My Experiences with Extended Fasting

In this blog I intend to share my experiences with prolonged (over 24 hour) fasts. If you are new to fasting, or simply want to know WHY I would consider going for extended periods without food be sure to read my article Fasting: How Skipping Meals Can Burn Fat & Increase Lifespan.

Also, make sure you sign up to my email newsletter, as I will be updating this blog each time I do a new fast (eventually I would like to do a 7 day or longer fast…)

My Experiences with Extended Fasting

Fast #1 -  3 day fast – 26th July 2016

I have been using IF for over 5 years now, it was a key protocol in my bodybuilding success whereby I did daily 16 hour fasts. As you can see below, fasting definitely helped me drop the excess body fat! But my point here is that I had plenty of experiencing with regular intermittent fasting of around 12-16 hours.

Fasting for Fat Loss - find out how here 

However, it was only in early 2016 that I did my first 24 hours fast. To be honest, the first time I did this it felt like an eternity. I went lunch to lunch, and it was hard. I truly believe a lot of the difficulty is behavioral however.

I was in a ketogenic state going into the fast, having been low carb for a few months prior, so from a physiological point of view my body should have been well equipped to go a day without food.

Anyway, I didn’t die and I started introducing 24 hour fasts into my diet on a weekly basis. Soon I was doing 30 hours without any issues.

This led me to my next challenge… a 3 day 72 hour fast.

It has been shown that after 2 days of fasting immune function is boosted,  so I figured that would be a great target for my first prolonged fast.


72 Hours Without Food

My last – prefast - meal was a big Sunday night roast at 7pm on July 24th 2016. The next day I felt fine, but I did feel a tad flat – I think it was more the fact knowing that I would be depriving myself of life’s simple pleasures for 72 hours!

The First 24 Hours

My energy levels were still solid. I was drinking a lot of tea and water, and making sure I got as much morning sun, day time sun and grounding as possible. I also worked in a lot of Cold Thermogenesis sessions including mid winter ocean swims.

The Middle 24 Hours

In the afternoon of day two I decided to do some outdoor sprint intervals. I usually train in a fasted state so I didn’t notice any negative impact on my performance. Afterwards I felt fine.

The Final 24 Hours

At the 48 hour mark I made dinner for my girlfriend who was working late. Barramundi, steamed vegetables and sweet potato fries. I sat with her at the table while she ate. I didn’t feel ‘hungry’ at this time, instead I felt slightly depressed – right in front of me was a tasty nutritious meal, eating it would give me a good hit of dopamine inducing pleasure, and I was missing out on this!

Day 3 morning I woke up feeling rather flat. Not my usual self. Saying that my sleep wasn’t the best that night (tracked using my Oura Ring (read my review HERE). Also I noticed I had diarrhea that morning. This hadn’t been an issue the previous days.

During the day I regained energy and felt good.  I should mention that up to this point I had never felt ‘hungry’. I have done 3 bodybuilding competitions with semi-starvation low calorie diets. During those pre comp days I had times when I literally couldn’t sleep because I was so hungry. It was horrible. You cannot stop thinking about food, you would salivate at the thought of a meal. This didn’t happen during the first 60 hours of this fast.

Hitting The Wall 

However, around 1pm on day 3 (66 hours in) I got really hungry, mouthwatering, stomach growling hungry. I drunk a lot of water and this passed. Later that afternoon I simple hit a wall. It was about 4pm and I was trying to write a blog article. I simply couldn’t type concise sentences. I gave up and decided to read my book. I noticed I couldn’t process the information – rereading the same paragraph over and over.

I remained in this state of haze for an hour. I had considered doing a 4-5 day fast, but at this point I decided the lost productivity wasn’t worth the extra fasting time. I was an hour way from my 72 hour goal, so I thought I would try something. I had a bottle of Brain Octane MCT oil in the cupboard. Knowing that I was going to eat in an hour’s time I had a tablespoon of this fast acting fat. Within 10minutes I noticed renewed energy and mental clarity.

