Intermittent Fasting Schedule and Rules

This article provides you with an intermittent fasting schedule and some rules to follow so you can reap the benefits of this widely known weight management technique. 

Last Updated: July 29, 2019

Each and every week a new way of eating seems to pop up, promising a surefire way to boost health and lose weight — often with very little effort involved on your part

Now, while most of you are undoubtedly skeptical of these claims (and if something sounds too good to be true, then you should be), it can become quite challenging to sort through all this misinformation and actually find something that works.

Like intermittent fasting, for example.

Intermittent fasting has become incredibly popular among the health-conscious public over the last year or so.  Numerous, vocal supporters have come out of the woodwork, claiming that this way of eating is a great tool for improving health and promoting fat-specific weight loss.  But are all those claims just nonsense?

Let’s turn to the evidence, starting with: what is intermittent fasting, anyway?

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What is Intermittent Fasting?

Intermittent fasting describes periods of eating that are broken up by periods of fasting, with fasting being a period of time where you abstain from food.  

Although this may sound like a somewhat odd or unnatural dietary approach, fasting is a natural part of human biology.  You fast each and every night while you sleep.  For the entire night, you abstain from eating and then you break your fast with breakfast (break fast… get it?) the following day.

There are many ways to do intermittent fasting but they all have one trait in common: not consuming any food for at least 12 hours.

What are the Types of Intermittent Fasting?

Alarm clock on a windowsill

There are three main types of intermittent fasting diets:

  • time-restricted feeding
  • alternate-day fasting
  • periodic fasting

Time-Restricted Feeding

Time-restricted feeding is what most people mean when they say “intermittent fasting”.

It is a method of intermittent fasting where you cycle between periods of eating and fasting within a single day.  

This is most commonly done by setting:

  • an 8-hour eating “window” (in which you consume all calories for the day) followed by a 16 hour period of fasting or
  • a 4-hour eating “window” followed by a 20 hour fast

Although a 16-20 hour fast may sound difficult at first, it’s not as bad as it seems.  

Since we all fast overnight (during sleep), time-restricted feeding just requires extending this nighttime fasting period.  This can be done by:

  • skipping breakfast (making the first meal of the day around 1-2 pm) or
  • skipping dinner (making the last meal of a day around 1-2 pm)

Alternate (or Alternative) Day Fasting

Alternate day fasting is quickly becoming one of the most popular methods of intermittent fasting, almost entirely due to the introduction of the 5:2 diet into the mainstream health world.

Alternate day fasting describes a process where you either:

  • abstain from eating entirely on two (non-consecutive) days of the week or
  • limit your energy consumption to less than 500 calories (for women) or 600 calories (for men) on two (non-consecutive) days of the week 

This pretty much means five days per week of eating normally and two days of eating either nothing or one small meal each day.


Learn More About the 5:2 Diet Here

Periodic Fasting

Periodic fasting is what most think of when they hear the word “fasting”.  It describes fasting periods that last multiple, consecutive days.

Periodic fasting can be separated into two clear categories:

  • short term periodic fasting (STPF), which describes fasts that last less than three consecutive days
  • long term periodic fasting (LTPF), which describes fasts that last longer than three consecutive days

What are the Health Benefits of Intermittent Fasting?

Now, you have to be wondering: “Does not eating for 16 hours, or even several days, really do good things for your body as supporters claim?”

The short answer is: yes.

Studies show that intermittent fasting does have a variety of health benefits!

During a period of fasting, there are two large, beneficial hormonal changes which provide a host of metabolic improvements.  These key changes are:

Decreased Insulin Levels

Insulin is known as an “energy storage hormone”.  It assists the body in shuttling protein, glucose, and fats from the bloodstream into the body’s cells. There, they can be stored until they are needed for energy.  

When insulin secretion is reduced during periods of fasting, the body gains easy access to fat for energy.  As a result, your ability to break down and use fat for energy is improved, helping you lose fat-specific weight each day you fast.

Related: The Ketogenic Diet and Fat Loss

Long-term intermittent fasting may have additional benefits by inducing chronically reduced insulin secretion, which can increase the body’s sensitivity to insulin and reduce the risk of developing:

  • metabolic diseases (such as diabetes and obesity)
  • cardiovascular disease
  • dementia

Increased Human Growth Hormone

Human growth hormone plays important roles in both fat metabolism, and the development of new muscle tissue.  

Increasing its secretion by fasting at regular intervals may be able to improve your body composition (i.e. increase the percent of your body weight made up of healthy, fat-free tissue) by helping you build new muscle.

Are the Health Benefits of Time-Restricted Feeding, Alternate Day Fasting, and Periodic Fasting Different?

All intermittent fasting types appear to have similar hormonal benefits.  Periodic fasting, however, may have some additional health benefits, as well.

Data, primarily from animal studies, suggests that short periodic fasts (2 days) may be able to:

It is important to note that even despite early signs (and a lot of anecdotal evidence) further human research is needed to fully support these claims for periodic fasts.

Rules of Intermittent Fasting

How Do I Do Intermittent Fasting? Rules of Intermittent Fasting

I do get quite a lot of questions about what you can and cannot eat during a fasting period and it isn’t always as cut and dry as you would think.

What Can You Eat or Drink While Intermittent Fasting?

During your fasting window, it is of the utmost importance that you do not consume any calories at all.  As soon as you consume some form of energy, insulin secretion will increase and growth hormone secretion will decrease — essentially eliminating the positive hormonal effects associated with intermittent fasting.  

