Intermittent Fasting 101 – The Definitive Beginner’s Guide

What is Intermittent Fasting

Dieting trends have come and gone. Many offer incredible benefits and results, whilst some fail quickly and do not catch on. 

The majority of top trending diets in the modern day are with thanks to the internet and them being tried and tested across the world. Most dieting techniques involve meal plans and exercise routines. One that does not involve either and can be made into a lifestyle as opposed to a boring and unrealistic diet is fasting. In particular, intermittent fasting is one to be mentioned here for its impressive benefits and realistic rules.

Intermittent fasting was the top trending Google fasting method in 2019, increasing by over 10,000% since 2010. It is still one of the world’s most popular diet trends. But, that does not mean it is a new method. In fact, fasting has been around for centuries. It involves fasting and eating windows with no specific meal plan or foods to avoid. For most, it is much more real and easy to integrate into a lifestyle choice.

Today, we will be discussing what exactly intermittent fasting is, the different methods, the amazing health benefits and top tips:

What is Intermittent Fasting?

Many people assume that fasting is in some way, starvation. That assumption is completely incorrect. Starvation is an involuntary and uncontrolled period without food. Whereas fasting is voluntary and controlled. Fasting, especially intermittent fasting, is done for health, religious and spiritual reasons. Understanding how to intermittent fast is essential so that a person does not over fast, lack knowledge of the method or fast for the wrong reasons.

Intermittent fasting is an eating pattern method where mealtimes are restricted. It does not tell you what foods to eat and avoid. Instead, it gives you time periods of eating and not eating. Generally, the meal time cycles you choose provide windows of eating and windows of not eating. 

For example, the most popular 16:8 intermittent fasting method is where a person does not eat for 16 hours of the day and then eats for the other 8 hours. 

The intermittent fasting method has no set duration as there are many ways it can be done. Due to there being numerous methods, there is typically one that can work for everyone and their preferences. 

There are cycle windows such as 16:8, 14:10 and 12:12 or the alternate day method which involves one day of normal eating followed by one day of fasting on repeat. There are also intermittent fasting techniques which involve certain days being calorie restricted or days where you spontaneously skip meals. This guide will tell you about the most popular and effective. 

Many studies show how intermittent fasting can benefit many health concerns such as weight loss, type 2 diabetes, managing blood sugar levels and much more, which will be shared later on in the article.

A multiplicity of physicians recommend the fasting technique as the best and most effective way to lose weight. In a review from Obesity Medicine, more than 76% of the patients used intermittent fasting to lose weight over other, and once more popular, diets. 

The intermittent fasting method is further recommended by one of the most notorious medical journals, The New England Journal of Medicine as they stated it is a technique which promotes the most health benefits. 

Intermittent fasting is in fact a more natural way to eat and has been practiced for centuries. It was once natural for humans to go for periods without food and eat less than 3 meals a day. Therefore, suggesting it is effective and a healthier way to eat for your mind and body.

To understand more about where intermittent fasting came from, here is a bit of history:

History of Intermittent Fasting

Although many may perceive intermittent fasting as a fairly modern diet technique, studies show that it may date back to ancient times. It is a traditional and regimented aspect of many religions. Even though the fasting is for different reasons, religious fasting uses similar techniques to intermittent fasting. 

Fasting dates back in history to the Middle Ages. Here, it was often used due to the result of wars, epidemics and plagues. It was a way to practice being without food for periods of time and was a lesson for rationing. 

Since then, it has been used for centuries as a religious method as fasting is healing for the mind, soul and body.

Today, intermittent fasting is often used for many health reasons from weight loss to gut health, extending your lifespan and mindfulness. There are numerous health benefits offered from intermittent fasting and the benefits that can be offered depends on the type of fast a person chooses.

Humans have fasted for much of their history so in that sense, it is nothing new. However, what is new is the abundance of research into its health benefits and what actually happens to the human body during periods of fasting.

With the historic background of intermittent fasting in mind, here is more of how intermittent fasting works:

How Intermittent Fasting Works

During fasting, your body starts to adjust on a cellular and molecular level due to a change in hormones. When a body is in a fasting state, hormones work to make stored body fat accessible and then the body uses fat as fuel instead of glucose.

Typically, energy comes from glucose intake from foods high in carbohydrates like grains, legumes, starchy vegetables and wheat products. When the body has been fasting for over 12 hours and there is no longer any glucose to use as fuel, the body looks for other sources of fuel. That secondary source is from stored fat. 

When the body uses fat as fuel, this encourages fat loss and in turn, weight loss. Fat burning is excelled during fasting and is one of the key benefits.

