Intermittent Fasting 101: How Often Should You Intermittent Fast?

You’ve probably heard about the many benefits of intermittent fasting, including:

  • weight loss
  • blood sugar management
  • autophagy (the body’s ability to heal itself)

But how often should you intermittent fast to reap these benefits?

In this article, we’ll answer whether or not there is a best frequency based on the most popular ways to do intermittent fasting:

Types of Intermittent Fasting
Other Types of Intermittent Fasting
Fasting Frequency
A Note on Calories and Nutrition


Types of Intermittent Fasting

Intermittent fasting means eating within a certain window of time and then abstaining from food the rest of the time. The most common type of intermittent fasting is:

Fasting Within a Certain Window

When most people mention intermittent fasting, this is usually what they mean.

The most common eating window is eight hours. For example, you might only eat between:

  • 10am and 6pm
  • 11am and 7pm
  • 12pm and 8pm

Outside of those hours, nothing would be consumed. That’s 16 hours of fasting and eight hours of eating each day. This is often referred to as 16/8 intermittent fasting.

Some people will decrease the eating window even further, such as 20/4 or even as lower as 23/1, only eating during one hour a day. Starting with the standard 16/8 is best for most people.

Although this is the most common method, there are other ways of fasting intermittently that work better for some people.

Other Types of Intermittent Fasting

Other types of intermittent fasting include:

  1. Skipping meals each day, such as not having breakfast or lunch and eating a nutritous meal at dinner, then fasting until breakfast the next morning.
  2. Choosing a couple days to fast each week, such as fasting for 24 hours on Monday and Wednesday.
  3. Fat fasting, which means eating only fats for a few days to induce ketosis. This is common with those following the ketogenic diet. Although you’re still eating food during this time, it can be considered an intermittent form of fasting because you’re “fasting” your body of glucose through the very high fat intake.

Now that we understand the amount of time involved with common forms of intermittent fasting, it’s time to talk about frequency. How often can you partake in these forms of fasting?

How Often Should You Do Intermittent Fasting?

As long as your health is good and you fast safely, you can do intermittent fasting as often as you’d like!

To get the most benefit, fasting regularly is recommended. For example, it’s better to make it a weekly thing than just trying it once every three months.

Below are some examples of how to make it work for you.

Fasting Frequency

Many people who intermittent fast in the common fasting window method (16/8, 18/6, etc) do it every day. 

What Does Daily Intermittent Fasting Do

But, you might be wondering, “what if I want to eat out with friends on the weekends and it lands within my fasting window?”

That’s okay — just keep to your regular fasting schedule during the week and be more lenient on the weekends.

If you do the 24-hour fasting method, you might choose to do it 1-2 days per week and eat normally the rest of the week. As long as you’re eating well in between, this method can also be done continuously every week.

Bottom line: there’s really no wrong answer here. Just pay attention to how your body responds to what you’re doing. You might want to:

  • Test your glucose and ketone levels and monitor your glucose-ketone index for changes.
  • Consider your carb intake. Eating lower carb helps reduce any hunger pangs when starting intermittent fasting.
  • Start with the 16/8 window first and make changes from there based on what works for your lifestyle and schedule.

Adjust what you’re doing as needed. Also, keep in mind that life changes can happen, so you might find it’s better to tweak your eating window over time or be a little more lenient at certain periods.

Give yourself time to adjust to the schedule of intermittent fasting too. Some people adjust easily within a few days, while others need a couple weeks to get used to it.

Plus, being on a ketogenic diet makes fasting even easier to do. Fasting shifts the body into burning fat for fuel instead of glucose, but when you continue eating a regular diet in between fasting periods, the body can shift back into using glucose.

By eating a ketogenic diet during “feasting” periods, you can avoid the side effects of shifting in and out of ketosis.

And speaking of diet, there are a couple points to keep in mind:

A Note on Calories and Nutrition

What’s most important with intermittent fasting is that you’re still eating enough calories during your eating windows to support your body.

Eating Too Few Calories for an Extended Period of Time

The great thing about intermittent fasting is that you can still nourish your body in between fasting windows and avoid these problems.

Also, be mindful of what you’re eating in between fasting periods.

Focus on real whole foods so you get the most bang per calorie. This allows you the benefits of fasting while still consuming optimal nutrition.

The key here is to make the benefits of intermittent fasting work for you over the long-term, for your work patterns and lifestyle.

Make Intermittent Fasting Work for You

No one way of fasting is perfect for everyone, but just about any healthy person can benefit from intermittent fasting.

Intermittent fasting is generally safe to do as often as you’d like. Just make sure you’re eating enough nutritious, whole foods in between.

Combining the ketogenic diet with intermittent fasting is a great way to continue the benefits of fasting and fat burning even when you’re eating.

And lastly, don’t be afraid to experiment and find what works best for you!

Dr. Anthony Gustin is a board-certified sports chiropractor, functional medicine practitioner, entrepreneur, podcast host, and founder of Perfect Keto.

After growing his sports rehab and functional medicine clinics to six locations in San Francisco, he shifted his mission to help as many people as possible achieve optimal health and well-being.


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