Intermittent Fasting

By February 3, 2021 No Comments

“Breakfast is the most important meal of the day”

I’m sure you have heard this maxim many times over the years.  This adage about breakfast has become so commonplace that it is widely accepted as fact.

But did you know that it first appeared in a 1917 issue of Good Health magazine, edited by Dr John Harvey Kellogg. Does that name sound familiar?

Of course it does.

The same name is attached to Corn Flakes, a product co-created by Kellogg.  Kellogg’s used the slogan to promote their new product which was marketed as a healthy, ready to eat, morning meal.

The food you choose to break your fast may be an important thing to consider; however eating a highly processed, calorie-dense food first thing in the morning is not as important as Dr Kellogg would like you to believe.

In this blog post we will break down some common misconceptions about diet and eating in general and take a look at the practice of intermittent fasting.

So let’s get started.


In contrast to modern society, ancient hunter-gatherers didn’t have supermarkets, refrigerators, or fresh food available year-round. Sometimes they couldn’t find anything to eat for extended periods.  As a result, humans evolved to be able to function without food for extended periods.

Fasting from time to time is likely a more natural way of eating than eating 3–4 (or more) meals per day.

The deliberate practice of fasting also exists throughout human evolution and for thousands of years across many different religions and cultures worldwide, including Islam, Christianity, Judaism, and Buddhism.

So what is Intermittent Fasting?

Intermittent fasting as a dietary trend or health protocol has gained popularity over the past decade, exploding in popularity to become one of the most popular health trends globally.

The practice is endorsed by celebrities from Joe Rogan, Terry Crews, and Hugh Jackman (yes, Wolverine does it) to Halle Berry, J. Lo, and Kourtney Kardashian.

Intermittent fasting is not a conventional diet, but more accurately described as an eating pattern.  It is an umbrella term for various eating patterns that cycle between periods of eating and fasting.

You may also have heard it called intermittent calorie restriction, intermittent eating or time-restricted feeding.

While other diets often have strict rules and regulations, intermittent fasting does not specify which foods to eat or avoid, but rather when you should eat them. Because of this, it is generally considered less restrictive, more flexible, and easily adaptable to fit just about any lifestyle.

Many people use intermittent fasting to lose weight, improve their health, and simplify their lifestyles.

A growing body of evidence shows intermittent fasting can have powerful effects on your body and brain. It may reduce the risks of many chronic diseases, including diabetes, cancer and heart disease. There are also claims it can lead to an extended lifespan.

Intermittent Fasting Methods

Several methods of intermittent fasting exist. Each of these can be effective, but figuring out which one works best depends on the individual.  Each method involves splitting the day or week into periods of eating and fasting.

During the fasting periods, you eat either very little or nothing at all.

I will discuss the three most popular methods here:

The 16:8 method, AKA Leangains protocol:

This method typically involves restricting your daily eating period to 8 hours, such as 12–8 p.m., then fasting for the other 16 hours. Although 16:8 is the typical ratio, this method is also commonly done with ratios of 15:9, 14:10, 17:7, and 18:6.

The eating period in this method generally allows for 2 to 3 meals. It can be achieved simply by not eating after dinner in the evening and either skipping or having breakfast later.  Water, black coffee/tea, and other non-caloric drinks can be consumed during fasting periods.

16:8 intermittent fasting is easy to follow and can provide real results with minimal effort.  Many people instinctively eat this way by skipping breakfast every morning. If you are one of those people, this method will not be too hard to adopt; it may only require you to delay your first meal for the day by an hour or two.

If you are the type of person that is hungry as soon as you wake, and you generally have a big breakfast, this may be harder for you to get used to at first. Begin with a shorter fasting period of 12 or 13 hours and extend it gradually every few days or every week until you reach the desired fasting time.



This protocol was created and popularised by health blogger and self-proclaimed intermittent fasting expert Brad Pilon. It involves fasting for 24 hours once or twice a week, such as not eating from dinner until dinner the next day.

As with the 16:8 protocol, water, black coffee and tea, and other non-caloric drinks can be consumed during fasting periods.