Your body also goes through a repairing process when fasting. Cells begin to regenerate and repair from previous food intake and exercise. This is better known as autophagy and is the process where old cells digest, diminish and then renew. Studies show how autophagy is a natural way for the body to remove dysfunctional cells and replace them with healthier cells full of protein.

A few other processes the body goes through when fasting include:

  • Insulin balance: During fasting, the body sees huge changes in insulin. Lack of food and giving the body time to digest food helps improve insulin sensitivity and reduces insulin levels. Studies show how lower insulin levels help stored fat be more accessible, which is known as fat burning. Fat burning encourages weight loss and improves a person’s ability to maintain a healthier weight, fat mass and BMI. This process is also very beneficial for diabetic patients, especially those who have type 2 diabetes as insulin sensitivity is a huge issue.
  • Human Growth Hormones (HGH) Increase: Fasting enhances the growth of hormones and during this time, human growth hormones increase exponentially. Research demonstrates how the process of excelled hormone secretion contributes to numerous health benefits such as weight loss, fat burning and muscle gain. 
  • Enhances Gene Expression: Many studies have shown how fasting can cause gene expression. This process is where changes in the genes reduce the risk of developing health conditions, such as cancer and brain aging. Gene expression therefore has benefits of life longevity and protects the body against disease and illness. 

The changes in hormones and the enhancement of cellular repair are the key reasons why intermittent fasting has many health benefits.

Here are 5 of the most popular and effective methods of intermittent fasting to get you started:

5 Popular Intermittent Fasting Methods

Intermittent fasting involves more than just one fasting method. There are many ways in which it can be done. All methods have different effects on the body, fasting cycles, meal routines and health benefits. 

As there are so many, more than just the six mentioned below, there can be an intermittent fasting method that works for everyone. Most will benefit from trying a few different ones to understand what will work best for you.

All intermittent fasts include not eating for a certain period of that time. Typically, in the window where you do not eat, water and calorie free drinks such as black tea and coffee are allowed. 

Click here to see all the Benefits of Intermittent Fasting

Here are the 5 popular intermittent fasting methods:

1 – 16:8: The Time Restricted Eating Method

The time restricted eating method is one of the most commonly used today. It seems to be the most lifestyle friendly and easiest to follow as it can be done everyday or every other day. 

The most popular time restricted eating intermittent fast is 16:8 which simply means a person fasts for 16 hours and eats in the remaining 8 hours. It can be as simple as not eating anything after dinner and skipping breakfast.

During the timed fast, you can drink calorie free drinks such as water, black tea and black coffee as it can help reduce hunger. However, no food or calories are allowed. It is good for your energy levels to stay hydrated throughout the fast so choose water over dehydrating options as and when you can.

It is important to not overeat when you break your fast and throughout your eating window. the overconsumption of food will not allow a person to attain the health benefits, especially if they are seeking weight loss. 

The idea of a smaller window to eat means a person will probably eat 2 meals a day and a snack as opposed to 3 meals a day. Those 2 meals may typically be bigger in size but should always be nutritious if you wish to reap the benefits. The same goes for if you want the fast to be effective.

The alternate time restricted eating methods, which are ratioed like 16:8, include 12:12 and 14:10. The first number dictates the hours you do not eat for then, the latter indicates the window you should use to eat. 

You can choose what times to stop and start eating. For example, you can stop eating at 8.p.m and begin again at 12.p.m the next day for the 16 hour fast. This then means you can eat for 8 hours between 12.p.m and 8.p.m. Or, you can stop at 5.p.m and start eating again at 9am the next day. It is totally up to the person, their preference and lifestyle. So long as you stick to the fasting window, you will successfully be completing the time restricted eating period. 

Good to know : you can combine Ketogenic Diet and Intermittent Fasting 16:8 for better weight loss results

2 – 5:2: The Twice A Week Method

Another popular method of intermittent fasting is the 5:2 diet, sometimes referred to as the twice a week fasting method. This involves fasting/calorie restricting for 2 days of the week. Typically, the 2 fasting days should expect a person to eat around 500 to 600 calories. This should be two small meals of 250 to 300 calories each as opposed to one meal. Eating two smaller meals will reduce fatigue that may occur. 

For the remaining 5 days of the week, a person can consume their recommended calorie amount and should stick to nutritionally balanced meals to avoid excess eating.

If a person is choosing the 5:2 diet for weight loss, or any intermittent fasting method, they should avoid eating excess calories to avert gaining weight. 

Scientific research shows how intermittent fasting techniques, like the 5:2 method, can be very beneficial for weight loss and gut health. Methods like these are shown to be sustainable and effective, even more so when the meals you do consume are nutritiously balanced.