I was tempted to push on for another 24 hours but decided it was probably best to stick with a 3 day fast and try a longer fast another time. The MCT oil was definitely interesting – even though it wouldn’t meet the requirements of a water fast, I do feel it would help with future extended fasts – especially when some productivity was required!


Reintroducing food:

My first ‘post fast’ meal was a chicken broth soup. I actually burnt my mouth while eating the food up, so the meal wasn’t that enjoyable! I popped a few digestive enzymes to help my gut process this food but felt fine during the meal and afterwards.


The Next Day (Post Fast)

The next morning – after a 12 hour fast – I had fish head broth with seaweed, sardines, sauerkraut and a small amount of dark chocolate. I had more diarrhea before this meal. But felt fine afterwards.

Body Changes

Unfortunately I didn’t track my ketone levels, body fat, appearance or anything other metric. I will look at doing this next time.


What’s next?

I really want to do a 5 day fast, and in fact after the MCT surge I really think I could push it out longer. There comes a point though where you have to way up the pro’s and cons. What are the benefits of doing an extremely long fast? And is it worth missing out on the simple pleasure that is eating food?!


Fast #2 - Week Long Fast

It has been a while since I wrote this article (and did the 3 day fast). I continue doing fortnightly 24 hour fasts, but I haven't got around to doing anything longer. And to be completely honest I don't have any intention to do an extended fast in the near future!

But, one of the Hormone Reset Members has recently done a 7 day fast. He journaled his experience and sent it to me. I asked if I could republish it in this article for readers, and he said yes.

You can read it below:

My 7 Day Fasting Experience

My goal going into my extended fast was 7 days, but not fully knowing what to expect I was willing to accept 5 days as a successful extended fast.

Three days before my fast I began preparation by limiting meat products and trying to eat more fruit.  I also ingested 1 tablespoon of bentonite clay that I soaked overnight in a glass of spring water.

I thought that I would continue use throughout fast but opted against it because of some cramping I had in the three days prior.

Throughout the fast I tried to rest as much as possible. I did work weekdays. I walked more than normal and performed Founders exercises every other day [Alex - this is the mobility training I have Hormone Reset members do].

That was the extent of my exercise for the week. I also went to bed earlier than normal. Mainly to avoid the urge to eat.

Tuesday March 6th 2018

I ate a small dinner around 4:30 pm. (Oura Ring Deep Sleep Tuesday night 1 hr. 25 min.)


  • Basal Body Temp - 97.8 [Alex - all my clients track their body temperature, you can see why HERE]
  • Wed. Deep Sleep - 1 hr. 0 min.

Feeling very motivated and felt no hunger at all.  Walked a good bit that evening. That afternoon I tested for ketones with KetoStix and it showed a “trace” amount of Ketones in urine. Went to bed early.

Cup of coffee with 1 Tbsp ghee for breakfast.  Spring water with and without salt when I felt thirsty. Multi-vitamin in morning


  • Basal Body Temp - 98.0
  • Deep Sleep – 46 min.

No hunger at any time during the day. Energy levels good. Felt no ill side effects. Ketones increasing 1.5-4 mmol/L.

Cup of coffee with 1 Tbsp ghee for breakfast.  Spring water with and without salt when I felt thirsty. Multi-vitamin in morning


  • Basal Body Temp (BBT) 97.8
  • Deep Sleep – 38 min.

Probably worst day for feeling down.  Headache, almost as if caffeine withdrawal, most of the afternoon and evening. Felt slightly hungry around dinner. Used a salt water enema that evening. Read that could help with detox symptoms such as headache. Ketones high one shade from max on scale-  8 mmol/L.

Cup of coffee with 1 Tbsp ghee for breakfast.  Spring water with and without salt when I felt thirsty. Multi-vitamin in morning


  • Basal Body Temp (BBT) 98.5
  • Sat. Deep Sleep - 41 min.

Woke up early to drive to Harrisburg 3 hours away to watch Wrestling Championships. Felt much better all day.  No headache and highly motivated. Thoughts were clear.

