Fasting Part 2: My personal experiment with an extended 3-day fast

Hello again! I’m going to assume that if you are reading this post, you have read the first part of this article on fasting and its benefits. If not, you can find it here in PART 1. I’ll use some of the terminology I outlined in part 1 freely, assuming you already know its meaning.

So as I was researching the benefits of fasting for the first part of this post, I became increasingly curious and eager to experience the effects on the body after fasting for 24+ hours. We are talking: increased insulin sensitivity, autophagy, increased growth hormone, healing and system resetting. Sign me up!

Of course I couldn’t just jump right in –  there is the major type 1 diabetic (T1D) caveat to keep in mind: how the heck do you manage insulin dosing with zero consumption of food? I had discovered through my reading that acidosis can occur with extended fasts, and I didn’t want to couple that with elevated levels of ketones and high blood sugar (read my post on ketoacidosis here). Some of the research I found on fasting for T1Ds around Ramadan describe some candidates finishing a 24 hour fast with a hypo (low), and some with a hyper (high). This could, in part, be the result from too little or no insulin administered.

So how was I going to do this? I decided to take this challenge on myself, unsupervised. Now please hear me – I do not recommend doing this for just anyone! I have a pretty in-depth, fairly nuanced understanding of my body’s insulin requirement and need. I have been experimenting with keto, exercise, and intermittent fasting for several years now, and I felt confident that I could manage this myself. I do not recommend someone who is just thinking of trying fasting to stop eating for 3 days and stop taking insulin. I don’t want to be responsible for you heading to the ER!

So I decided that I wanted to try a 3 day, 72 hour fast (it ended up being 71 thanks to daylight savings, but never mind!). I decided that I wanted the first day to be a work day, as I’d have lots to keep me busy and occupied, and keep my mind off hunger. Plus I’m very accustomed to intermittent fasting at work and eating just at lunch time. I therefore decided to eat my last meal on a Thursday evening, and begin the fast overnight and into Friday. This means that I would not consume anything but water, tea and black coffee for 3 days, planning to break my fast on Sunday evening.  I also got my hands on some electrolytes so that my minerals would stay in balance.My “last supper” as it were, was a fantastically delicious strip lion steak with Alfredo sauce drizzle over it and the veggies. If I wasn’t going to eat for 3 days, I would make my last meal a good one!

My mouth-watering "last supper" of steak, cauli, broccoli and asperagus, topped with Alfedo sauce.
The liquid electrolytes I picked up. 10-20 drops per glass.

Ok, so here we go! Friday morning came, and it’s so funny the effect the brain has on signalling our bodies. I was hungry and had stomach grumbles at 9 am! I’m completely accustomed to not eating until noon, so this was totally my mind playing tricks on me because it knew it wasn’t getting fed!

I started Friday morning off with perfect blood glucose (BG) – 5.9, or around 108. I decided to decrease my long-acting basal insulin by a quarter, so from 16 units down to 12. I thought this was a safe bet to keep the background insulin needs met and keeping insulin present to reduce blood PH acidification. 

Well, one glance at the following graph and you can see what happened. My BG was in range, but steadily falling until around 6pm. I saw the writing on the wall and there was nothing to be done but take some correctional glucose tablets. DOH! Did this mean that my fast was broken? I did a bit of research and the opinions were mixed. Some stated that any digestive activation that elevates blood sugar breaks a fast. HOWEVER, this I believe was referring to a non-diabetic person as it would subsequently result in an insulin response. In me, this action wouldn’t cause an insulin response because I wouldn’t be giving myself any insulin!  An insulin response was also cited as the mechanism for breaking a fast. So I decided to run on the basis that correctional glucose wouldn’t have many adverse effects against the fast so I decided to carry on and I’m very glad I did! (I had considered at first throwing in the towel when I thought I’d already broken the fast and what was the point if none of the benefits were to be enjoyed?)

This shows Thursday night's dinner absorb and fall within range by Friday morning. Notice the steady fall throughout the day.

This would be a good place to explain that when keto/fat adapted, we are not reliant on glucose as the primary energy for the brain, so it makes low BG events less stressful and life-threatening, which is a good thing when you look at the following graph! This is something Dr. Keth Runyan pointed out in his book about ketosis for type 1 diabetics that I read early on in my keto education). I had serious low blood sugars during the overnight period of that Friday. One before bed, which I treated with 4 glucose tablets, two in the middle of the night, and the second one lasted for several hours (which I slept through!), and then I woke up low as well. Each one treated with 4 glucose tablets. HOLY CRAP! Ok, so obviously 12 units was way too much insulin. 

Above you can see where I treated the falling blood sugar at 6pm, and the ensuing hypos for the rest of the over-night.