3 – Eat Stop Eat: The 24 Hour/Water Method

The ‘eat stop eat’ intermittent fasting method may be considered the hardest. It involves 24 hour of complete fasting with only water allowed. 

Typically, most people fast from dinner one day to dinner time the following day, which means the person would complete an entire 24 hours of fasting. However, the 24 hour fast can be from breakfast to breakfast or lunch to lunch as well.

It is recommended to only do the ‘eat stop eat’ method only once or twice a week and those days can be chosen by the individual. The reason being for a limited amount of days per week is because it can cause extreme side effects such as fatigue, very low energy, irritability and headaches.

During the fast, calorie free drinks are allowed such as water, black tea and black coffee to limit hunger. But, no solid foods are to be consumed.

It is often advised to try other intermittent fasting methods first before trying the ‘eat stop eat’ method to avoid extreme side effects and risks.

After the fasting days, a person should return back to their normal eating routine and eat the same amount they would without fasting.

4 – Meal Skipping: The Spontaneous Method

Not all intermittent fasting plans involve fasting for long periods of time. Some methods, like meal skipping, can allow a person to reap some of the amazing health benefits.

The meal skipping method involves spontaneously skipping meals throughout the day. 

Many assume that the human body needs feeding every few hours or every single meal time, but that is not true. However, science proves that human bodies are designed to deal with famine or in other words and in this modern time, meal skipping.

This intermittent fasting method simply involves skipping random meals throughout the week. This allows your digestive system to break down all food consumed properly to aid better digestion.  

Many may find this method easier to begin with as it is easier to fast for a smaller amount of time. If you would like to try the fasting methods which involve longer fasting periods, try starting with the meal skipping technique to ease yourself into it.

5 – Alternate Day Fasting: The Every Other Day Method 

The alternate day fasting method involves modified fasting every other day

For some, the fasting day involves 24 hours of fasting and for others, they allow themselves to consume up to 500 calories. The time restricted eating windows such as 16:8 can work here too. 

For example, Monday, Wednesday, Friday and Sunday will be days where the person eats their normal meals and calorie intake. The remaining days will be focused on a 24 hour fast or calorie restrictions. 

Studies show that this method does work but is less effective for weight control and reducing blood sugar level and cholesterol than others. 

Most methods involve restricting calorie intake which typically results in weight loss. However, it is important to remember to not overcompensate for the loss of calories during windows of eating otherwise the results will not be as evident.

Those who choose intermittent fasting find that the time restricted eating method of 16:8 to be the most effective and beneficial for weight loss and more. 

With there being several effective intermittent fasting methods to choose from, you may be wondering what the health benefits are:

The 7 Health Benefits of Intermittent Fasting

Many studies have found that intermittent fasting has very powerful health benefits. Whilst not all are 100% conclusive, these benefits have all demonstrated to be a result of intermittent fasting methods. 

Here are the top ways intermittent fasting can provide health benefits:

Encourages Weight Loss

The number one benefit of intermittent fasting is weight loss. Whilst most diets involve calorie restricting as their top priority, the main reason for weight loss here is due to intermittent fasting increasing fat burning. 

Due to the fasting methods involving periods without food and some periods being calorie restricted, it is a simple way to reduce calorie intake. Studies show that intermittent fasting can reduce body weight, improve body composition and increase metabolism. 

When the body is fasting, energy is provided from stored fat instead of glucose. Typically the human body uses food eaten throughout the day for energy. However, if fasting is in place and no food is being consumed, it has to seek energy elsewhere. The first solution for that is using fat for fuel. When body fat is being used for energy, this encourages fat burning which results in these incredible weight management benefits. 

Scientists review intermittent fasting as a great solution to reduce obesity levels. As there are numerous methods to choose from, science suggests many can benefit from fasting to lose weight, reduce body fat and improve their body composition.

Good to know : If you want to lose weight, you should try the ultimate combo Keto Diet x Intermittent Fasting

Reduces Insulin Resistance

Intermittent fasting methods have great control at reducing insulin resistance, which is ideal for diabetic patients. Insulin rises during eating to help store the food and its nutrients as energy. As there is little space for glucose, the energy which comes from carbohydrates, this is where insulin spikes as it has to overwork in order to store the excess glucose in the liver as fat. The fasting process reduces the need to store fuel as fat which helps the insulin level balance out. 

Studies show reduction in insulin levels from low calorie intake via fasting. The no food window in fasting allows the body to use up stored glucose and fat as energy instead of having an overload, which declines insulin levels and resistance. It is good for your body to have time to digest food and use as much as it can for energy, which is what intermittent fasting promotes.

