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72 Hour Water Fast as a Brain Injury Survivor

Doing an extended 72 hour water fast is something I've been looking into and researching for over 2 years. The reason it took me so long to finalise my decision is that I couldn't see how I could manage to succeed given my already low levels of energy post encephalitis and brain injury and I wasn't entirely sure it would bring me any benefits.


How my fasting journey began

After seeing a nutritionist with sound experience of chronic fatigue and brain injury in August 2021, I made lots of tweaks in terms of nutrition and I also added a few supplements that she recommended. I quickly noticed many benefits such has, massive reduction of my gut issues, my skin rashes cleared up, I started dropping some weight (I had put on 7kgs), I started noticing a rise in my energy levels, my cognition improved and I overall felt much better.


After adapting to those changes for a few months, I started introducing 16:8 fasting into the mix. I would essentially fast following my last evening meal (typically 6pm in our household) and break my fast anywhere between 10-11am the next day. I initially thought I'd be starving, but I was surprised by how easy the transition to intermittent fasting was. The other surprise was how quickly I saw my levels of energy rise further and how I started noticing further improvements in terms of how my weird wonderful brain was operating.


Seeing the benefits that my nutrition tweaks and the intermittent fasting had had on my overall health, I became even more interested in exploring this piece of the puzzle further. This is essentially how I began reading even more extensively about all things relating to nutrition including water fasting.


What is a 72 hour water fast?

In this blog I want to relate a bit more on my personal experience with water fasting, but below is a bit of the theory behind some of the benefits that have been linked to extended fasting.


Diagram of the 72 hour water fast stages

What are the stages of a water fast?


There are various types of fasting so if a 3 day water fast isn't exactly the thing for you, the attached diagram will allow you to get acquainted with some of what is going on in your body over the time restricted eating period that you may feel comfortable trying.


Essentially, your body preferred source of energy is glycogen (a form of glucose) and as long as it is readily available, that is what your body will use for energy production.


Your body will then switch to using your fat cells as a source of fuel which is a state often referred to as ketosis.


After 24 hours of fasting, your body will start repairing itself by getting rid of old and damaged cells. This process is called autophagy.


Your hormones will then go through a shift and start working towards reducing inflammation. The level of ketones will continue rising, body inflammation will continue to decrease and further autophagy will occur.


By the time you reach 72 hours, your body will start producing stem cells and creating new immune cells.



What are the health benefits of fasting?

Some of the health benefits linked to fasting that have been backed by science include:

  • Reducing insulin resistance

  • Reducing inflammation

  • Boosting brain function and cognition and may prevent neurodegenerative disorders

  • Aiding weight loss

  • Increasing growth hormones (involved in metabolism, weight loss and muscle growth)

  • Improving blood pressure, triglycerides and cholesterol level (enhancing heart health)

  • May be beneficial for cancer patient (boost the immune system and exposes cancer cells)

  • Increasing longevity by building resistance to age related diseases


My personal experience of a 72 hours water fast

I'll share my personal experience of the 72 hours water fast by breaking it up in blocks of times during which I noticed some changes.


12-36 hours of fasting

Since my body and brain are already used to the 16:8 intermittent fasting, the first 36 hours were relatively easy for me. I say 36 hours because I essentially began fasting after my last evening meal, got to 24 hours and then headed off to bed for the night which took me to the half way mark of 36 hours.


I did feel a little wave of hunger around what would have been my first meal and dinner time, but I rode those off fairly easily topping up on my water intake and then sharing a cup of tea with the family at dinner time.


36-60 hours of fasting

The 36-48 hour part of the fast was quite interesting for me. I was expecting to be really hungry and for the second day to be my hardest day, but for the most part, it went really well. Don't get me wrong, had I not set off on this fasting experience, I would definitely have ingested food, but I found that hunger mainly came around my usual meal times. Understanding why that was was honestly a bit of a key for me in completing this fast.


During my research on extended fast, I got acquainted with the hunger hormone that gets released in our body called ghrelin. The release of that hormone naturally occurs around our meal times and signals us that it's time to eat. This hormone peaks around our meal times and then plummets. That's why we can at times feel really hungry, but if for one reason or another we miss out on a meal, our hunger tends to die down until our next meal. So with an understanding of that mechanism, I knew that if I could push through this short phase of hunger, I'd eventually feel okay again. Our bodies obviously all react and work differently, but this turned up to be very much the case for me.


