The Different Types of Intermittent Fasting

There isn’t just one way to practice intermittent fasting. This tile will explore the options to help you choose whats best for you.


There are many different ways to practice intermittent fasting. Most will have defined fasting windows (when you don’t eat) and feeding windows (when you do eat). Others might specify additional calorie restrictions.

Though there are several options to choose from, the right option for you will come down to your personal objectives (e.g. weight loss or other health benefits) and what fits in your life. The great thing about intermittent fasting is the myriad ways it can be adapted to anyone’s lifestyle.

In this tile, we will take a closer look at the main types of intermittent fasting protocols and how to practice them.

Meal Skipping

**Meal Skipping** is exactly what it says on the tin. Meal skipping allows for a bit more flexibility; you can choose which meal(s) you’d like to skip and on which days. This protocol works well for people whose daily schedules vary a lot.

It should be noted that meal skipping is only a way to experiment with your body and to see how it reacts to longer periods of time without eating. Due to the relatively large feeding windows, it’s harder to unlock the true benefits of intermittent fasting with this approach.

This method can be approached in two different ways:

The first is to only eat when you are hungry. For example, if you wake up and you are not hungry yet, instead of following your normal morning pattern, skip breakfast until you feel hungry.

The second will be to choose a meal to skip. Try skipping a meal intentionally once or twice a week to see how your body reacts to hunger and fasting.

Overnight Fast or 12:12

An **overnight fast** is a fast that takes place overnight. Note however, that the duration of your fast is not equal to the number of hours that you are asleep.

This protocol is easiest to follow if the same 12-hour window is used everyday, for example: If you choose to stop eating after dinner by 8 p.m. and then resume eating at 8 a.m. with breakfast the next morning.

Because the fasting window with this protocol is also relatively short, this method also doesn’t truly maximize the advantages of fasting. Autophagy does still happen at the 12-hour mark, but the benefits won’t be as prominent were you to extend the fast for another 4 hours. Additionally, if you’re fasting for weight loss, a smaller fasting window means more time to eat, and it may not be as effective in reducing the number of calories you consume.

Time-Restricted Eating Protocols and 16:8

**Time-restricted eating** simply means that you have fasting windows where you don’t eat and feeding windows where you do. This method allows for a lot of flexibility, as you will be able to set the fasting and eating windows, and how often you repeat the fast in a weekly cycle.

Experts suggest a fasting window of around 14 to 16 hours to enjoy some of the benefits of intermittent fasting. The highly popular **16:8** protocol is one where the fasting window is 16 hours.

This protocol strikes an ideal balance between adherability, as the fasting window is not that long, while still unlocking many health benefits. As with the overnight fast, the hours spent fasting while sleeping are ‘free’ as you’re not awake when you’re hungry!

Other popular time-restricted protocols include **20:4** and **OMAD or One Meal A Day**.

You should note that if you’re eating for the whole 4 hours in, for example, a 20:4 program, you aren’t actually fasted for 20 hours, because food is still in your digestive system. It takes 3-4 hours for the food to go through your system, so while you may be following 20:4, you’re in a fasted state for only 16 hours.

Time-Restricted Eating Protocols – Timing and Tips

A 16:8 fast simply means that you will fast for 16 hours and eat within a **8 hour feeding window**. There are, however, two popular options within this method of fasting, namely early and late intermittent fasting.

In a 16:8 (Early) intermittent fast, you will fast for 16 hours and eat for 8 hours, with no breakfast. It is recommended to eat two meals between 12:00 and 20:00.

In a 16:8 (Late) intermittent fast, you fast for 16 hours and eat for 8 hours, with no dinner. It is recommended to eat two meals between 06:00 and 14:00.

You can, of course, also choose the hours for fasting that best fit your everyday lifestyle. Generally people find the *early* approach easier to follow because it’s generally harder to skip dinner, and dinner is more intimately entwined with the joys and obligations of our social groups.

It can be surprising how much you can eat in just a few hours, so pay attention to not overindulge in this period!

Some studies have shown that breaking a fast with a low glycemic index or even ketogenic meal (one with almost no carbs and lots of fats) can synthetically extend the fasting window and accordingly the derive the benefits of fasting a little longer.

14:10 Fasting

The **14:10** method is an alternative to the 16:8 method for people who might find fasting for 16 hours difficult. This method of fasting is similar to the 16:8 method, but instead of fasting for 16 hours you only fast for 14 hours, and the remaining 10 hours of the day will then be your feeding window. You can eat your usual meals during the 10-hour window, but you can’t consume any calories during a 14-hour fast. However, you are allowed to drink unsweetened tea or coffee, preferably without any milk, and of course, water.

