Are There Any Benefits to Intermittent Fasting?

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Introduction – What is Intermittent Fasting?

Many people are already aware of what intermittent fasting is, and they may even be familiar with some of the most common health benefits associate with this particular dietry protocol. However, when it comes to intermittent fasting (IF) there are far more benefits to be had than you might have first thought. Following an IF program can drastically improve ones health both physically and mentally. Not only this; your lifestyle and productivity in general can take a huge upturn as a result.

Just in case you are not aware of what intermittent fasting is, I will briefly give a short overview here. Essentially, intermittent fasting is a protocol in which you abstain from food, and certain fluids for a prolonged period of time. Any food or drink that contains calories and stimulates a metabolic response in the body is avoided for a specific duration of time.

benefits of intermittent fasting

There are many different forms of fasting in which your fasting and feeding windows last for various lengths of time. Some of the most common protocols are;

  • 16-8 – This format is where you don’t eat (or drink calories) for 16 hours, and then you eat all your caloric intake for the day within the 8 hour feeding window before fasting for 16 hours again. This is one of the easiest methods to do begin with when getting started with fasting.
  • 18-6 – With this method, you fast for 18 hours and then eat your daily caloric intake within a 6 hour window.
  • 20-4 (AKA The Warrior Diet) – You can probably guess this one by now! You fast for 20 hours and eat within a 4 hour window. This protocol is a more advanced strategy and it is only best to attempt this once your body is used to fasting.
  • OMAD (One Meal a Day) – Some die hard IF fans consider the OMAD diet the ‘holy grail’ of fasting! With this method you do what it says on the tin. You eat one substantial meal a day. It is true that after about 19 hours of fasting, your body begins to reap some of the more illusive benefits of fasting such as autophagy and other anti-ageing benefits. We will discuss more on this later.

Now we have an understanding of what intermittent fasting is in its various forms, let’s look at the vast array of benefits that can be had as a result of engaging in any one of these forms of fasting. There will be some common ones in the list that you will already be aware of. However, some of them will definitely surprise you I am sure!

Fat Loss

Perhaps on of the most well know benefits of intermittent fasting is fat loss, and this is one of the main reasons that many people decide to begin a fasting program in the first place.

It is true that fasting is more effective than many other diet programs out there including the dreaded calorie restricted eating plan. The question is how?

“How does fasting actually work in terms of fat burning though; and why is it superior to many other methods?”

Calories in vs calories out theory for fat loss that the vast majority of people are familiar with is fundamentally flawed. The theory assumes that all calories are equal. However, we know this not to be true. We can not oversimplify how different foods are processed in the body and the hormonal effect they have.

Most people believe that the only way to lose body fat is to either reduce the amount of calories you take in through food or increase the amount of calories you expend through exercise.

benefits of intermittent fasting

The diagram on the left is a great analogy that depicts how most people view the calories in, calories out theory for fat loss. It is in fact a myth!…Or at least over simplified. There is not one big container in your body that stores calories. In fact, your body doesn’t even really know what a calorie is. In actual fact, weight gain is a two compartment problem. The analogy I am going to share with you now was made popular by the world leading fasting expert Dr Jason Fung. Dr Fung has a great visual way of explaining how the body actually gains and loses weight.

Take a look at the diagram below.

benefits of intermittent fasting

The above picture hows how fat gain is two compartment problem. Whenever you eat a balanced meal, the carbohydrates in that meal are turned into a a form of sugar called Glucose. Imagine that the glucose is stored in the ‘fridge’ and it is really easy to get to and use. Just like when you go to your actual fridge in the kitchen and get a snack. It is quick and convenient. However, there Is limited space in the fridge. So, as you keep eating those 6 meals a day every 3 hours, more of the glucose get pushed into fat cells by the fat storage hormone insulin. So now you have excess glucose energy getting turned into body fat and thus being stored in the ‘freezer’ that you see in the diagram. Imagine that the freezer has a padlock on it and its in the basement. All the food is frozen so before you use it you have to defrost it. So this energy is now harder to get out of storage and use. Our body fat is that metaphorical freezer. For as long as we are eating, we are spiking our insulin and re-filling our ‘fridge’ with energy in the form of glucose. Even worse, the increase in insulin and over abundance of glucose then prevents you from eing able to access your personal ‘freezer’ to burn your stored body fat. This is because there is enough glucose in your short term energy stores to keep you going. As a result, you begin to gain weight. 

The traffic policeman in the diagram represents the Insulin that turns up every time you eat. He/she turns up and stops the flow of energy (body fat in the freezer and glucose in the fridge) between the two compartments.

**calorie restriction means your body will slow its metabolism and increase hunger because your body isn’t aware that it can tap into its own large fat stores. Therefore your body thinks that it is starving. This is why people fall off the wagon and regain the weight with calorie restriction diets.**

Now, lets look at what happens when we abstain from eating and drinking for a prolonged period of time.