So on the Saturday, after correcting with MORE glucose tablets, it came up nicely to 5.8 and stayed there for several hours. I decided to try delaying my basal insulin to see what effect on my BG no insulin on board would have and it stayed pretty steady until around 12:00, when I saw it start to rise. So I took 8 units this time with the aim to avoid the overnight hypos like the previous night. 

Above you can see how, around 12, my blood sugar starts to steady rise.

Let me veer away from diabetic stuff for a moment and talk about how I felt on this second day of being fasted. It was AMAZING! I can’t believe the energy I had and how my body just wasn’t the slightest bit hungry. Now call me crazy, but I had ear marked this weekend for a small demo/reno project at my place, so rather than postpone it I thought, “hey, it’ll keep me distracted”! So I demoed and framed a new doorway, did all the clean up and then cleaned the whole house, bringing me to around 8:30 pm. It was insane, I could just keep going, and going, and going. I’d finish one job and then start another one! I had read about this and was thrilled that I was able to experience it for myself. It made me believe that I had indeed not interrupted the benefits of the extended fast by ingesting corrective glucose. 

The door way I framed! And the amazing drywall face and hair.

So Saturday night came and went, and I had another night plagued with low blood sugar. Another epic low actually, take a look below! I was basically low from 1am until I woke up. So 8 units is still too much. Or is that coupled with doing a reno project all day? It’s hard to say. Thank goodness for being adapted to running on ketones. So I held off on bolusing my long-acting again as I didn’t want any overlap, and I actually continued to fall throughout the day until I corrected mid afternoon and then stayed steady until I broke my fast around 6pm. I took 4 units of long-acting when I broke my fast. 

This day looks wacky! Low blood sugar from basically 1am onward, came low again around 2, then stayed steady until I ate dinner and that spike speaks for itself!

I actually had my first bite of food around 5, wanting to ease into warming up my digestion (which I had read about). I had some of my favourite probiotic coconut vanilla yogurt  which is low carb, high fat, and SOOOOO delicious! Man was it good! 

The first spoonfull getting prepared.
First-bite bliss!

I then had some Cambozola blue cheese, about half the block!

The cheese I shouldn't have had!
Baked sablefish and veggie stirfry

Then for dinner, an hour or so later, I had some baked sablefish and veggie stir fry and….I. OVER. DID. IT! I felt so full and sick. If I could do a redo, I would have had none of the cheese and wait for the fish and veggies. I’d also stop the moment I felt the first signalling of being full. I’m usually pretty good about stopping when I feel full now, but I think I went 2 or 3 bites over, and there was still so much left on the plate so I felt a bit pressured to eat more. BIG MISTAKE!

I was uncomfortable for the rest of the evening. Oh well, live and learn! The whole experience was certainly a giant learning opportunity. It’s all how you look at things. I didn’t “make mistakes”, I just tried a few things and they didn’t work out perfectly. 

What was the big takeaway?

So I’ve been asked several times whether or not I’ll do another extended fast. Absolutely! The way I felt on Saturday and Sunday was totally worth it just on its own. I definitely want to avoid those hypos though. So I will certainly alter my insulin program when on my next extended fast. I’m thinking starting with bolusing 6 units of long acting on day one and seeing how that trends with my BG. That would be a safe starting point as it’s half the amount I started with this time and less than the lowest I took this first try. In theory it should more or less half the amount that my BG drops. That then leaves room to go down to 4, or even 2 units as needed. I don’t think I’ll go without insulin whatsoever because I saw this time what happens to the BG trending graph when the long-acting finishes up. So for me, the happy number will be somewhere between 2 and 6 units of long-acting insulin bolused once a day. 

I have also noticed since that my insulin sensitivity is higher. This is one of the main goals! Remember, insulin sensitivity is a marker of a healthy metabolism, so if I’m able to absorb and utilize my food with lower amounts of insulin, only good can come from that.

Please do remember though that everything I’ve discussed pertains to me and my body.  I do not recommend that a T1D jump into an extended fast blindly without fully understanding what happens physiologically, and how your body responds to insulin. I also don’t recommend copying my insulin doses. Look, even I over-shot and I have a pretty good understanding of how my body works. I also did a quick risk analysis, and decided that in the case of an extended fast, it was better to air on the side of lower rather than higher, to avoid risk of acidosis. Also remember that if you aren’t fat-adapted, or adapted to running on ketones, your body will react much more seriously to hypos so this was less of a risk for me. I have been fat adapted on and off for 4 years, solidly for 18 months. 

So would I recommend an extended fast for a type 1 diabetic?

Yes, there is nothing we can’t do that a “normal” person can do. We just have to be educated, well prepared and adaptable. As I said before, I would recommend speaking to your diabetic specialist, and if you are unable to see them before you want to fast, make sure you have done a ton of research and really understand what will be happening in your body from both a fasting and insulin perspective. 

Live well and live strong! 

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