Fasting for 24 hour periods may be difficult to achieve for many people, especially in the beginning, making this protocol a more advanced fasting method. Again, if you find it hard to achieve, start with a shorter fasting window and increase it gradually as you become used to it. Your body will begin to adapt, and your hunger cravings will reduce with consistent practice.


The 5:2 diet:

This diet, popularised by British author and journalist Dr Michael Mosley, requires you to consume only 500–600 calories on two non-consecutive days of the week.  During the rest of the week, you eat as you usually would.  For example, you might eat as normal every day except for Mondays and Wednesdays. On those days, you may only eat two small meals or snacks of 250-300 calories each.

As with the other methods, you can consume water, black coffee and tea, and other non-caloric drinks during fasting periods.

This method can be easier to achieve than the Eat-Stop-Eat protocol because you don’t completely abstain from food for the fasting period.  As critics correctly point out, there are no studies conducted into the 5:2 diet itself. Still, there are plenty of studies on the benefits of intermittent fasting as a whole.

Of the above methods, the 16:8 protocol is the most popular and probably the simplest, most sustainable, and easiest to maintain.

What are the Benefits of Intermittent Fasting?

Weight loss: 

Intermittent fasting can help you lose weight and reduce fat without consciously restricting calories. All of the above methods can assist in weight loss by limiting the time available for eating.  A side effect of having less time to eat often means eating fewer meals and reducing the number of calories consumed in that period.

The critical thing to remember is to eat nutritious foods and not overeat during the eating periods.  Weight gain is still possible following these protocols, especially if the foods consumed are calorie-dense and have a low nutritional value. If you are fasting for 18 hours a day but pigging out on Doritos and Donuts for the other 6, you are still likely to gain weight.

Weight loss is one of the most common reasons people begin intermittent fasting, and it can be a potent weight-loss tool.


Fat loss:

Teaching your body to utilise fat stores as energy is one mechanism by which intermittent fasting aids fat burning and weight loss.  By helping you eat fewer, and burn more, calories, intermittent fasting affects both sides of the calorie equation.

Without getting too carried away and turning this into a scientific paper, here is a quick breakdown on how your body turns food into energy.  When you eat a meal, especially one containing carbohydrates, your body digests and processes this food in the stomach.  Enzymes in the stomach break it down and convert it to a type of sugar called glucose.

Glucose is the most accessible energy source for the body’s needs and its preferred energy source. Glucose is released into the blood and used for energy.  Insulin, a hormone released by the pancreas, is responsible for regulating glucose in the blood.  When glucose levels rise, insulin is released into the blood signalling cells in the body to take in the glucose for energy.  When cells have sufficient energy, insulin signals the liver to take up the remaining glucose and store it as glycogen for later use.

So how does this affect fat burning?

Your body will use any glucose in the blood as its first source of energy. Once depleted, glycogen stores are accessed and converted to glucose for further use by the body.

During the “fasted state” glucose and glycogen stores are depleted, and your body looks to other energy sources to use. The next best energy source is fat.  Body fat has a large amount of stored energy.

When energy needs exceed the amount provided by dietary sources, the body must liquidate some of its fat tissue for energy.  These fat stores are converted to fatty acids and ketones to power the body and the brain.  This process is also one of the main reasons many people succeed with a ketogenic diet (keto).

Working out in a fasted state may also enhance fat burning.

When working out in a fasted state, your body has depleted glucose and glycogen stores. Your body adapts and sources energy from the fat stored in your cells.  The more you fast, and the more efficient your body becomes at using fat for fuel, the more likely it is to use it as an energy source.  This is especially true for cardio type training.


Weight loss and fat reduction are not the only benefits of intermittent fasting.

Another benefit is that it can simplify your healthy lifestyle.  Intermittent fasting is a popular diet because it’s easy to follow, flexible and sustainable in the long term.  Eating healthy is simple, but can sometimes be incredibly hard to maintain.

One obstacle to maintaining a healthy lifestyle is the work required in planning and cooking healthy meals.  Intermittent fasting can help simplify your healthy lifestyle.  Reducing the number of meals in your day means you won’t need to plan, cook or clean up after as many meals as before.

