I am a regular listener and a fan of Damien Blenkensopp’s The Quantified Body podcast. He podcasted excellent coverage and reportage of his five day water fast so I decided to try it and report back to compare and contrast my experience.
Before the fast I was intimidated by the idea of doing it. Despite hearing evidence from Damien’s experience, I had the idea that I would be in a stupor for five days. I also envisioned that I would have hardcore hunger pain.
I had an embedded fasting advantage and simultaneous disadvantage in the fact that during my military days I attended and graduated from the Army Ranger School. Small ration amounts and long patrols allowed me to experience true near starvation and the associated pain that goes with it. I remembered those pains and dreaded experiencing them again. I was pleased to find the fast was in no way as stressful as Ranger School.
During the fast I took about 3 liters of water a day and had no other liquid or food of any type. Not a single cheat. The closest I came to opening the glove compartment in the car and seeing a box of Tic-Tacs. I resisted though I had lust in my heart.
Why I did it
Other than being inspired by The Quantified Body podcast, I have been trying to test my food and supplement intake to drop my blood glucose levels. I thought a fast would be a way to see my glucose and ketones in a food free state. And I liked the challenge of it.
What I measured
For the fast I measured:
- Heart Rate Variability each morning after waking up
- Blood Glucose twice a day
- Blood Ketones twice a day
- Weight each morning
- How hungry I felt nine times a day (spread evenly)
- How awake I felt nine times I day (spread evenly)
- Cognitive function using the Quantified-Mind app each afternoon
- Muse Calm Score each morning
- Sistolic and Diastolic Blood Pressure each morning
What I Found
Overall, I found that fasting for five days is not stressful, does not put me into a stupor and my glucose level dropped to a range Damien and his co-fasters reported seeing. As a technique, a water fast yields ketosis like I had never experienced before. I lost 10 lbs. And I had horrible bad breath for four of the days. Here are the details.
Heart Rate Variability
My heart rate variability (HRV) averaged an rMSSD of 44 during the fast and my average over multiple months prior was 50. The lowered period on the graph just prior to the fast was due to travel.
Glucose & Ketones
Fasting glucose clearly dropped from an average of 101 down to 69 for days 3, 4 and 5. Of interest is that it took my body two days to adjust.
It took me the two days to bring my ketones up to a point where they were more plentiful than my dropping glucose. I had three days of the glucose-ketone ratio being under 1.0, which reportedly has a therapeutic effect. This was a great outcome. Here are my afternoon (postprandial) readings:
Obviously weight was going to drop as I was not eating. I was an average of 192 pre-fast and lost 10 lbs by the end of the fast.
Here is a before and after picture that shows for me what losing 10 lbs looks like. Picture on left was the night before the fast, right the last day of the fast.
Nine times a day I measured how alert I felt because my story was that I would be in a stupor. A measure of 3 is normal, 2 would be actually yawning. You can see I was yawning tired in the first few days then my body compensated. I was never exhausted.
I felt hunger pangs throughout but intermittently. Only once did I have a headache related to the fast which was the end of day 2. Notably day 3 on my awareness of hunger diminished and you can see the jump in scores (higher is less hungry).
My Muse calm score seemed to drop off through the fast. I felt calm and good each morning on waking you can see the drop when the fast started. Bears further investigation.
Notes On The Experience
My original idea was to have a five day period to focus on the fast and be sequestered away to save energy, but life intruded. I had several social commitments that had been scheduled well before I decided to do the fast to include a Meetup and a charity event.
One significant drawback is my breath was awful. According to Damien and his fellow fasters, this is due to increased acetone that comes out through the breath. When you are discussing deep thoughts at a charity event while spewing breath that can knock a buzzard off a manure wagon you have discovered the downside of fasting.
Anecdotally I felt great when I was focused on a task and was able to get a lot of work done. But when I was interrupted or had a something suddenly come up I experienced fairly hot and palpable irritation. This seemingly lowered ability to handle context switches deserves further study.
This is the most meaningful and impactful experiment I have done. I ended the fast having experienced the fact that our bodies have a deep reserve of nutrients and that eating huge meals three times a day is completely unnecessary. Doing this has raised my interest in finding my own optimal nutrient level. Thanks for Damien for the inspiration. Good times ahead.