As well as having benefits for insulin resistance, the study reveals that blood sugar levels can lower by up to 6% with calorie control and up to 31% with intermittent fasting.

Helps Increase Heart Health

Intermittent fasting is known for having many benefits for the heart. Studies demonstrate how patients who partake in intermittent fasting have lower LDL (bad) cholesterol, lower blood sugar levels, reduced triglycerides and insulin resistance which are all contributors to good heart health.

The intermittent fasting has excelled effect on obese or diabetic individuals who are more likely to have poor heart health. However, everyone can attain this benefit. For those who are heart healthy, it can maintain good heart health. 

Reduces Inflammation

Many chronic diseases are caused by inflammation. This includes asthma, arthritis, bowel issues and neurological conditions such as Alzheimer’s disease and dementia.

Studies for intermittent fasting show incredible results for its anti-inflammatory benefits. People who choose intermittent fasting or do it for religious rituals can gain anti-inflammatory benefits from the diet method.

Increases Brain Health 

Intermittent fasting has proved to increase the brain-derived neurotrophic factor hormone, more commonly known as BDNF. It is the diet restrictions that encourages the growth and expansion of the hormone which is sent to the brain. 

This hormone plays a vital role in decreasing the risk of Alzeihmer’s disease, science suggests. The increase of the BDNF hormone that is due to restrictive dieting helps to protect the brain from deteriorating and developing such diseases. 

Science proves that the BDNF hormone plays a vital role in neuronal growth and survival. It is an essential neurotransmitter that enhances memory and learning. This is essential from a young age and to maintain the level of the hormone for good function and growth, the intermittent fasting method can boost it in young and elder adults who partake in the fasting method. 

May Prevent Cancer

Fasting for lengthy periods (more than a few hours/skipping a meal) has shown to have impressive results for preventing certain cancers. In particular, the fasting method plays a role at decreasing tumours that may lead to cancer as well as slowing down the progression of such conditions

So far the testing has mainly been complete on animals, but in most cases animal testing does prove to be true for humans to. 

The testing has not yet signified which cancers it can inhibit or slow down progression of, but tests demonstrate there is potential that intermittent fasting may reverse the detrimental effects of cancerous diseases.

Offers Anti-aging Properties

A test on rats showed that intermittent fasting can extend life span up to 83%. A positive correlation between growth and longer life span was a result of the testing, suggesting the intermittent fasting methods will have a similar effect on adults.

It seems that again, the dietary restrictions played a key role in these tests. The fasting periods with calorie restrictions were the main conclusive reason for the extension of lifespan among the participants. 

Whilst most of the studies have only been tested on animals, the evidence suggests how the results may be similar for humans. More research on humans is yet to be complete. 

Most dieting techniques have some risks and side effects, which is typically due to change in lifestyle and dietary restrictions that the body is shocked into:

Side Effects and Risks Factors of Intermittent Fasting

Intermittent fasting is not for everyone, just like most dieting techniques. With all fasting methods come a few side effects and risks that you should be aware of. For the most part, intermittent fasting is known for having very few risks and is mostly safe. 

Most side effects should be temporary. However, if side effects are consistent, then the method should be stopped and if necessary, the side effects should be seen by a doctor to prevent any health complications. 

With hunger being the main side effect of intermittent fasting due to lack of food for an extended period of time, there are other side effects to be cautious of:

  • Weakness
  • Fatigue
  • Slow reactions
  • Irritability
  • Dehydration

As the fasting methods are very restrictive, it can have more of a detrimental effect on some people more than others. There are a few people/medical conditions which should avoid intermittent fasting:

  • Diabetic patients
  • Anyone with a current or past eating disorder
  • Low blood pressure
  • Underweight individuals
  • Women trying to get pregnant
  • Women with current or past amenorrhea
  • Pregnant or breastfeeding women

Most of those recommended to avoid intermittent fasting seem to be women. The reason for that being because research suggests the fasting methods may not be as effective on women as it is men. Also, fasting techniques have a big impact on hormones and for the most part, it changes them. 

Due to the change in hormones, intermittent fasting can pose dangers for periods, pregnancy and menopause. For these reasons, women should be particularly cautious when fasting.

If you do choose intermittent fasting and want to achieve the best results, here are a few of the top tips:

Tips for the best results

There are many ways you can boost your results with intermittent fasting. Depending on which method you choose, here are the top tips for excelling your results:

  • Avoid sugars and grains: Instead of sugary foods and grains, eat fruits, vegetables, legumes, whole grains, lean proteins, and healthy fats.
  • Avoid snacking by pre-occupying your mind: Snacking is best to avoid. Try and be active during periods you feel you want a snack to build muscle tone and keep your mind active. 
  • Start with an easy intermittent fasting method: Test out the more simple, less restrictive and easy to follow fasting methods before easing into the longer fasts. 
  • Avoid eating at night time: The digestive system has to work extra hard to burn food overnight whilst it’s resting. Try to avoid eating after 8.p.m to let your gut rest and not overwork.

