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The Benefits of Fasting

Theres a lot of talk lately about Fasting but what is it?

The practice of not eating or drinking, fasting is one of the most natural things we can do.

Providing amazing benefits such as weight loss, energy conservation, and a clearer mind, we’ll unlock the secret of this gift.


Never forget your dog is a wolf!


I love this saying, it holds true to so many situations, this one included. You see, just as your dog is a wolf, the same holds true for humans, we are apes and ultimately animals. This is necessary to remember especially when our day to day life is so unrecognizable to the one our bodies adapted to.


In the same way, our bodies haven’t adapted to low fiber processed foods, it is equally true we have not adapted to the abundance of food available to us today. We adapted to our hunter-gatherer environment, meaning our bodies are accustomed to going extended periods of time between feasting on a fresh catch. It was only with the advent of agriculture 12,000 years ago that we could even begin to think about eating one meal a day let alone three meals a day.

“The Europeans took their [Native Americans] lack of defined eating times as evidence that they were uncivilized and had them change. In short: The 3 meals a day paradigm is not based off of our biological needs.” – Three Squares by Abigail Carroll


Types of fasting


When deciding whether or not to incorporate fasting into your diet, it’s important to establish the different variations. Listening to your body and lifestyle, you’ll be able to find an option that best suits you.


The 16/8 Approach


In this method, you have an eight-hour window where you eat, followed by a sixteen-hour window of fasting. A good example of this would be someone eating between the hours of 12-8pm or 10-6pm.


This approach works best for those wanting to fast on a daily basis and typically involves missing breakfast. It’s important to keep your eating window consistent while prioritizing nutritious food.


If the longer style fasts below look too daunting, then this fast is a perfect solution that’s easy to follow. The eating window can also be extended or shortened to provide more or less of a challenge.


Suitable for:

  • Newcomers just starting out
  • Experienced Paleo goers
  • Those looking to lose weight


The 24 Hour Fast


This fast has you abstaining from food for a period of 24 hours and is recommended for experienced fasters. When first starting out, this method should be used once to twice a week to see benefits. Once you become comfortable, you can begin doing it every other day to further increase its effectiveness.


To begin, choose a meal you wish to end on. For example, if you pick breakfast at 7 am, you wouldn’t eat anything until 7 am the following morning. The same would be true for lunch and dinner, resulting in a 24 hour fast.


On non-fasting days, eat like you normally do and make sure you don’t under eat. Some think they can maximize weight loss by undereating, however, the opposite is true. When you restrict the amount food you consume, your body takes this as a very bad sign. You enter survival mode and your body tries its best to hold onto your fat stores.


Suitable for:

  • Experienced fasters looking to expand the practice.
  • Those comfortable with the 16/8 approach


Extended Fasts


The last method covered here today and one rising in popularity, has you fasting for several days. This type isn’t for the faint of heart and requires you to fast for a minimum of three days.


Extended fasts have many success stories related to them; the most famous being of a 456-pound Scotsman who fasted for 382 days. After his fast, he had lost 276 pounds and hadn’t experienced any ill effects from it (1).


An important consideration to note with these longer fasts are the potential drawbacks. Many believe muscle loss is greater on extended fasts, with a man fasting for 44 days losing mostly muscle (2).


Nutrient deficiencies can also be a major issue, considering they aren’t being consumed. As a result, it’s vital to take supplements if you’re considering a very long fast.


Suitable For:

  • Those with extreme obesity or insulin resistance
  • People who can follow this under the care of a physician


Health Benefits of Fasting




The greatest benefit that fasting holds and one we try to find in all but this one place is longevity. This pursuit of a long and healthy life has captured our imagination and ambitions in culture for millennia. We all know of the fountain of youth, but is the same true for fasting?


While fasting undoubtedly isn’t as intriguing as a fountain that brings eternal youth, it is a method that science has accepted since the 1900’s to consistently increase longevity in animals; leading up to a 30% increase in lifespan. More surprising is the universality of the results, affecting Yeast cells all the way up to monkeys (3).

“Calorie restriction (CR) extends lifespan and retards age-related chronic diseases in a variety of species, including rats, mice, fish, flies, worms, and yeast.” – Leonie K Heilbronn

Weight loss


Losing weight while fasting can be incredibly effective and unlike the calories in, calories out myth; doesn’t come at a cost of losing muscle mass either. This is because when we fast we transition into ketosis which is the mode our body goes into to burn our fat stores.


More time


An added benefit of fasting is the reduction of time spent eating food. When we save these hours by not eating, we actually gain them back; allowing us to accomplish a great deal more than before!




Following a diet is hard, it’s one of the reasons why I love Paleo so much! Paleo sticks to simple fundamentals and doesn’t make you waste time tracking the macronutrients you consume. However, I hit a snag when I noticed the benefits of ketosis and wanted to try out the keto diet.


Ketogenic diets, have you restrict your carb intake to less than 20 grams a day, which can be intrusive. Instead, fasting alongside Paleo will provide many of the same benefits of keto, while being simple to follow.


