Fast – day#3

Weight: 80.2
Body fat: 26.6%
BMI: 25.6
RHR: 58bpm
Sleep: 7hrs 21min
BP: 124/76 @77bpm


I’ve decided to only post once a day – at the end of my day. I figure you don’t need to get two of these posts a day. Given the quality of my writing and my deteriorating mind and manners, one post a day is more than sufficient.

I’ve now lost exactly 3kgs in two days. That’s about on par for me, based on previous fasts I’ve done. I usually drop off that much in the first couple of days. It’ll slow up soon.

More importantly my BMI (25.6 this morning) is edging closer from Overweight (BMI above 25) to Normal weight (below 25). The way I’m going I should be below 25 by the end of the week. Interestingly, my blood pressure has come down quite a bit. It was high yesterday – it’s normal today. As I say, I have a pre-disposition to high blood pressure.

Even though according to the sleep app I had more than 7hrs sleep last night, I felt tired this morning on waking. I know the sleep app registers you’re “sleeping” when you’re just lying still in bed. I did a lot of that in the middle of the night last night.

I’m writing a new screenplay at the moment, and night time is my most fertile time for creative thinking. I stayed awake for several hours last night figuring out the next section of my story. I probably had about 4½ – 5hrs sleep.

But now I’ve had my two double espressos so I’m okay!

3PM – Now towards the afternoon of day#3, the hunger is starting to diminish. I’m feeling a bit light-headed but that could be because of the disrupted sleep. A few hours ago I had to go food shopping for Jennifer. I boldly and gallantly walked passed all those yummy foodstuffs that ordinarily I would have grabbed for a big nosh-up later.

Here is the next section of Dr Fung’s book – The Complete Guide to Fasting – that I want to share with you: The five stages of fasting…

The transition from the fed state to the fasted state occurs in several stages, as classically described by George Cahill, one of the leading experts in fasting physiology:

1. Feeding: Blood sugar levels rise as we absorb the incoming food, and insulin levels rise in response to move glucose into cells, which use it for energy. Excess glucose is stored as glycogen in the liver or converted to fat.

2. The postabsorptive phase (six to twenty-four hours after beginning fasting): At this point, blood sugar and insulin levels begin to fall. To supply energy, the liver starts to break down glycogen, releasing glucose. Glycogen stores last for approximately twenty-four to thirty-six hours.

3. Gluconeogenesis (twenty-four hours to two days after beginning fasting): At this point, glycogen stores have run out. The liver manufactures new glucose from amino acids in a process called gluconeogenesis (literally, “making new glucose”). In nondiabetic persons, glucose levels fall but stay within the normal range.

4. Ketosis (two to three days after beginning fasting): Low insulin levels stimulate lipolysis, the breakdown of fat for energy. Triglycerides, the form of fat used for storage, are broken into the glycerol backbone and three fatty acid chains. The glycerol is used for gluconeogenesis, so the amino acids formerly used can be reserved for protein synthesis. The fatty acids are used directly for energy by most tissues of the body, though not the brain.

The body uses fatty acids to produce ketone bodies, which are capable of crossing the blood-brain barrier and are used by the brain for energy. After four days of fasting, approximately 75 percent of the energy used by the brain is provided by ketones. The two major types of ketones produced are beta-hydroxybutyrate and acetoacetate, which can increase over seventyfold during fasting.

5. The protein conservation phase (five days after beginning fasting): High levels of growth hormone maintain muscle mass and lean tissues. The energy for basic metabolism is almost entirely supplied by fatty acids and ketones. Blood glucose is maintained by gluconeogenesis using glycerol. Increased norepinephrine (adrenaline) levels prevent any decrease in metabolic rate. There is a normal amount of protein turnover, but it is not being used for energy. In essence, what we are describing here is the process of switching from burning glucose to burning fat.

Fat is simply the body’s stored food energy. In times of low food availability, stored food is naturally released to fill the void. The body does not “burn muscle” in an effort to feed itself until all the fat stores are used up. One critical point to underscore is that these mechanisms are entirely natural and entirely normal. Periods of low food availability have always been a natural part of human history, and our body evolved mechanisms to adapt to this fact of Paleolithic life. Otherwise, we would not have survived as a species.

There are no adverse health consequences to activating these protocols, except in the case of malnourishment (you should not fast if you’re malnourished, of course, and extreme fasting can cause malnourishment, too). The body is not “shutting down”; it’s merely changing fuel sources, from food to our own fat. It does this with the help of several hormonal adaptations to fasting.

4 thoughts on “Fast – day#3

  1. And which of these profiles were you, Bill, at the start? Really interesting stuff to learn about, so thanks for sharing 🤗


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