittent fasting?

There is no predetermined intermittent fasting program length. It is an individual's choice based on one's objectives for fasting.

If weight loss is the goal most people start seeing results within 2-3 weeks. But how long it takes to achieve a weight goal is individualized based on many factors including, food choices, time spent in fat-burning mode, fasting consistency, exercise and genetics. Once reaching the ideal weight desired continue intermittent fasting for maintenance with a few small tweaks to ensure no further weight loss.

If choosing intermittent fasting for its health and anti-aging benefits then consider permanently adopting an intermittent fasting lifestyle. There are no negative consequences for living and eating this way long-term. The only exception is prolonged or water fasting. These should be done only periodically.

Many women in our intermittent fasting online community, in addition to all the benefits they are reaping physically and mentally, enjoy the eating freedom of intermittent fasting, getting to choose when and what to eat. They enjoy less time shopping and cooking and more time spent with those they love doing activities they enjoy.


The bottom line

How long should you do intermittent fasting varies depending on one’s long-term goals. There are different methods of intermittent fasting based on either time or calorie restrictions but all intermittent fasting programs besides the longer fasts (more than 24 hours) are safe, effective and beneficial for permanent use.


1.  Matori E, Pulien J, Toni N et al. Inflammation-Induced Alteration of Astrocyte Mitochondrial Dynamics Require Autophagy For Mitochondrial Network Maintenance. Cell Metabolism. 2013; 18(6): 844-859.

2.  Bhoumik, S., Rizvi, S.I. Anti‐aging effects of intermittent fasting: a potential alternative to calorie restriction?. Biologia 76, 2329–2336 (2021).

3.  Templeman, I., Thompson, D., Gonzalez, J. et al. Intermittent fasting, energy balance and associated health outcomes in adults: study protocol for a randomised controlled trial. Trials 19, 86 (2018).

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