Gives your stomach a much-needed break


If we were to follow the guidance to eat every 3-4 hours; we would wake up and have breakfast, followed by lunch and finally dinner, with countless snacks in between. Looking at this, the only time not spent eating or digesting a meal is when we’re sleeping!


As I’ve said before and I will continue to say again, we didn’t evolve with constant access to food. When we don’t give our digestive system time to rest; our enzymes lose their efficiency, slowing our metabolism and increasing weight gain amongst other things.


Mental Clarity


The mental clarity experienced when fasting isn’t just a placebo effect. Fasting places us into ketosis, allowing us to burn our body fat for energy. This process converts fat into ketones which are then used to fuel our body. Ketones are the preferred fuel source and pass directly through the blood-brain barrier; estimated to perform 25-30% more efficiently than carbohydrates.


Researchers have also found that fasting promotes the growth of new brain cells, possibly aiding learning, memory, and recovery (4). Furthermore, production of the brain’s BDNF protein is increased, protecting against Alzheimer’s and Parkinson’s disease (5).


Human Growth Hormone Levels increase


Growth hormone, commonly used as a performance-enhancing drug is actually produced naturally by the body. Fasting has been shown to raise levels of this hormone by up to 2000%, providing a whole host of benefits (6):


  • Cell Growth, reproduction & regeneration
  • Calcium retention
  • Anti-aging properties
  • Prevents memory loss


Common Fasting Questions


What liquids am I allowed to consume?


It is easy to unknowingly break a fast due to consuming a drink that spikes your glucose levels and eliciting an insulin response that kicks you out of ketosis and as a result breaks your fast. It’s recommended to avoid all forms of processed drinks and stick with these unsweetened choices:


  • Water
  • Black Coffee (no milk or sugar)
  • Tea


Can I exercise while fasting?


There is no inherent issue with exercising while fasting and can actually cause you to feel more energetic, with a more stable access to energy. This is because when fasting, your body transitions from glucose/carb dependence to burning your more stable fat supply.


You may see a decrease in performance during high-intensity workouts, where glucagon is primarily used for energy. Staying as active as possible is your best bet during a fast and will keep your mind off of food. If you don’t want to do high-intensity exercise, walking, riding and swimming are all great ways to keep active.


Will I Lose Muscle when Fasting?


This depends, if you’ve become fat adapted by following a ketogenic diet, you won’t see much muscle loss. This is because your body now knows how to meet your energy demands through stored fat and ketones. The much lower glucose requirement your body now has can be met without breaking down muscle.


The same is not true for sugar-burners and you will most likely see some muscle loss. This can be alleviated by eating a protein-rich meal before fasting; converting the protein into your much-needed glucose before targeting your muscles.


How often should I fast on Paleo?


How often you fast depends on several factors; if you’re looking to lose weight, extended fasts can be great but require preparation and supplementation. In general, if you follow the 16/8 method or a variation, daily fasts can be sustained and tolerated. When considering longer fasts that range into 24 hours, once a week is plenty. Two times a week can also be fine, however, any more and you’ll have a tough time maintaining enough energy.


Should I Fast when Trying to Gain Weight?


As someone who’s had a tough time putting weight on in the past, fasting can get in the way. The occasional 16/8 fast won’t destroy your progress but probably isn’t necessary, especially on Paleo. Sticking to the fundamentals and weight training regularly, you should start seeing gains.


Should I take vitamins or supplements during a fast?


My general philosophy with supplements is that you should be gaining them from foods. However, in extended fasts, that possibility isn’t there and supplements should be taken to account for the lack of nutrients.


That said, you should take into account that the effectiveness of these vitamins and supplements is hindered without food.


Should Pregnant Women Fast?


Although fasting produces many desirable effects and benefits for most people, the same isn’t necessarily true during pregnancy. Several studies have found changes to the fetus with the most worrying being an increase of gestational diabetes (7, 8, 9).


How should I track my progress?


With any change to your diet, you’ll want to monitor it to make sure you’re responding well to it. Simply using a notebook to write down these factors can be a great help:


  • Objective measurements: weight, body fat percentage, waistline, hours slept, weight lifted, reps completed, distance ran/walked/cycled.
  • Subjective measurements: mood, energy levels throughout the day, energy levels during workouts, performance during cognitive tasks.


With the subjective measurements, it may be helpful to use a simple 1-10 scale. This can alleviate some of the issues when it comes to measuring subjective experiences.




Fasting is an easy way to enter into ketosis without having to strictly monitor our carb intake while at the same time providing exceptional health benefits. The biggest benefit I see when fasting is an increased mental capacity, often leaving me impressed with how much I achieved that day.


Before you go, I do want to express that while fasting is a wonderful tool, we must with all things, use it in moderation. Abusing this tool and fasting every day can lower your base metabolic rate; reducing the efficiency of results. I personally recommend fasting for no more than 5 days a week, with the other days reserved for time-restricted eating.

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