2020 Year-end 3-Day FASTING Journal
Preface
As crazy as the year of 2020 is, it is still a year of abundant learning, experience and reflection for me.
It constantly reminded me of the fragility of human lives, the importance of unity and above all, how lucky I am and have been through this wide ride. While there are lots of things to reflect mentally in this holiday season, I have also decided to cleanse my body – which has gone through a tremendous amount of stress in the year of the RAT – by doing a multi-day fast.
Thus, this note is my personal journal on this experience, which will include things as follows.
- Body weight,
- A couple of bio markers I can measure at home, namely, blood pressure and blood glucose,
- The state of my sleep, tracked by Oura Ring,
- And most importantly, my feelings through the experience such as physical energy, mental energy and focus, and other changes worth mentioning.
A Word of Caution
Please note that I daily intermittent fast (usually in the format of 20/4) and implement a monthly two-day fast. I have also lived a relatively strict ketogenic lifestyle for the past 4+ years. All this means that I am relatively more used to fasting and my body is, hopefully, more metabolically flexible in terms of burning my fat to provide energy.
So please do your research and consult your doctors before starting a fast.
Plan of Action
- As the name implies, during the fast, I will only limit my food intake to water, black coffee and green tea. I will also add sea salt to replenish my minerals that’s peed out during the fast.
- I will also try to remain active by modest walking or hiking to Victoria Peak as well as squats and push-ups at home (gyms are closed due to Covid-19).
- In the morning, I will keep doing my daily meditation and Wim Hof breathing, after which I will do a cold shower of at least 60 seconds.
- As for entertainment, I will try to read as much as possible, in addition to record my fasting experience.
Data Summary & What I Have Learnt
While below you can find my detailed journal and sharing of the 3-day fast journey (which I highly recommend reading), I have summaries some of the key data I’ve collected and the key takeaways from this experience in this section.
Lesson / Thoughts #1: Low BG Levels & High Energy
It is widely accepted that hypoglycemia is defined as a blood sugar level below 3.9mmol/L. However, I felt fine both mentally and physically when mine was constantly below 3.9mmol/L for more than 36 hours.
Not only was I able to read and learn fast, walk long-distance and do body-weight exercise, my mental clarity and focus was much better than normal. I also had this heightened motivation to learn and write during the fast.
Why would this happen?
While I did not test my blood ketone numbers, it is logical to assume that my body was fueled by the breaking down of fat and resultant ketone bodies. This helps explain why I did not feel any lack of energy during the fast; my brain and body was fueled by an alternative source of energy, which many researches regard as cleaner and more efficient for the brain and certain organs.
From the perspective of human evolution, homo sapiens (us) constantly went through cycles of fast (when there is no food available) and feast (for example, after a successful hunt), before they learnt how to store foods (even then, they were NOT constantly eating). To make sure that we did not go distinct during hard times, our body evolved to utilizing our stored energy (glucose through glycogen in liver and muscles, and fat). Even more importantly, evolution made sure that we became smarter during tough times, as it would be a stupid strategy to make us dumber, weaker or slower if the goal of the universe (or mother nature or 道) is to pass along our genetic information.
It has been well proven that fasting and exercise boost brain growth and plasticity by boosting brain-derived neurotrophic factor (BDNF), an important molecule for improved learning and memory formation. I was definitely benefiting from this process as my ketones were upregulating my BDNF expression.
Lesson / Thoughts #2: Sleep, Caffeine & Stress Hormones
One of the things I struggled with during the journey was my bad sleep, especially on Day 2.
- Apart from meaningfully less Deep Sleep, it is also interesting to note that my REM sleep actually substantially grew on Day 3 and Day 4 (after breaking the fast, 124mins). This seems to be contrary to some of the studies indicating shorter REM sleep during fast.
What I wanted was good sleep, together with a fast, which could have a synergistic effect on my body. In hindsight, the two cups of coffee on Day 1 probably was to blame, as it added to the already higher level of stress hormones during the fast. A higher level of cortisol and adrenaline apparently is not conducive to a good night of sleep.
Therefore, lesson learnt for the next multi-day fast:
Do not consume excess caffeine during the fast (including Day 1).
Detailed Journey
Day 0
I got together with a few friends for Christmas and we had Sichuan foods to celebrate it. It was not the healthiest food for my keto diet – given the high veg oil content (see my note on Linoleic Acid) – but I was in a mood to indulge a bit with festivity in the air. I stopped eating at about 3pm and this marked the start of my fasting.
Day 1
- Body weight: 63.7KG
- BP: 115/69
- BG: 4.7mmol/L – bit higher than my normal fasting level. I guess there was some sugar in the foods I had yesterday.
- Sleep: total sleep of 7 hours and 28 mins with 83% efficiency, REM sleep of 90 mins and Deep Sleep of 65 mins – within normal ranges for me.
Comments / Thoughts
I felt good on the 1st day with plenty of energy, which is expected given my daily intermittent fasting practice. I actually had more than 90 seconds of cold shower, which felt great.
