All about Intermittent Fasting: 101 Guide for Beginners

Intermittent fasting (IF) is one of the world’s most popular health and fitness topic nowadays. Many people use it to lose weight, improve their health and simplify their lifestyle. A lot of studies show that it can have powerful effects on your body and brain and might even help you live longer.

What Is Intermittent Fasting (IF)?

Intermittent fasting (IF) is an eating pattern which does not specify which foods you should eat but rather when you should eat them. In this respect, we can say that it’s not a diet in the conventional sense but more accurately can be described as an eating pattern. Common methods of intermittent fasting involve 16-hour fasts on a daily basis or fasting for 24 hours, twice per week.

Fasting has been in practice throughout the evolution of the human race. Ancient humans (the hunter-gatherers) didn’t have supermarkets, refrigerators or food available year-round, there were even times when they couldn’t find anything to eat. Which resulted in the evolution of humans to be able to function without food for extended periods of time. In fact, fasting on a regular basis is more natural than always eating 3–4 (or more) meals per day. Fasting is also often done for religious or spiritual reasons, including in Islam, Hinduism, Christianity, Judaism and Buddhism.

Intermittent Fasting Methods

In intermittent fasting, you break up the day or week into eating and fasting periods, during the fasting periods, you eat either little or nothing in the least. Intermittent fasting has several methods. These are the most popular methods:

The 16/8 method 

It is also known as the Leangains protocol. In this, you skip the breakfast and restrict your daily eating period to 8 hours, such as 12–9 p.m. after which you fast for 16 hours in between.


This involves 24 hours fasting, once or twice a week, like not eating from dinner one day until dinner the next day.

The 5:2 diet

In this type of eating pattern, you consume only 500–600 calories on two non-consecutive days of the week but eat normally the other 5 days.

All of these methods should cause weight loss as a result of reducing the calorie intake, but only if you don’t compensate by eating much more during the eating periods. A lot of people find the 16/8 method to be the simplest, most sustainable and easiest to stick to. Thus it is also the most popular.

The backstory on intermittent fasting

Intermittent Fasting (IF) has been around as a weight loss approach for ages, but was highly popularized in 2012 by BBC broadcast journalist Dr Michael Mosley’s TV documentary Eat Fast, Live Longer and book The Fast Diet, followed by the book The 5:2 Diet by Kate Harrison, based on her own experience, and subsequently by the 2016 bestseller The Obesity Code by Dr Jason Fung. IF generated a steady positive buzz as retellings of its effectiveness grew rapidly.

Intermittent Fasting Impact on Cells and Hormones

Several changes happen in your body when you fast on the cellular and molecular level. Like your body adjusts hormone levels to improve the accessibility of stored body fat, the cells initiate important repair processes and change the expression of genes.

Some of the changes that occur in your body when you fast:

Human Growth Hormone (HGH)

The levels of growth hormone increased abruptly, as much as 5 times. This benefits in fat loss and muscle gain. (1*) (2*).


The sensitivity of insulin improves and insulin levels drop greatly. Lower the insulin levels more accessibility to the stored body fat (3*).

Cellular repair

When you fast, your cells initiate cellular repair processes, including autophagy, where cells digest and remove old and dysfunctional proteins built up inside cells (4*)

Gene expression

Genes related to longevity and protection against disease show changes in their functionality(5*).

These cellular and molecular level changes in hormone levels, cell function and gene expression are the reason behind the health benefits of intermittent fasting.

A Very Powerful Weight Loss Tool

Intermittent fasting weight loss
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Generally, people try intermittent fasting for losing weight. Intermittent fasting leads to an automatic reduction in calorie intake by reducing the number of meals you take. It also helps in changing hormone levels to facilitate weight loss. It not only lowers insulin and increasing growth hormone levels but also increases the release of the fat-burning hormone norepinephrine (noradrenaline).

Because of these hormonal changes, short-term fasting may increase your metabolic rate by 3.6–14% (6*). (7*)

Intermittent fasting changes both sides of the calorie equation as it helps you to eat fewer and burn more calories, resulting in weight loss. A 2014 review study found that intermittent fasting can cause 3–8% weight loss over 3–24 weeks, which is a considerable amount, compared to most weight loss studies, it also found that people lost around 4–7% of their waist circumference which indicates a significant loss of harmful belly fat that builds up around your organs and causes disease (8*).

A study also showed that this eating pattern causes less muscle loss than the more standard method of continuous calorie restriction (9*).

However, the main reason behind its success is that it helps you to eat fewer calories on an overall basis and if you binge and eat vast amounts during your eating periods, you’ll not lose any weight in the least.

Intermittent Fasting is Hard. Is it?

Initial studies compared fasting every other day to eating less every day revealed that both worked about equally for weight loss, but the people struggled with the fasting days. So, according to me IF is neither better nor worse than simply eating less, but far more uncomfortable. So, I advise you to just stick with the sensible, plant-based, Mediterranean-style diet.  The effectiveness of Intermittent Fasting (IF) can be increased significantly when combined with a nutritious plant-based diet. (10*)

We have evolved to be in sync with the circadian rhythm (a day/night cycle). Our metabolism is adapted to eating food during day time and sleeping at night-time. In fact, nighttime eating causes a higher risk of obesity, as well as diabetes.