Also similar to the 16:8 method, you can categorize this method into late and early intermittent fasting.

For 14:10 intermittent fasting, you will fast for 14 hours and have a 10-hour window for eating.

With 14:10 early fasting, you will skip breakfast and with 14:10 late fasting, you’ll skip dinner.

These protocols are flexible, so try experimenting with different fasting windows to fit your lifestyle.

The Warrior Diet (20:4 Method)

During the **Warrior Diet**, participants follow a **20-hour fasting window**, with a minimal to zero-calorie intake, and a 4-hour eating window, where they are allowed to eat what they like. The key component of this schedule is timing. The plan is based on the idea that long periods of fasting and short windows of eating lead to optimal health, fitness, and body composition.

The times that you eat are flexible and you can choose your 4-hour eating window based on your personal preference or schedule. But most people save their feast for the evening hours.

This fasting method was developed by health and fitness author *Ori Hofmekler*. He formed the Warrior Diet in 2001. This was after years of observing himself and his colleagues in the Israeli Special Forces.

During your eating window, Hofmekler suggests basing your meals on healthy fats and large portions of protein, specifically dairy protein sources such as cheese and yogurt.

Because there aren’t any modifications to the Warrior Diet, if you deviate off of the 20:4 cycle, you wouldn’t be on the Warrior Diet anymore.

One Meal a Day (OMAD)

**OMAD**, or one meal a day fasting, refers to an intermittent eating cycle where a person fasts for 23 hours in a day, with a **1-hour eating window.**

In terms of intermittent fasting, this is one of the most extreme forms. This is because, in prolonged fasting, your body starts to move from burning calories to using your body fat as fuel. During ketosis, your appetite is suppressed and feelings of hunger start to dissipate. However, in the OMAD diet, before your body starts getting into the rhythm of fasting, you may experience extreme hunger before you enter ketosis, only to start the process again the next day.

This cycling can make OMAD difficult for beginners, and is thus advised for people with more experience fasting.

That being said, this method works **exceptionally well** for losing weight and improving body composition.

Whole-Day Fasting

This method goes by many names, such as **eat-stop-eat fasting**, **24-hour fasting**, and **whole-day fasting**. It involves fasting where your fasting period is essentially 24 hours. This means if you’ve had dinner at 7 p.m. you are only allowed to eat again on the following day, also at 7 p.m. Although, most people fast from breakfast to breakfast or lunch to lunch. This method is flexible since you can choose which 24 hours to fast.

This method of fasting is usually only done once or twice a week. An example of a whole-day fasting schedule is the **6:1 method**, which involves fasting for 1 day and eating normally for 6 days in a week. With this version of intermittent fasting, as with the OMAD method, the side effects can be quite extreme, such as fatigue, headaches, irritability, hunger, and low energy.

The advantage of whole-day fasting, if done for weight loss, is that it’s unlikely to eat an entire day’s worth of calories in one sitting.

The Twice-a-week Method (The 5:2 Diet)

According to some, the **5:2 Diet**, also known as **The Fast Diet**, is currently the most popular intermittent fasting diet. This diet was popularized by British journalist *Michael Mosley*.

This intermittent fasting schedule focuses on restricting your calorie intake to **500-600 calories** for two days a week. During the other five days of the week, you maintain a healthy and normal diet.

You can choose which two fasting days (say, Monday and Wednesday) as long as there is a non-fasting day between them. It’s important to **not overeat on non-fasting days** and to stick to the same amount of food you would normally eat.

Because there are no requirements about which foods to eat but rather when you should eat them, this diet is more of a lifestyle choice.

Many people find this way of eating to be easier to stick to than a traditional calorie-restricted diet.

Alternate-day fasting (ADF)

This approach was popularized by *Krista Varady*, a nutrition professor at the University of Illinois in Chicago. During alternate day fasting, participants alternate between a fasting day and one eating day. In this approach, non-fasting days are normal eating days.

This method is popular for weight loss. In fact, studies found that, in overweight adults, alternate-day fasting significantly reduced body mass index, weight, fat mass, and total cholesterol.

Studies performed by Dr. Varaday and her colleagues found that side effects, like hunger, decreased or subsided completely by week 2 of alternate-day fasting. And the participants started feeling more satisfied with the diet after week four. The downside was that during the eight weeks of the experiment, study participants said that they were never really satiated which can make adhering to this schedule very challenging.

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