I ended up going back to the office, reading some broker emails and research reports on 2021 outlooks as I felt pretty clear-minded and motivated to learn. I did some nice walking around Central and Admiralty in between and logged in 4X15 body weight pushups and a few sets of squats.
Hunger started to set in at around 3pm as the body roughly remembers when it was fed yesterday. This is also quite normal given the internal circadian rhythm – I felt this during my monthly two-day fast as well. So I did not really pay attention and continued reading.
I measured my BG level again at about 6pm and it was at 4.4mmol/L – bit higher than my expectation. Either my sugar level is supported by a reversal of my glycogen stores in my liver (from foods I had yesterday) or muscles or I have been efficiently using my blood ketos to generate energies. It is most likely a combination of both.
Day 2
- Body weight: 63.1KG
- BP: 122/77
- BG: 3.7mmol/L at 5am and 3.1mmol/L at 4:30pm
- Sleep: total sleep of 4 hours and 24 mins with 80% efficiency, REM sleep of 44 mins and Deep Sleep of 20 mins
Comments / Thoughts
Tricks by Stress Hormones
Likely due to my two cups of coffee on Day 1 and higher stress hormones (such as cortisol and adrenaline) caused on fasting, my sleep quality was sharply impacted with only 20 mins of deep sleep. The body needs to maintain a certain blood sugar levels (cannot go to zero) by a process of gluconeogenesis and those stress hormones are released to achieve that goal.
- The higher stress hormones are also likely behind the slightly elevated BP levels.
- What’s interesting to note is that my respiratory rate went down meaningfully to 15.5/min, compared to my average of 17.0/min. I need to dig into this but guess this is somewhat indicative of lower need for oxygen during fast.
Hunger
When I woke up at about 4:45am, I felt this strong hunger that lasted for about 1 hour. It felt like the body was telling me that I needed to stop fasting and refeed. It went away after I started reading.
Mental Clarity and Focus
Despite the short and low-quality sleep, I felt fine and mentally clear and focused after waking up. I got up immediately and started reading Ray Dalio’s Principles for about three hours before heading outside for a walk.
I was able to read fast, understand clearly and later recall most of the key points. The mental clarity continued throughout the day and I was able to finish the book by 1pm at a café; so I read about 300+ pages in half a day, which is more than my usual pace.
Exercise
I went out for a long walk when the sun was shining to Kennedy Town and it was a beautiful day outside with bit of breeze. My energy was not bad, despite feeling a bit weak when climbing stairs. But still, I was able to walk for more than 90 mins without much effort.
Day 3
- Body weight: 62.4KG
- BP: 113/58
- BG: 2.9mmol/L at 8am, 2.8mmol/L before breaking fast and 3.8mmol/L two hours after meal
- Sleep: total sleep of 8 hours and 28 mins with 86% efficiency, REM sleep of 119 mins and Deep Sleep of 30 mins
Comments / Thoughts
Normal Blood Glucose Level?
Starting from Day 2, my blood glucose level dropped to what conventionally is regarded as hypoglycemia (below 3.9 mmol/L) and later it even dipped to below 3.0 mmol/L, a level is regarded as critical.
I did not really have any symptoms of a typical hypoglycemia and I continued to have very sharp mental clarity and strength.
However, it did put a mental burden when I saw the number went to below 3.0 mmol/L at the night of Day 2 as I live alone. So I had 10 grams of collagen, hoping it would lift up the sugar level.
Sleep
Immediately after having the collagen, I felt my body temperature warming up (proven by Oura Ring). I apparently slept better compared to Day 2 with much longer REM sleep (lots of turning though).
I was somewhat worried about the blood sugar level, which could attribute to the short Deep Sleep minutes.
My respiratory rate continued to be low at 15.8/min, which seems to prove my hypothesis that fasting reduces the body’s need for oxygen.
Blood Pressure
After the temp increase of BP on Day 2, the levels went right back down, especially the diastolic number (lower number), from 77 to 58. This is well expected as researches have proved that long fast can lower blood pressure in a statistically significant manner (1,2).
It is well known that high insulin level is a key risk factor (at least in an associative manner) for high blood pressure (3). Fasting definitely lowers the level of insulin, thus having a beneficial effect on BP.
It is also interesting to note that I have definitely increased my salt, thus sodium intake over the fast. However, this does not seem to have an adverse effect on my BP. There have been so much misunderstanding about salt, similar to those around fat, both being scapegoats for sugar. I recommend a great book on the importance of salt, The Salt Fix.
Breaking Fast
Given the low blood sugar level, I decided to end my 2020 fast on Day 3, making the total fast of about 72 hours.
While I was not that hungry throughout the fast, I definitely missed foods. So I was looking forward to some home-made chicken soup. I went our in the morning and bought an organic chicken and ingredients for the soup, including onions, carrots as well as celery.
When it was time, I broke my fast with a bowl of broth first; it was really yummy with the umami flavor from the chicken and sweetness from onions and carrots. I savored every sip of the broth. After 30 mins, I was ready to enjoy my 2–hour cooked chicken; it was DELICIOUS!
While I did not feel it right away, I did overeat a little bit, making my stomach discomfortable for a couple of hours. The lesson for next time is eat only half full when breaking a long fast.