The benefits of fasting also go far beyond weight loss and simplifying your lifestyle. Many of the benefits linked to intermittent fasting are backed by science.  Studies show it can have profound effects on the cells and hormones of your body. When fasting, several things happen in the body both on a cellular and molecular level.

Along with adjusting hormone levels making stored body fat more accessible,  Your cells also initiate essential repair processes and change the expression of specific genes.

Here are some changes that occur in your body when you fast:

Hormonal changes:

  • HGH: Human Growth Hormone levels skyrocket, increasing as much as 5-fold, benefiting both fat loss and muscle gain.
  • Norepinephrine (noradrenaline): Levels of this hormone also increase which can play a role in fat loss
  • Insulin: Fasting improves insulin sensitivity and reduces insulin resistance. Blood insulin levels drop dramatically in the fasted state. Lower insulin levels make stored body fat more accessible for energy and protect against Type 2 diabetes development.
  • Metabolism: The above hormonal changes may increase your metabolic rate by 3.6–14%.

Other changes in the body:

  • Improved Cardiovascular health: Intermittent fasting may help reduce many of the risk factors for heart disease, including LDL “bad” cholesterol, blood triglycerides, inflammatory markers, blood sugar and insulin resistance.
  • Reduced Inflammation: Some studies demonstrate reductions in inflammatory markers which are a key driver in many chronic diseases.
  • Cellular repair: Cells initiate essential repair processes. One of these processes, called autophagy, involves cells digesting and removing damaged and dysfunctional cellular components, including misfolded proteins, toxins and waste products. This process, linked to several positive health effects, allows for the generation of newer, healthier cells.
  • Reduced Cancer Risk: Some animal studies suggest that intermittent fasting may prevent cancer.
  • Improved Brain health: Intermittent fasting increases the brain hormone Brain-derived neurotrophic factor (BDNF) and may aid new nerve cell growth. It may also protect against conditions such as Alzheimer’s disease and Parkinson’s disease.
  • Gene expression: Numerous studies have shown that fasting affects gene expression.

Fasting is grounded in serious research, and more studies are coming out all the time, showing its numerous benefits. Keep in mind that a lot of that research is still in its early stages. Many of the studies on intermittent fasting have been small and short-term or conducted on animals. There is a lot to learn about the effects of fasting on the human body. Many questions are yet to be answered in higher quality human studies.  However, the results coming out of current literature are promising.

Keep in mind that one of the main reasons for its success is that intermittent fasting helps you eat fewer calories overall.  Binging and eating massive amounts during eating periods may lead to no weight loss and negate all the other health benefits.


Drawbacks of Intermittent Fasting

Intermittent fasting may be associated with many health benefits. Still, it does come with some drawbacks and may not be right for everyone.  Restricting your intake to just eight hours per day can cause some people to eat more than usual during eating periods in an attempt to make up for hours spent fasting.  This may lead to weight gain, digestive problems and the development of unhealthy eating habits.  Conversely, some people may struggle to meet their calorie needs during their eating windows.  This is particularly relevant for endurance athletes, high-level sportspeople or bodybuilders or those with extremely physically demanding jobs.

Intermittent fasting can also cause some short-term adverse side effects in the beginning, such as hunger, weakness and fatigue. These side effects will often subside once your body adapts to the practice.


Who Should Be Careful Or Avoid It?

While Intermittent fasting can be suitable for most people and is generally considered safe for healthy adults, it is certainly not for everyone.  If you’re underweight or have a history of eating disorders, you should not fast without consulting a health professional first. Intermittent fasting is also not recommended for women trying to conceive or those who are pregnant or breastfeeding.  In these cases, it may be harmful.  It is also probably not a good idea for children to be fasting.

Those with underlying medical conditions should consult a doctor before trying intermittent fasting.  If you’re taking any medications, have diabetes or low blood pressure, this is particularly important.