However, after driving 6 hours and excitement of matches I was tired when I got back home. Stayed up later (10:30) to spend time with family, slept in on Sunday. Ketones high - 8 mmol/L 

Cup of coffee with 1 Tbsp ghee for breakfast.  Spring water with and without salt when I felt thirsty. Multi-vitamin in morning


  • Basal Body Temp - 98.6
  •  Sun. Deep Sleep - 31 min.

Morning was good, I did some work around the house. The afternoon was the hungriest I had been.  I think it was because we had family over for dinner. I helped and probably should have stayed out of kitchen. I had several glasses salt water that helped curb hunger.  Ketones high - 8 mmol/L 

Cup of coffee (no Ghee) for breakfast. Spring water with and without salt as needed. No Vitamin


  • Basal Body Temp - 98.6
  • Deep Sleep - 28 min.

Back to work.  Felt great. Best I had felt since Ketones really started to climb. No hunger at all throughout the day. Ketones high - 8 mmol/L

Cup of coffee (no Ghee) for breakfast. Spring water with and without salt as needed. No Vitamin

Tuesday (Eating Day)

  • Basal Body Temp (BBT) 98.5
  • Deep Sleep - 1 hr. 10 min.

Finish line in sight.  Dreamed of food all day.  What I wanted to eat over the next few days filled my thoughts. Planned my breaking the fast meal. Went to work but got no work done at all.   

Cup of coffee (no Ghee) for breakfast. Spring water with and without salt as needed. No Vitamin

  •   4:30 pm    I ate 5 small 1 inch square pieces of watermelon.
  •   5:30 pm    one apple and cup of bone broth.
  •   6:30 pm    few more pieces of watermelon, an apple and cup of bone broth
  •   7:30 pm    becoming ravenous. Could have eaten everything in the fridge. Ate two apples, on with almond butter, piece of cheese and cup of bone broth.
  • 8:30 pm    two more apples both with almond butter, bone broth, cheese and one scoop of ice cream.
  • 9:35 pm    I went to bed to try to save myself.

Wednesday (1 day after)

  • Basal Body Temp (BBT) 98.0
  • Deep Sleep - 1 hr. 12min.

Breakfast:   I ate a small breakfast of scrambled egg with avocado and bone broth. Resumed all supplements per Ongoing Health diet.

Lunch:  Romaine lettuce salad with homemade ceasar dressing and two sardines.

Dinner:  Two apples with almond butter. Lemon Chicken and steamed veggies

Thursday (2 days after)

Resumed three meals of normal size

Friday (3 days after)

I noticed one significant change that I had not read about.  Both sides of my face between my ears and jaw became very sore.

What I realized was my salivary (parotid) glands were very sore to the touch.  Not sure why. Overworked???

Not only sore to the touch but as soon as I would put a piece of food in my mouth and take a bite I could feel them working. It was weird. 

Equally weird were certain foods i.e. cheese, smoothies, and butter (yes I tested butter too) produced no sense of salivary glands working while foods such as meat, veggies, chocolate produced instant soreness and feeling of glands trying to secret saliva. 

This lasted until Sunday with Saturday being the worst. Even tried a hot compress to ease soreness on Saturday. Monday felt no sensation at all.



Be sure to sign up to my newsletter to be the first to hear about my future experiences with extended fasting. I plan on doing a 5 day and a 7 day fast. I may even look at doing a longer fast one day, but we will see! Do you have experience with extended fasting? If so, please share them below, I'd love to hear all about them.

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This blog post was written by Alex Fergus. Alex is an ISSN Sports Nutrition Specialist, Fitness Professional and certified Superhuman Coach who continues to expand his knowledge base and help people across the world with their health and wellness. Alex is recognized as the National Record Holder in Powerlifting and Indoor Rowing and has earned the title of the Australian National Natural Bodybuilding Champion. Having worked as a health coach and personal trainer for over a decade, Alex now researches all things health and wellness and shares his findings on this blog. Learn more about Alex's Credentials HERE.


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