  • benefits of intermittent fasting
  • fasting keto chart 1

We can see from the diagram on the top left that once we fast for a prolonged period, the Insulin drops (the traffic cop disappears) which then allows the fridge to deplete of glucose and then the fat is able to be burned as fuel from the ‘fridge’. Notice how now there is a linear flow of energy which is being burned for fuel and burning body fat at the same time.

On the right is an image that shows this process in graph form. Notice how at the consumption of carbohydrates (the main macro nutrient responsible for spiking Insulin) is reduced, fat oxidisation, AKA fat burning increases exponentially. So we can see now how intermittent fasting allows our body to access its own fat stores by depleting the body of glucose and glycogen.

Reduced Hunger

As your body gets accustomed to fasting and you start to burn your own body fat for fuel, you will find that your hunger massively decreases. This is because your body over time becomes what is called fat adapted and also develops metabolic flexibility. The Mitochondria are the bodies ‘power plants’ which are responsible for converting the caloric energy from food into energy that the body and its cells can use. The longer to engage with an intermittent fasting program, the more effective your body becomes at burning fat and the Lipase Enzymes responsible for oxidising fat for energy are up regulated for the job. Because your body is now aware of your fat stores and it ‘knows’ it can tap into this fuel source at any time it needs to, it means that you don’t get as hungry as often and also your metabolism also increases because your body is no knows that there is a larger fuel source available to you, not just the little amount of Glycogen stored in your liver and muscles. In summary, if after about 3 weeks to a month of intermittent fasting you notice that your hunger levels have massively decreased, you have lost a lot of body fat and you feel mentally focused, then you are most likely fat adapted to a certain degree.

In the video below, one of my favourite intermittent fasting experts on YouTube explains fat adaptation and IF further.

Cures Insulin Resistance and Improves Insulin Sensitivity

When a person is carrying excess body fat, this generally means that their body is not as efficient at processing Carbohydrates and sugars. This is often due to the person in question consuming a high Carb/sugar diet over a long period of time. You see, fat gain is a time dependant phenomenon. Consuming a diet that spikes Insulin levels excessively over a prolonged period of time leads to a condition known as Insulin Resistance.

The main job of insulin is to open up liver and fat cells to allow blood Glucose into them after eating a carbohydrate or sugar rich meal. If a person continues to consume foods that spike Insulin thus allowing the excess Glucose to enter the liver cells, then the cells will soon get full and begin to over flow with the sugar from the blood stream. Therefore the pancreas tries to overcompensate for this by secreting even more Insulin. However, because the liver cells are already full, the Glucose is pushed into the fat cells instead and this is how insulin resistance causes obesity.

  • full baloon glucose final

To make this process easier to understand, take a look at the picture above. The inflated balloon represents a liver cell that is overflowing with Glucose due to a carbohydrate and sugar heavy diet. Because this cell is full, more Insulin is released to try to get more Glucose out of the blood stream and into the liver. To much sugar in the blood can be very dangerous to the body. However, because the cell is full the Insulin still can not get any more Glucose into the liver cell and therefore the sugar is pushed into fat cells instead thus making you overweight.

The simple solution to this Insulin Resistance is to abstain from food, or partake in a low carbohydrate and sugar free diet for a period of time. This allows the body to burn off the stored Glucose in the liver cells and then once that has been burned off the cells will respond normally to Insulin again. This is called Insulin Sensitivity. The wonderful byproduct of all of this is that you burn excess body fat too!

Improved Gut Health

benefits of intermittent fasting

Digestion is a very energy intensive process for the body. Fasting gives a chance for the gut to rest, and cleanse itsself. Not only this, but a study from 2014 discovered that fasting promotes Bacterial Clearance.

The image below shows the title of the study, and you can click on the link below the image and checkout the study for yourself if you are a massive science fan and want to know the entire details of what biological processes took place. In summary, the research found that when mice were put through alternate day fasting they were able to clear Salmonella twice as fast as the non-fasted mice. The bacteria just passed through the intestines and was not absorbed into the body. The fact that is study was performed on mice rather than human subjects does not really discredit the research too much. The reason that researchers use mice in studies like this is that they know the the results are pretty much transferable onto humans. So it’s all good news for your body and its immune system if you do intermittent fasting on a regular basis. You inner workings are going to be much healthier, and your gut will fight off bad bacteria much more efficiently.

benefits of intermittent fastingsource

Not only this, but the process of intermittent fasting also promotes the growth of good bacteria. The stress (good stress) that IF puts on your gut causes the immune system to up its game and thus more good bacteria is colonised. In turn this causes:

  • Better resistance to bad bacteria
  • Improve symptoms of IBS
  • Cures acid reflux
  • Improves indigestion
  • Regulates bowel movements
  • Many more….