There is some evidence that intermittent fasting may not be as beneficial for women as men.  Some people recommend that women only fast 14–15 hours because they seem to do better with slightly shorter fasts. Further anecdotal reports exist of women having menstruation issues when beginning intermittent fasting, which stopped once they started eating normally.  For these reasons, women should be careful with intermittent fasting. No specific studies are looking at these issue in humans. However, studies in rats have found intermittent fasting can make female rats emaciated, masculinised, infertile and cause missed cycles.  It is essential to ease into the practice and stop immediately if there are any problems like amenorrhea (absence of menstruation).


Safety and Side Effects

Hunger is the main side effect of intermittent fasting.  In the early stages, you may feel a bit weak, and your brain may not perform quite as well.  These side effects are often only temporary.  It can take some time for your body to adapt to the new meal schedule and get used to using stored energy such as glycogen and fat.  That being said, intermittent fasting has an outstanding safety profile. There is nothing dangerous about not eating for a while if you’re healthy and well-nourished overall.

If you have any concerns or experience any adverse side effects while fasting, be sure to consult your doctor.


Frequently Asked Questions

Here are answers to some of the more common questions about intermittent fasting.

What should I eat during my eating window?

Eating healthy and nutritious food during your eating windows is essential if you want to get good results from intermittent fasting.  Many people believe that if they fast for 16 hours, they can eat whatever they like in the other 8 hours of the day, this is not the case.  It is still possible to consume more calories than your body requires even when not eating for 16 hours a day.  Excess calories will lead to weight gain.  You will also not be getting all the micronutrients, vitamins and minerals your body requires to perform optimally.

Can I Drink Liquids During the Fast?

Yes. Water, tea, coffee and other non-caloric beverages are fine. There are differing views on what constitutes breaking a fast; however, the general consensus is that anything below 50 calories will keep you in a fasted state. In particular, coffee may be beneficial during a fast, as it helps blunt feelings of hunger.  Do not add sugar to your coffee, but small amounts of milk may be okay.

Isn’t It Unhealthy to Skip breakfast?

Short answer. No!

Along with promoting dietary guidelines that have contributed to an obesity epidemic in most western countries, the processed food industry has indoctrinated people to believe this maxim as gospel.  One problem is that many stereotypical breakfast skippers have other unhealthy lifestyle habits. If you ensure you eat healthy food for the rest of the day, then the practice is perfectly healthy.

Can I Take Supplements While Fasting?

As mentioned above, there are differing views on what constitutes breaking a fast; however, most supplements are okay.  Just remember that some supplements may have a caloric content.  It is preferable not to take these supplements during fasting; however, if you do, make sure they do not exceed 50 calories.  It is also important to note that some supplements, such as fat-soluble vitamins, may work better when taken with meals.

Can I Work out While Fasted?

Yes, fasted workouts are fine, and in some instances may increase the fat burning effects of fasting. Suppose you usually train in the morning and typically have something to eat beforehand. In that case, you might find that you lack strength or stamina at first.  Your body will adapt, but this may take some time.

Always make sure you are drinking plenty of water.

Training fasted is more likely to impact strength training, rather than cardio type training negatively.  Always listen to your body;  If you feel dizzy or light-headed stop or reduce the intensity.  As your body adapts, exercising in a fasted state will become easier.  Track your progress and find out what works for you.  Also, make sure you are drinking plenty of water.

If you notice a significant performance decrease, make sure you are eating enough calories during eating periods.  Some people also recommend taking Branched Chain Amino Acids (BCAAs) before, or during, fasted workouts.

Will Fasting Cause Muscle Loss?

All weight loss methods can potentially cause muscle loss, especially if there is a significant calorie deficit.   Maintaining adequate protein intake (1.6-2.2g protein per kilo of body weight) and incorporating some resistance training is important for maintaining or increasing lean muscle mass during fasting. Some studies show that intermittent fasting causes less muscle loss than regular calorie restriction.

Will Fasting Slow Down My Metabolism?

No. On the contrary, there is some evidence that short-term fasts actually boost metabolism. However, longer fasts of 3 or more days can suppress your metabolism.


Should you try it?

Intermittent fasting is not the panacea of dietary approaches. It is not necessarily something everyone must do to be healthy.  It’s simply one of many lifestyle strategies you can use to improve your health. Eating real food, exercising and getting adequate sleep are still the most important pillars of good health and wellbeing.

