How The 4 Popular Types of Intermittent Fasting Work

How The 4 Popular Types of Intermittent Fasting Work

Intermittent fasting (IF) has gained significant popularity for its potential health benefits and effectiveness in weight management. 

It’s a weight loss approach cycling between periods of eating and fasting. 

Some advocates view intermittent fasting as essential for improved metabolism, long-term weight loss, and longevity.

Note, however, that there are different ways to do it. Various methods can suit individual preferences, depending on your lifestyle. 

In this article, we will explore the four main types of intermittent fasting and how each works to promote health and well-being.

Patience wins 

Intermittent fasting is not a diet in the conventional sense but rather an eating pattern that focuses on when to eat rather than what to eat. 

It involves alternating cycles of fasting and eating, which can range from several hours to days. 

The primary goal is to optimize the body's metabolic processes and promote fat loss while preserving muscle mass.

It may seem difficult to do at first as your body tries to get used to your new eating pattern.

Fortunately, there are different methods you can use to fit it into your schedule. 

Types of Intermittent Fasting

Time-Restricted Fasting

Also known as the Leangains protocol, it involves fasting for 16 hours and restricting eating to an 8-hour window. 

This typically means skipping breakfast and consuming all meals within a specific time frame, between 12 pm to 8 pm for example

The fasting period helps regulate insulin levels and promote fat burning, while the eating window allows for adequate nutrition and energy intake.

You may also start with 14 hours of fasting and restrict eating to a 10-hour window at the beginning. 

Ramp up to a 16:8 hour fasting-eating window when you’re ready, then train yourself to do 18:6 and so on. 

Eventually, you can perform the 23:1 type of time-restricted eating otherwise known as “one-meal-a-day” or OMAD.

Note that the body’s glycogen reserves are usually depleted after 10 to 12 hours of fasting. It starts to rely on fat stores for fuel after that.

The rate typically increases as you fast for longer periods.

5:2 Diet

The 5:2 diet involves eating normally for five days of the week. Calorie intake is then limited to 500 to 600 calories on each of the remaining two days. 

This amount should constitute about 25 percent of your daily calorie needs.

Keep in mind that the caloric requirements a person needs do vary. Factors such as age, metabolic rates, and physical activity, among others, play a significant role.

According to a study, however, men on average need at least 2,500 calories per day. Women, on the other hand, should get around 2,000 calories daily.

In any case, the two fasting days need not be consecutive. They can be spaced out throughout the week, depending on what works for you.

This approach provides flexibility while still offering the benefits of intermittent fasting, such as improved insulin sensitivity and reduced inflammation.


Eat-Stop-Eat is a more extreme form of intermittent fasting that involves fasting for 24 hours once or twice a week. 

During the fasting period, only calorie-free beverages such as water, tea, and coffee are allowed. 

This method promotes fat loss by creating a significant calorie deficit while preserving lean muscle mass.

Note that it is not advisable to do this first if you are new to fasting. Try to work up your tolerance before attempting this method.

Perhaps doing a form of time-restricted fasting is best until you can comfortably manage to go 24 hours without food.

This is essentially doing a slightly extended OMAD method once or twice a week.

Alternate-Day Fasting

Alternate-day fasting alternates between fasting days, where little to no food is consumed, and feast days, where regular eating is allowed. 

This approach can be challenging for some people but offers similar benefits to other forms of intermittent fasting, including weight loss, improved metabolic health, and enhanced longevity.

Alternate-day fasting is similar to the 5:2 diet in terms of calorie consumption on feeding days and fasting days.

Feeding days are likewise limited to 500 to 600 calories or about 25 percent of your recommended daily intake.

Fasting days are on a set schedule however as it must be done on alternate days.

Activating the benefits

Each type of intermittent fasting works by inducing a metabolic state known as ketosis.

This is where the body switches from using glucose as its primary fuel source to burning stored fat for energy. 

It is facilitated by hormonal changes, including increased levels of growth hormone and insulin sensitivity.

The fasting period also triggers autophagy, a cellular repair process that removes damaged components and promotes overall health and longevity. 

Additionally, intermittent fasting helps regulate appetite hormones, leading to reduced calorie intake and improved satiety.

Patience pays dividends

Numerous studies have demonstrated the efficacy of intermittent fasting for weight loss, metabolic health, and disease prevention. 

Research shows that intermittent fasting can: 

  • Lower insulin levels
  • Improve insulin sensitivity, and 
  • Reduce systemic inflammation

All of these are key factors in the development of chronic diseases such as type 2 diabetes and heart disease.

Tips for Success

Intermittent fasting is a versatile and effective dietary approach that offers numerous health benefits, including weight loss, improved metabolic health, and increased longevity. 

To reap the benefits of intermittent fasting, it's essential to approach it mindfully and make sustainable lifestyle changes. 

Start by gradually increasing fasting intervals and experimenting with different methods to find what works best for you. 

Stay hydrated, listen to your body's hunger cues, and focus on nutrient-dense foods during eating windows to support overall health and well-being.

By understanding the various types of intermittent fasting and how they work, individuals can make informed decisions about incorporating this practice into their lifestyles.


Is intermittent fasting suitable for everyone?

While intermittent fasting can be beneficial for many people, it may not be suitable for individuals with certain medical conditions or dietary restrictions. 

It's essential to consult with a healthcare professional before starting any new diet or fasting regimen.

Can I drink water during fasting periods?

Yes, staying hydrated is crucial during fasting periods. 

Water, plain herbal tea, and plain black coffee are all acceptable beverages that can help curb hunger and support overall well-being. It will not break your fast.

Will intermittent fasting slow down my metabolism?

Contrary to popular belief, intermittent fasting has been shown to have minimal effects on metabolism and may even increase metabolic rate over time.

How long does it take to see results from intermittent fasting?

Results can vary depending on individual factors such as age, metabolism, and activity level. 

Some people may notice changes within a few weeks, while others may take longer to experience noticeable effects.

Can I exercise while fasting?

Yes, exercising during fasting periods is generally safe and can even enhance the benefits of intermittent fasting by promoting fat-burning and improving metabolic health.


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