Good for Heart Health and the Cardiovascular System

benefits of intermittent fasting

Intermittent fasting is very effective for reducing the risk of cardiovascular disease, heart attack an other related health issues.

It was commonly believed that an over abundance of so called LDL “bad” cholesterol is was the primary cause of heart attacks and cardiovascular disease through a diet that was high in fats. However, this simply is not the case. In fact LDL Cholesterol are essential to the body’s ability to function. Cholesterol is responsible for making hormones such as testosterone as well as many other essential functions and Cholesterol is produced by nesrly every single cell in your body. You NEED Cholesterol to survive! In fact, over 75% of cholesterol is made by your body, not ingested through your diet.

“If Cholesterol is really that bad for you then why is 75% of your total Cholesterol made ‘in house’ by your own body?”


benefits of intermittent fasting

It is in fact the oxidative stress that an over abundance of Glucose in your body has on your LDL Cholesterol and also on your arterial walls that cause Cardiovascular disease and heart attacks.

In simplistic terms, what happens is if you consume too much sugar or carbohydrates over a long period of time is that inflammation and cracks start to appear in the walls or your arteries. As a result, the LDL Cholesterol turns up at the site of the damaged artery and acts as a band aid. This, by the way is a good thing. It is the Cholesterol’s job to repair the damage. The only reason the LDL turned up in the first place was because of the inflammation of the artery that was caused by high Glucose levels in the body.

“Blaming LDL Cholesterol for Blocking an Artery and Thus Causing a Heart Attack is Like Blaming Firemen for Causing a House Fire, Just Because They Are Always At The Scene!”

Therefore, when you fast, you give your body a chance to burn off the glucose which in turn reduces inflammation all over the body including your arteries. This then means that LDL Cholesterol does not need to try repair the damage which in turn ends up blocking your arteries. Another powerful reason for partaking in intermittent fasting!

Decreased Cancer Risk

It is becoming more commonly known that cancer cells feed and thrive on sugar. When you fast or consume a low carbohydrate and sugar diet, you literally create an environment in your body in which cancer cells can nor thrive nor survive.

benefits of intermittent fasting source

The cancer statistics for the UK alone (as shown above) is worrying. This devastating illness impacts millions of people a year globally. There are many lifestyle factors that can be a catalyst for cancer. Some of them being;

  • Over consumption of alcohol
  • Smoking
  • Absorption/ingestion of carcinogens 
  • Many more….
cancer lifestyle stats 1


“More Than 40% of Cancer Cases Can Be Prevented!”

NBC News

Some causes of cancer are sadly either genetic, or as a result of old age. It is a fact that as we age we become more at risk of many forms of cancer. However, as we can see from the NBC News statistics, almost have of the cancer cases we see today could be prevented through smart lifestyle choices. We can also see from the above chart that smoking, obesity and alcohol are the leading causes of self inflicted cancer.

As already mentioned, cancer cells feed on glucose. In fact cancer cells are 10x more receptive to glucose and insulin which in turn means that they are 10x more likely to thrive and multiply in a glucose infested body. On the flip side, cancer cell do not feed of fat and oxygen (fat oxidisation) for fuel at all. Therefore, if one intermittent fasts intensely and regularly, their glucose and insulin levels will drop and as a result significantly reduce the chances of cancer cells thriving in the body.

Less Risk of Alzheimer’s, Dementia and Parkinson’s Disease

benefits of intermittent fasting

There are a few theories as to how fasting can help prevent, or relieve the symptoms of Alzheimer’s and other related neurodegenerative  diseases. Nothing is 100% proven yet, however promising signs are beginning to emerge in recent research.

A study carried out by the Department of Food and Nutrition at Hoseo University in South Korea found that intermittent fasting may help prevent age related memory loss and mental deterioration.

are there any benefits to intermittent fasting


The concepts discussed in the study its self are fairly complex and make for very heavy reading. In essence though, the research looked at the effects of fasting on a group of rats with a form of Alzheimer’s disease in comparison to a group of rats without the disease. interestingly, positive results were observed.

“Intermittent fasting may be an effective intervention to protect against age-related metabolic disturbances, although it is still controversial.”

– Department of Food & Nutrition, Obesity/Diabetes Center, Hoseo University

A popular theory as to how fasting helps prevent and reduce symptoms of neurodegenerative diseases is to do with how the brain utilises glucose for energy.

It is known that degenerative diseases in the brain are mainly caused due to a high amount of dying brain cells. One theory is that with Alzheimer’s and related conditions, what has happened is that the brain is no longer able to use glucose for energy. For some reason the mechanism that the brain uses to use glucose has malfunctioned. Yet for most people it is glucose that their brains primarily run on. However, If you fast for a period of time, the body begins to produce ketones out of oxidised fat, which then can be used as an alternative fuel source by the brain. In many ways, the brain actually prefers ketones as a fuel source as it is a cleaner and more efficient form of energy. The one switches to using ketones for fuel rather than glucose, then a lot more of the brain cells are able to survive resulting in a reduced risk and/or relieved symptoms of many neurodegenerative  diseases.