Another interesting thing that occurred for me during that 36-48 fast period is that I felt as though my brain was on steroid. When outside the hunger periods, it felt like my brain operated at a really fast pace. It felt sharp, clear but at times also a bit too much in overdrive. I tend not to like that feeling too much as it mimics how I can experience a panic attack. Therefore, when I found my brain leaning too much in that overdrive end of the spectrum, I'd take a time out and do a few breathing exercises. I took the time to remind myself of what was happening inside my body by doing the fast, the changes that were taking place in this particular phase of the 72 hours fast and my reasons for attempting this extended fast. This approach worked well to keep me focused, present and to slow down that overdrive feeling that I wasn't enjoying so much.


That second evening, we watched a few episode on Netflix. To be honest, I'm not sure my brain could have handled much else. Then off to sleep I went until the next morning which brought me to 60 hours into the fast.


60-72 hours of fasting

Prior to starting the fast, I thought that the last 12 hours of the 72 hours water fast wouldn't be so bad as in my head it was me working my way to the finish line. Surely my will-power would prevail and that it wouldn't be so bad. However, I personally found that last 12 hours to be the hardest. Not so much from an hunger point of view though. I physically started feeling pretty tired, my brain had lost that euphoric feeling that I had experienced the previous day and at times, I could go through dizzy spells. So I took things slow and didn't put too much pressure on myself. I kept myself distracted, but I knew I wasn't going to break any records on that day. I tuned into whatever signs my body and mind were sending me to make sure I could complete the extended fast.


For the sake of full transparency, I worked on prepping dinner for the family on that last day and it was pure torture. There was no reasoning with my ghrelin hormone release anymore. My husband Greg kept me on track and accountable as I was just so close to the finish line and to help take my mind off things, he finished cooking dinner for me...yeah, he's a gem!


Guess what, ghrelin eventually died down, I lost track of time and noticed I had officially completed my fast 45 minutes after my official time. I was pretty proud of myself. I had initially thought about heading to bed to extend it until the following morning, but the last 12 hours had been quite trialling in various ways so my will power to do so had gone out the window and I felt it was ok to respect and acknowledge that as well.


So off I went to start re-introducing food by prepping my first bone broth.


The day following my water fast

I woke up feeling ok and with a reasonable amount of energy. After waking up, I prepared another bone broth, went for a short morning walk with the dogs and then carried on as per a usual work day. Apart from the morning bone broth, I then aimed to get back to my typical intermittent fasting 16:8 pattern.


Again, I want to be transparent here about my personal experience. Although I was quite conscious about my choices of first food to reintroduce, my tummy was funny for most of the day. I therefore made sure to keep well hydrated. I'm unsure about what I could have done different to avoid that. From my research, this is something that can happen after an extended water fast and perhaps it's one of my natural body response. The fatigue, dizzy spells and brain fog from the 60-72 hours had however lifted and I operated as per usual on that day. The tummy rumbles settled the following day.


Would I do a 72 hour water fast again?

Absolutely, I didn't have all the tools to monitor and measure the real impact on my body, but it's probably something I'll look into when I prepare for another one. Since I wasn't doing the fast for weight loss, I didn't take measurements either but in hindsight, I wish I had just to better understand what might have taken place. I did drop 2.5kgs (about 5.5pounds) but within 5 days I had put half of it back.


In addition to lowering inflammation, which from testing I know I'm genetically geared unfavorably for, the idea of a body detox and re-boot has been one of my main motivation for doing it...particularly after noticing some of the benefits that I had experienced with intermittent fasting.


I did have periods where I was very hungry, but I surprisingly handled them pretty well. Understanding the extended fast stages was beneficial in helping me manage my hunger efficiently.


After completing the 72 hours water fast, I noticed that I was extra conscious about my food choices making sure I was making the best possible decisions not to wreck all my good work. I'm hoping that it might help me sustain healthy habits when it comes to nutrition.


Tips to complete a water fast

These are tips from my personal experience, I'd encourage you to also do your own research and perhaps consult your physician if you have any concerns.

  • Be in the right mind frame. After 2 years of tossing the idea around I was finally ready. Take the time you need to determine the pros and cons.

  • Read, read and read some more about the process. Understanding what's happening has been beneficial to keeping me on track.

  • Make sure you drink lots and lots of water.

  • Listen to your body as is it no doubt an added stress for it. Slow down if you need to & remember that you can adapt your usual activities during the fast.

  • Plan ahead so someone can help around meal times, it does help with willpower.

  • Start small. Perhaps try a type of intermittent fasting first and see how your brain and body respond. This may give you the additional motivation to try an extended fast.


If you are thinking about doing one, get in touch if you'd like to find out more from my personal experience. If you have already completed one, please share your best tips as I'll definitely be looking at doing this again.


If you'd like to read more on fasting in the context of brain injury recovery:




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