Intermittent Fasting 101 — The Ultimate Beginner’s Guide 2022

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Intermittent fasting has long been a popular way for health enthusiasts to lose weight. The concept—eat for a certain period of the day and fast for the rest—is very appealing in its simplicity. 

Many people believe that intermittent fasting has brain and body benefits that can’t be achieved through other types of diets. 

Here, we will explain what intermittent fasting is, the different methods, how it affects the body, and who should avoid it due to possible side effects. 

By the time we are done, you will have a working knowledge of intermittent fasting and be able to choose what method will work for you.

What is intermittent fasting?

As the word “intermittent” suggests, intermittent fasting consists of periods of fasting and eating. It focuses on when you eat rather than what you eat.

For people who are tired of obsessively monitoring the calories and nutritional quality of every morsel, this can be a welcome change. 

The idea behind fasting goes back to our ancestors’ way of life, which included times when food was scarce. Hunter-gatherers weren’t always able to find food at the same time every day and would sometimes have to go for hours or even days between meals. 

This forced the human body to adapt during lean times, and practicing intermittent fasting activates those same survival instincts. 

Intermittent Fasting Methods

Intermittent fasting can be done in several different ways, allowing each person to customize it to their preferences and needs. Rather than forcing your body to follow a schedule that is unnatural, you can pick the one that makes you feel the best.


One of the most popular approaches to fasting is the 16/8 method. Sometimes called the Leangains protocol, it involves eating during an 8-hour window and then fasting for the remaining 16 hours. 

For example, if you skip breakfast and begin eating at noon, you can eat all you want until 8 pm. Then, you won’t eat anything until noon the next day. 


The 20/4 method operates on the same principle as the 16/8 but with a shorter eating window. Also known as the Warrior Diet, this approach allows you to eat without restriction for 4 hours and fast for 20 hours each day. 

Eat Stop Eat

This more extreme method requires fasting for a full 24 hours once or twice a week. Even though you don’t have to fast every day, you may need a transition period before comfortably fasting for 24 hours.


With the 5:2 method, you only eat 500-600 calories for two days per week. Don’t do it two days in a row, as this can lead to exhaustion and strain on your body. For the other five days, you can eat normally.

OMAD (One Meal A Day)

If you want a more extreme version of the 20/4 method, the OMAD method consists of eating one meal a day and fasting the rest of the time, roughly 23 hours. 

It’s a type of intermittent fasting that may be effective, but not everyone will find it to be sustainable. 

“As food intake goes to zero, the body switches energy inputs from food to stored food (fat). This strategy significantly increases the availability of ‘food’ which is matched by an increase in energy expenditure.”

– Dr. Jason Fung, The Obesity Code

How does intermittent fasting affect your cells and hormones?

The effects of intermittent fasting go beyond numbers on a scale. They occur on a cellular and hormonal level that may dramatically affect your overall health. 

  • Increased Human Growth Hormone

Human growth hormone (HGH) plays a large role in fat loss and muscle gain, and intermittent fasting seems to significantly increase its levels. 

  • Improved Insulin Sensitivity

With greater insulin sensitivity, overall insulin levels drop, which makes it easier to burn stored body fat. It also reduces the risk of diabetes.

  • Cellular Repair

During fasting periods, your cells repair themselves through autophagy, a process where old proteins within the cells are removed. 

  • Gene Expression

Genes involved in the body’s protection from disease and longevity change and improve. 

Meal Timing vs. Diet

Intermittent fasting is based on the timing of your meals rather than the meals themselves. It is not a specific diet. The cyclical nature of the fasting and eating periods encourages the body to maximize its fat burning and health potential. 

What are the health benefits of intermittent fasting?

  • Weight Loss

The cycles of eating and fasting can help reduce weight and body fat without focusing on calorie restriction. Many people naturally consume less due to the eating windows.

  • Reduced Insulin Resistance

Some evidence suggests that intermittent fasting can help lower blood sugar and reduce insulin resistance, which is a key factor in type 2 diabetes.

  • Reduced Inflammation

Inflammation, a driving force behind many chronic diseases, may be reduced by intermittent fasting.

  • Improved Heart Health

Some people have found intermittent fasting may reduce “bad” LDL cholesterol, increasing  the risk of heart disease.

  • Brain Health

Certain brain cells and functions can increase. It is believed that this can possibly prevent Alzheimer’s disease.

  • Anti-Aging

In some studies, scientists found that rats lived longer when subjected to intermittent fasting. 

Despite all the potential for health improvements, more research is needed to validate the effectiveness of this method in humans. 

Who should be careful or avoid intermittent fasting?

Although intermittent fasting seems like a simple approach to weight loss and better health, it is not for everyone. 

  • Those With Preexisting Health Conditions

People who are already underweight or who struggle with eating disorders could damage their health and should talk to their doctors first. Diabetics and those with low blood pressure should also be wary of it.

  • Women

Previous research showed that women had worse blood sugar control after trying it, and it could possibly affect menstrual cycles. Intermittent fasting would not be advised for women who are pregnant or are trying to get pregnant. It’s also not suggested for breastfeeding mothers. 

Women who want to try intermittent fasting should try introducing it very gradually and closely monitor their bodies for any negative effects.

What are the side effects of intermittent fasting?

When drastically changing your eating habits, there are some side effects that can be especially apparent in the beginning. Because of this, people with health conditions such as diabetes or low blood pressure should always consult with their doctor before trying it.

  • Hunger

You will most likely feel hungry if you’re not used to going longer than 4-6 hours without food during the day. As the body and stomach adapts to the new cycle, this sensation may diminish.

  • Weakness

Your body may initially feel weak and drained of energy if it’s used to refueling every few hours. 

  • Brain fog

The same lack of fuel that weakens your body will also slow your mind and make it feel sluggish. 

Final Thoughts

Intermittent fasting is about eating during certain windows of time, not about what you eat. It is based on the idea of how our ancestors survived when they couldn’t find food at regular intervals. Many people believe that it can have health benefits beyond just weight loss. 

However, women and people with health conditions such as diabetes, low blood pressure, and eating disorders should discuss it with their doctors before attempting. Because every person’s body and system is unique, it’s important to keep track of how your body responds to such a drastic change in eating habits. With careful monitoring and your doctor’s approval, intermittent fasting could be another way to optimize your diet and health.

For more details on how to finally live the healthy life you want, we are here to answer your questions and help you succeed!

I’m Marc Dressen, a high-performance coach, who has worked with elite performers, athletes and entrepreneurs for over 25 years.

I am passionate about unlocking the potential of high achievers - finding that hidden 10% that will take individuals to the next level.

My MSc in Sports Science, coupled with my extensive training in neurolinguistic programming and systemic coaching philosophy has allowed me to incorporate the mind and body into a synergistic machine.

My coaching strategy has now developed into a system that I have coined The Apex Approach, a custom framework that incorporates the latest evidence-based techniques such as biohacking, modern science and digital monitoring, to align the mind and body to its optimum potential. I use biomarkers to remotely coach my clients, so they can receive support whenever they need it.