With those tips in mind to achieve the best results, let’s take a look at the pros and cons of intermittent fasting:

Pros and Cons of Intermittent Fasting

Like any diet, there are some things to consider before starting intermittent fasting. Here are the most common pros and cons people need to weigh up:

Helps with weight lossCan interfere with social eating
Has anti-inflammatory benefitsLow energy and productivity
Improves gut and heart healthCan cause people to overeat during eating periods
Reduce the risk of disease and illnessesDigestion Issues
Beneficial for diabetic patientsCan cause stress due to fatigue
Aids better digestionMild side effects whilst the body adjusts

If there are any more concerns or queries, here are the answers to the most frequently asked questions:



The amount of weight a person can lose will depend on a variety of factors such as current weight, diet, lifestyle and exercise routine. Then, how much effort you put into the fasting method will dictate how much weight can be lost. For example, if you do not abide by the dietary restrictions 100%, the results may not be as great.

Studies show how a person can lose between 3 and 8 percent of their body weight after 3 weeks, up to 24 weeks. The majority of participants lost an average of 0.55 pounds per week. 

Can I drink liquid during the fast?

Yes, you can drink liquid during the fast. The drinks must be calorie free which includes water, black tea and black coffee. No calories are allowed during fasting.

Can I take supplements whilst fasting?

Most studies suggest that supplements can be taken during fasting. They are best to consume when the fast is broken during the eating period. It is often encouraged to take supplements when choosing the fast for long periods of time (indefinitely) as some people may experience nutritional deficiencies. 

How long does it take to see results?

Most reports say that it will take several weeks, in most cases around 10 weeks, to see significant results. This can be due to individuals only fasting one or two days per week. Additionally, as there are many methods of intermittent fasting, results vary.

Results will depend on the individual and their chosen fasting method. 

Why am I gaining weight with intermittent fasting?

When a person calorie restricts and consumes less food than normal on a daily basis, weight will be lost. However, if a person chooses to indulge and overeat during the eating window then it is more than likely that the person will gain weight.

During eating windows you should keep meals balanced, avoid overeating and unnecessary snacking. 

Can I intermittent fast everyday?

It is safe to intermittently fasting everyday if you choose certain methods, such as 16:8. After a few weeks the fasting:eating routine will feel natural and your body clock will automatically control appetite better at certain times of the day. 

Some methods of intermittent fasting are not ones you can partake in daily, such as alternate day methods. It is not safe to fast for days on end. The safest method is time restricted eating such as 16:8.

What breaks an intermittent fast?

Anything that contains calories will break an intermittent fast. This can be a calorie drink or any food. 

When you do break the fast, it is advised to consume a small low carbohydrate meal to prevent your blood sugar from spiking.

Can I exercise during fasting?

It is safe to exercise whilst fasting, even if choosing the extended 24 hour fast. As long as your body is energised and you hydrate yourself, your body will cope if you are used to exercising regularly. 

Fasted cardiovascular exercise is commonly associated with excelled fat burning and is a good technique if your goal is to fat burn.

Does intermittent fasting slow down metabolism?

Intermittent fasting has shown to actually increase metabolic rate. During short-term intermittent fasting, such as the methods mentioned above, studies show an increase in metabolism for all participants. 

Metabolism can slow down if the fast is longer than 3 days, which it typically isn’t. However, religious fasting can be for longer than this period and if so, metabolism can slow down here. 

With those thoughts in mind, let’s share our thoughts:


Intermittent fasting has been proven to be outstanding for health and wellbeing. Many of its fasting methods can improve appetite control, blood sugar control, cardiovascular function, and pose many health benefits.

The best and most recommended way to begin your intermittent fasting journey is to start with an easier method, such as meal skipping. When the body adjusts to a simple method, it can then be taken to the next step and the body will be able to cope with longer fasts better. 

Intermittent fasting is great for most people, but not everybody. It is important to be aware of the side effects and risks, especially for those who should avoid fasting due to current or past health conditions. 

It is an impressive weight loss tool and has amazing health benefits. Therefore, for those who work well with intermittent fasting, it is a good idea to sustain the routine and make it part of your lifestyle. 

If you have any more questions or comments, please do share them with us.

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Intermittent Fasting 101