Improved Immune System and Decreased Risk of Illness

Intermittent fasting can also drastically increase the efficiency of your immune system which may help reduce the frequency and severity of some illnesses you encounter.

In short, fasting kills off white blood cell responsible for fighting illness and disease. Now this may sound like a bad thing, but actually what happens is that this encourages the T cells to produce even more white blood cells which gives a healthy boost to your immune system. . I am going to let fasting and keto expert Thomas DeLauer explain in this in more detail.

Boost in Testosterone and Human Growth Hormone (HGH)

It is now known that insulin inhibits the production of testosterone and human growth hormone when it is released. Not only this, but healthy natural fats are essential for hormonal balance and testosterone production in both men and women. For this reason, when one undergoes prolonged fasting and the body is functioning primarily on fats, testosterone levels are significantly increased. In fact, every time we eat, for 3-5 hours afterwards out testosterone levels are significantly reduced.

are there any benefits to intermittent fasting


The European Journal of Endocrinology released a study that proved the effectiveness of fasting in boosting testosterone and HGH levels. The research found that fasting increased the levels of Luteinizing Hormone in the brain which signals to the sex organs to produce more testosterone. The study also found that Lutenizing Hormone increased by 20% in obese individuals and a massive 67% in non-obese individuals when fasting. This is a significant increase which can have many positive effects on your life.

The most common benefits of elevated testosterone levels are;

  • Increased muscle mass
  • Decreased body fat
  • Increased libido
  • More energy
  • Strengthened bones

And Many more…

Improved Mental Focus and Enhanced Mood and Less Stress

When you fast for a a significant amount of time, your body starts to burn its own fat for fuel. The body oxidises this fat and produces something called ketones. These ketones are an alternative energy source for the body once all the glucose has been used. Ketones are actually a preferred energy source for the brain. They cross the blood/brain barrier more easily and they also provide more energy per unit of oxygen than glucose. The result of result is using ketones for fuel during periods of fasting appears to lead to reduced depression and an enhanced positive mental state in those who partake in prolonged fasting. Many subjects even report a euphoric feeling after 2-3 days of fasting.

A review by Fond Et Al looked looked into how many studies they could find that examined the effect of fasting on mood and brain disorders. They conducted a search on the Medline, Web of Science and PsycINFO databases to see what they could find.

are there any benefits to intermittent fasting


The clinicians found a total of 92 studies!

“Clinicians have found that fasting was frequently accompanied by an increased level of vigilance and a mood improvement, a subjective feeling of well-being, and sometimes of euphoria.”

Fond G Et Al

As a collective, these studies found that;

  • After 10 days of fasting, patients with clinical depression reported an 86% remission rate of their condition.
  • Other studies found that fasting or calorie restriction in healthy participants or those with medical issues showed improved energy levels, improved mood and reduced depressive and anxiety symptoms.
  • Another study that looked at the effects of fasting on Muslims during the month of Ramadan found that they experienced a decrease in both manic and depressive symptoms.

It would appear that fasting has enormous benefits on mood and mental health. Just another one of the many positive by products of fasting.

Autophagy and Anti-Ageing Benefits

are there any benefits fasting

Essentially, autophagy is the bodies process of eating its own deformed and dead cells, and replaicing them with new ones. This is the cornerstone of the anti-ageing process. However, autophagy and the anti-ageing benefits associated with it, are only achievable through a more extreme and prolonged form of fasting. Generally a fast of more than 19 hours needs to take place before autophagy begins to occur in the body.

So how is autphagy stimulated in the body as a result of fasting? Well, when the body runs out of glucose (as it does when we are in a moderate to severely fasted state), the body starts burning its own body fat for fuel. As a direct result of this, the enzyme AMP – Activated protein kinase is released. This enzyme is only released as a result of burning fat for fuel rather than glucose. When this happens the process of autophay begins and the healthy cells in the body break down the dead or malforrmed ones whch then allows new cells to be created.

The most common benefits of autophagy are;

  • Increased longevity
  • Reduced cancer risk
  • Prevention or delay of neuro-degenerative diseases
  • Reduced inflammation
  • General anti-ageing

And many more…

In Summary

In summary, intermittent fasting is something that can be extremely beneficial for your health, fitness and fat loss goals. The positive effects of fasting go far beyond aesthetics and fat loss. They go as far as helping to improve your general health. With ever more people around the world becoming interested in fasting, maybe the current global obesity and health epidemic will be a thing of the past in the not too distant future.

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