Researchers from the University of Alabama conducted a study with a small group of obese men with prediabetes, which revealed that by just changing the timing of meals, like by eating earlier in the day and extending the overnight fast, the metabolism improved even in people who didn’t lose a single pound.

Intermittent Fasting Health Benefits

health benefits intermittent fasting
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Intermittent fasting can have many powerful benefits for weight control and the health of your body and brain, might even help you live longer.

Few of the main health benefits of intermittent fasting:

Weight loss

Intermittent fasting can help you lose weight as well as belly fat, that too without having to consciously restrict calories (11*).

Insulin resistance

Intermittent fasting can help in reducing insulin resistance by lowering blood sugar by 3–6% and fasting insulin levels by 20–31%, which helps in protecting against type-2 diabetes (12*).


Some studies show that Intermittent Fasting (IF) helps to reduce markers of inflammation which is a key driver of many chronic diseases (13*).

Heart health

Intermittent fasting helps in reducing “bad” LDL cholesterol, blood triglycerides, inflammatory markers, blood sugar and insulin resistance, all these are the risk factors for heart disease (14*).


Some studies on animals suggest that intermittent fasting can help in preventing cancer (15*).

Brain health

Intermittent fasting increases the brain hormone BDNF, which may aid the growth of new nerve cells and also protect against Alzheimer’s disease (16*).


Intermittent fasting can extend lifespan in rats by 36–83% (17*).

Please note: The research is still in its early stages, not only this but many of the studies were small, short-term or conducted in animals. There are still many questions that are yet to be answered in higher quality human studies.

Makes Your Healthy Lifestyle Simpler

“Eating healthy is simple, but hard to maintain.”

One of the major obstacles is the amount of work required to plan for and cook healthy meals.

Intermittent fasting is very popular among the life-hacking crowd, as it helps to make things easier, it eliminates the need to plan, cook or clean up after as many meals which not only improves your health but also simplify your life at the same time.

Who Should Be Careful Or Avoid Intermittent fasting? Should Women Fast?

People who are underweight or have a history of eating disorders, should not fast without consulting with a health professional first. If not then it’ll be downright harmful.

should women fast
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A study evidenced that it improved insulin sensitivity in men but worsened the blood sugar levels in women.

A number of unreliable reports of women whose menstrual period stopped when they started doing Intermittent fasting and went back to normal when they resumed their previous eating pattern. Thus, women should be careful with intermittent fasting and follow special guidelines, like easing into the practice and stopping as soon as they face any problems like amenorrhea (absence of menstruation).

You should avoid intermittent fasting if you have problems with your menstrual cycles, if you’re breastfeeding or if you’re pregnant or are planning to conceive a baby.

Safety and Side Effects

The main side effect of intermittent fasting is hunger, you may feel weakness and your brain might not be able to perform as well as it used to. But on the bright side, these may only be temporary until your body to adapt to the new meal schedule.

Consult your doctor beforehand if you have any medical condition, especially if you have diabetes, have problems with blood sugar regulation, have low blood pressure, take medications, are underweight, have a history of eating disorders, are a woman who is trying to conceive, is a woman with a history of amenorrhea or are pregnant or breastfeeding.

All that being said, intermittent fasting has an outstanding safety profile if you’re healthy and well-nourished overall.

Getting Started with Intermittent Fasting

Most probably you’ve already done many intermittent fasts in your life, if you’ve ever eaten dinner and not eaten until lunch the next day, then you’ve probably already fasted for 16+ hours. Some people instinctively eat this way, because they don’t feel hungry in the morning. A lot of people consider the 16/8 method as the simplest and the most sustainable way of intermittent fasting, so you might want to try this practice first.

If you find it easy and feel good during the fast, then you can try moving on to more advanced fasts like 24-hour fasts for 1–2 times per week (Eat-Stop-Eat) or only eating 500–600 calories for 1–2 days per week. An alternative approach would be to simply fast whenever it’s convenient like simply skip meals from time to time when you’re not hungry or don’t have time to cook. It is not mandatory to follow a structured intermittent fasting plan to stem at least some of the benefits.

Try the different approaches and find something that you can enjoy and doesn’t disturb your schedule.

Should You Try It?

It isn’t something that anyone needs to do. It’s barely one of many lifestyle strategies that help you to improve your health. Eating the right food, exercising and proper sleep are still the most important factors to focus on. If you don’t favour fasting then you can simply do what suits you.

At the end of the day, there ain’t no one-size-fits-all solution when it comes to nutrition as everyone has different tastes and capabilities, different schedule and eating practices, so the best diet for you is the one which you can follow for a long time but to find out which group you belong to you need to experiment. Intermittent Fasting does wonders for many, so, if you feel good in fasting and find it to be a sustainable way of eating, it can be a very powerful tool to lose weight and improve your health.

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