This means that during your fasting window you can only consume zero-calorie beverages, such as water, black coffee, and green tea.  And you may want to consume them during your fast. Evidence suggests that they may be able to blunt hunger and may make managing your fasting window a bit easier.

Can You Chew Gum During Intermittent Fasting?

Similar to the above, you are more than welcome to chew gum during your fasting period.  As long as it’s calorie-free.  

Can You Drink Water While Intermittent Fasting?


When it comes to your fasting window, drinking water is encouraged.  Not only is water consumption a surefire way to improve health and function, but it may also blunt hunger signals, making it the perfect accompaniment to intermittent fasting.

How Long Should You Do Intermittent Fasting?

How long you stick to an intermittent fasting schedule depends on what type of fasting you are doing.

For those interested in time-restricted feeding or alternate day fasts, you can comfortably use these long-term or even indefinitely.  They are both easy to implement, and, if they suit your personal schedule, they can make up a key component of a healthy lifestyle.

For those interested in periodic fasts, your best bet is to use these intermittently (just once or twice per year).  The number of years you add a periodic fast, though, is totally unrestricted.  You could add them in for your entire lifetime if you wish!  

In fact, because periodic fasting can have such positive impacts on long-term health, this would be an excellent way to maximize the life-long health benefits you reap from fasting!

What’s the Best Intermittent Fasting Schedule?

Bullet journal for organizing a fasting schedule

Given all of this information (and it is quite a lot of information!), you might be unsure as to what intermittent fasting method is best?

Unfortunately, there is no one best fasting method right for everyone.  The best intermittent fasting schedule for you will ultimately come down to your individual goals and preferences.

Here are the best types of intermittent fasting schedules if your goal is:

  • to improve your metabolic health
  • to improve your cellular health

Goal: Protect Your Metabolic Health or Lose Weight

If you want to improve your metabolic health and/or promote weight loss, you will want to consider creating a restricted feeding or alternate-day fasting schedule for yourself.

Time-Restricted Feeding Schedule

Most people seem to find time-restricted feeding easier to implement and, as I mentioned before, it is a great gateway intermittent fasting strategy.

Typically, you will want to stick to a 16 hour fasting period each day.  (Some people do extend their fast to 20 hours but this can become extremely restrictive.)

Regardless of the fasting period you decide on, there are two ways you can set up your time-restricted feeding schedule:

  1. set eating hours
  2. relative eating hours

To create a set eating hours schedule, you simply pick a 4-8 hour window and designate it your “eating window”.  You can only consume food during these hours.

This strategy provides the convenience of knowing exactly when you can eat each day.  But it may be a bit tricky to stick to, as it offers you little flexibility.  And, if you select an arbitrary time-frame, say 8 am to 4 pm, without taking into account when you wake up and when you go to bed, you may end up struggling to only eat in your window.

A relative eating hours schedule can help you avoid some of these difficulties.  In this type of schedule, you set yourself an eating window relative to either waking up or going to bed.  

For example, I typically recommend that my clients fast for 4-6 hours after waking (whenever that is).  Then, they should aim to have their last meal approximately 8 hours after breakfast.  This provides a more than long enough fasts to reap the metabolic benefits, without having to deal with any regimented time periods.

Alternate Day Fasting Schedule

For those who are looking to implement alternate day fasting, I strongly recommend you organize your fasting days on your two busiest days of the week.  While this may sound counterintuitive, the days where you are at your busiest are the days that go the quickest!  That gives you less time to think about being hungry!

I commonly recommend you consume all your calories at dinner on your fast days (i.e. skip breakfast and lunch).  

So, for example, if you put a fast day on Monday, you would stop eating on Sunday night after dinner.  Then, you would eat your next meal at dinner on Monday night.

I like this strategy because it allows you to eat one completely normal meal on fast days, without messing with all the hormonal benefits associated with intermittent fasting.

So, if you were to put it all together, a week of alternate-day fasting may look like this:

  • Monday: Fast day (consume only dinner)
  • Tuesday: Normal day of eating
  • Wednesday: Normal day of eating (stop eating after dinner)
  • Thursday: Fast day (consume only dinner)
  • Friday: Normal day of eating
  • Saturday: Normal day of eating
  • Sunday: Normal day of eating (stop eating after dinner)

Goal: Cellular Rejuvenation

If you are interested in enhancing cellular rejuvenation, you’ll have to put together a periodic fasting schedule for yourself.

Periodic Fasting Schedule

Luckily, a periodic fast of 3-5 days once or twice a year is all you need to see cellular rejuvenation.   

To put together a periodic fasting schedule, you’re going to want to choose two 3-5 day periods (about 6 months apart).  These should be days in which you aren’t going to be doing much.  This is the opportune time to undertake a prolonged fast because the low energy intakes can make normal tasks challenging.

Since periodic fasts are done sporadically, you can add them to a long-term time-restricted or alternate-day fasting schedule.

Take Home Message

Intermittent fasting offers you a way of eating that can enhance health and promote weight loss.  Although its implementation (and the associated hunger) may be uncomfortable at first, it appears fasting is generally a safe and beneficial practice.

For those interested in trying out intermittent fasting, time-restricted feeding is a great place to start.  It is flexible and simple to integrate into your normal, daily life.  For those looking to enhance cell health and regeneration, in addition to reaping metabolic benefits, periodic fasting may be for you.

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Best Books About Intermittent Fasting

Eat Stop Eat Fasting an Exceptional Human Experience The Scientific Approach to Intermittent Fasting


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