There is no one-size-fits-all solution when it comes to nutrition. The best diet for you is the one you can stick to in the long run.  Intermittent fasting is great for some people, but not for others. The only way to find out which group you belong to is to try it out.

If you feel good when fasting and find it to be sustainable, it can be a powerful tool to lose weight and improve your health.


Getting Started

If you think Intermittent Fasting will be a good fit for your lifestyle and want to give it a try the first thing to do is pick the times for your eating and fasting periods.  The 16:8 protocol is considered by many to be the simplest and most sustainable way of intermittent fasting; This can be an excellent place to start.

An eating window that works for many people is 12 p.m. to 8 p.m.  This window will mean that you stop eating after your last meal of the evening, fast through the night while sleeping, and skip breakfast.

It does not matter what times you choose for your eating window; what matters is that it will work for you and your lifestyle.  If you work until 7:30 p.m. every night and eat dinner after getting home from work then 12-8 probably won’t work for you.  Experiment a little bit and find a time frame that works.

Without even realising it there is a big chance that you’ve already done many intermittent fasts in your life.  If you’ve ever eaten dinner, gone to bed, slept in late, and not eaten until lunch the next day, then you’ve probably already fasted for 16+ hours.  Some people instinctively eat this way. They just don’t feel hungry in the morning.

Using a smaller fasting window of 15, 14 or 13 hours, to begin with, may help ease you into the process until you get used to it.  It will take some time for your body to adapt, and by not overdoing it from the start you will set yourself up for continued success.

If you find it easy and feel good during the fast, you could increase the fasting period or try moving on to more advanced fasts.  The advanced fasts are not absolutely necessary though; you will still see great benefit following the 16:8 method alone.

Another approach is to fast whenever it’s convenient by skipping meals from time to time when you’re not hungry or don’t have time to cook.  There is no need to follow a structured intermittent fasting plan to derive some of its benefits.  Experiment with the different approaches and find something that you enjoy and fits your schedule.

Remember to include plenty of nutritious, healthy foods during your eating window.  Including good sources of protein and various healthy whole foods in each meal will ensure you get the most out of this dietary practice. Remember that binging on junk food will most likely counteract the positive effects associated with Intermittent fasting and may do more harm than good to your health.

Some Simple Tips to Help you Start

Don’t overcomplicate things!

Experiment with things and do what works for you.  The human body is complex, and no two people are the same.  Dietary approaches, no matter what they are, may work well for one person, but not so well for another.

If everyone is going out for breakfast after the gym on Saturday morning and you don’t want to be that only weirdo sitting at the end of the table sipping your black coffee. Don’t. One day of not hitting your 16 hour fast will not undo all the work you have put in over the previous weeks and months.

If you feel like having a latte one morning, do it.

If you want to eat breakfast with your kids on the weekend, that’s okay too. If you’re too strict on yourself and deny some of life’s little pleasures, you may find it too difficult and will be unlikely to continue it long-term.

Keep busy

If you are sitting around always thinking how hungry you are, it will make the process a lot harder.  Organise your fasting periods for maximum efficiency and minimal discomfort.  Begin your fast after your last meal of the evening before going to bed.  By the time you wake in the morning, you will have likely already fasted for close to ten hours. Find something productive to fill in the rest of your time so you’re not just counting down the minutes until you can eat again.

Track Your progress

Everybody will react to intermittent fasting differently. It’s up to you to listen to your body and see how making these adjustments change your body and affect your training.  Keeping track of how you respond, any physique changes, and your workout results will help you make more informed decisions on whether the practice works for you.

And Finally – Don’t expect miracles

Intermittent fasting can positively affect body composition, brain health and hormone regulation, but it is not a magic pill. Don’t think you can just fast for 16 hours a day and look like Arnold Schwarzenneger in a month when you don’t train and eat rubbish for the other 8 hours of your day.  Be sensible.


AN IMPORTANT CAVEAT: I am not a medical practitioner or a dietitian.  The information in this blog should be viewed as educational only.


Eliot Hird

Author Eliot Hird

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