What is Intermittent Fasting?

Published May 17th, 2022 by Chris Riley
Fact Checked by
Erik Rivera

Intermittent fasting is a dietary pattern that cycles between periods of eating and fasting.

It has been gaining popularity in recent years as people, including myself, are beginning to realize the many health benefits it can offer. 

In this article, we will discuss intermittent fasting in detail, including the most popular intermittent fasting methods, the health benefits of intermittent fasting, the effects on the body, and who needs to avoid intermittent fasting to avoid any adverse effects.

What is intermittent fasting?

Intermittent fasting, also known as intermittent energy restriction, is a calorie-restriction diet where you cycle between a fasting period and eating period throughout the day and it has been used more recently as a popular weight loss approach, to improve insulin sensitivity, or for other health purposes.

Historically, fasting has been used as a way to cleanse the body or mind for millennia having been practiced by many of the most popular religions in the world, but intermittent fasting is a more modern approach that has become popular in recent years for certain health benefits.

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What are the most popular intermittent fasting methods?

There are many intermittent fasting methods, but the most popular ones are as follows:

The 16/8 method

The 16/8 method, also called the Leangains protocol, is a form of time-restricted feeding method where you eat all of your meals within an 8-hour period of time and fast for the remaining 16 hours of the day.

Typically, you would avoid eating breakfast and start your first meal at lunchtime, then eat your final meal of the day around dinnertime.

It is one of the most popular fasts because it’s easier to stick to than other methods and still allows you to have some flexibility with your eating schedule.

Similar methods are used in other intermittent diets such as the 14/10 method or the 20/4 method, where you fast for 20 hours and eat only for 4 hours of the day.

The 5:2 diet

When you participate in the 5:2 diet, you eat normally for a feeding period of 5 non-fasting days per week and are on a caloric restriction of 500-600 calories on 2 fasting days.

The 5:2 diet intermittent fasting method is a form of periodic fasting that was popularized by British journalist and doctor, Michael Mosley.

The two days you fast, women are restricted to 500 calories while men are restricted to 600 calories per day. Which days you choose to fast is up to you; however, they must not be back-to-back fasting days.

The Warrior Diet

With the Warrior Diet, you eat small quantities of raw fruits and vegetables during the daytime and then have one large meal around dinnertime.

A former member of the Israeli Special Forces, Ori Hofmekler, invented this diet and it is based on the way our hunter-gatherer ancestors ate, which was in stark contrast to the 3 square meals per day that are typically eaten in modern times.

Alternate-day fasting

Alternate-day fasting is when you are on a regular diet one day and then fast the next day, consuming either no food or very few calories, usually 25% of your normal caloric intake.


The Eat-Stop-Eat intermittent fasting method is when you fast for 24 hours, once or twice per week.

For example, if you finish your last meal on Monday at dinner time, you would not eat again until dinner time on Tuesday.

The spontaneous meal skipping

Just as its name implies, the spontaneous meal skipping intermittent fasting method is more flexible and can be done anytime you spontaneously feel like skipping a meal.

Meal skipping is an effective strategy due to your ability to eat for an extended period of time and not having to change your daily meal frequency too often.

What are the health benefits of intermittent fasting?

There are many beneficial effects associated with intermittent fasting which we will detail below.

Weight loss

Fasting for weight loss is one of the most popular goals of intermittent fasting, and it has been shown to be an effective weight-loss strategy due to the reduction in your calorie intake.

Several studies have shown that intermittent fasting can lead to significant reductions in body weight over periods of up to 6 months.

Another way intermittent fasting helps with losing weight is by increasing your metabolism, which ultimately burns body fat.

Managing blood sugar levels

Intermittent fasting has been shown to be beneficial for managing blood sugar levels. Fasting can help by reducing your insulin resistance, which is when your body doesn’t respond well to the hormone insulin.

When this happens, blood sugar levels can rise dangerously high as your body uses insulin to burn glucose, also called blood sugar, for energy.

Intermittent fasting has been shown to help reduce insulin resistance, lower blood sugar levels, and reduce levels of insulin, and it may even help in preventing type 2 diabetes by causing a reductions in weight and decreasing your body's insulin resistance.

Cardiovascular health

Your heart health may also be improved by intermittent fasting.

One study showed that intermittent fasting helped reduce low-density lipoprotein, or LDL cholesterol as well as total cholesterol and triglycerides.

All of these are risk factors for cardiovascular disease, which is also called heart disease.

Reducing inflammation

The possible reduction of inflammation is another health benefit of intermittent fasting. Intermittent fasting helped to decrease markers of inflammation, such as C-reactive protein (CRP), in overweight and obese participants in one study.

CRP is a protein produced by your liver in response to inflammation.

High levels of CRP have been linked to an increased risk of heart disease and other chronic diseases.

Brain function

Intermittent fasting may also help improve brain function and protect your brain from age-related damage.

Studies have demonstrated that intermittent fasting increased the growth of new nerve cells in rats' brains.

Another study showed that intermittent fasting protected against cognitive decline in mice that were genetically predisposed to develop Alzheimer's disease.

Physical performance

Your physical performance may also be affected by intermittent fasting by allowing you to lose more fat cells and gain more muscle.

A study on mice also showed an increase in endurance while running.

Cancer prevention

Studies in mice have shown intermittent fasting's ability to also possibly prevent cancer and also retard the growth of tumors or certain forms of cancer such as melanoma and breast cancer.

Antiaging properties

Intermittent fasting has also been linked with antiaging properties.

Studies on rats have shown that intermittent fasting increased the life span of rats and protected them against age-related damage to their brains.

Please note no firm conclusions can be found from these studies due to study sizes or the studies being conducted on animals.

More extensive research, human studies, and scientific evidence are needed to prove the health benefits of intermittent fasting. Also, eating healthy food and a having a balanced diet will also help with weight loss effects.

From around the web: intermittent fasting

Reddit - Intermittent Fasting

Reddit - Starting out guide

Pinterest - Intermittent Fasting

Does intermittent fasting have any effect on my body?

Intermittent fasting can have many different effects on your body, depending on the duration and frequency of your fasts.

The most common way intermittent fasting affects your body is by changing your hormone levels and burning fat.

When you intermittent fast, your body is in a fasting state, which means that your insulin levels are lower and your human growth hormone (HGH) levels are higher.

HGH is a fat-burning hormone that produces the metabolic effect of helping you to burn fat for energy. intermittent fasting also changes the way your body burns fat.

When you fast, your body is forced to burn stored fat for energy, which can lead to weight loss.

Are there any side effects of intermittent fasting?

Intermittent fasting is generally considered safe for most people who are healthy and have a healthy diet.

However, there are some potential side effects, such as fatigue, feelings of hunger, low blood sugar levels, and behavioral side effects such a.

If you have certain health conditions, such as diabetes, heart disease, an eating disorder, high blood pressure, or are taking medications, you need to speak to your doctor or health care professional before trying intermittent fasting.

Women who are pregnant or breastfeeding and children also need to avoid intermittent fasting.


Intermittent fasting is a pattern of eating that involves cycles of fasting and feasting.

The most popular intermittent fasting methods are detailed above along with how to follow them.

Following an intermittent fasting diet has been linked with a number of health benefits, including weight loss, reduced inflammation, improved brain function, and increased physical performance among several others.

However, more research is needed to confirm these effects. There are also some potential side effects of intermittent fasting that you need to be aware of before trying it such as fatigue and hunger.

If you have any questions or concerns, speak to your doctor or health care professional before starting an intermittent fasting diet.

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