My Experiment With Intermittent Fasting

Beginning in Nov 2016, I embarked upon an intermittent fasting experiment to examine what effects, if any, it has on my health and overall well-being. I routinely dive into self-experiments but leave most of them undocumented. This was different because I diligently tracked things I was hoping to impact with my experiment. Here are the results of that experiment.

Before I begin, let’s define a few things first.

What is Intermittent Fasting?

Fasting is taking a break from consuming calories, usually in the form of food that we all eat. By this definition, it is clear that all of us fast daily between the times we go to bed and when we wake up. Fasting, as is commonly understood, though is a longer than typical period of ‘not eating’.

Intermittent Fasting is a diet protocol that intersperses defined periods of ‘not eating’ with regular eating phases. There are many variants – 16/8, 20/4, Alternate Day, 5:2 (Details here)

I have done some of these in the past and in fact, for the best part of the last two years, I have done away with breakfast. My first meal these days is typically lunch, which too has been delayed since then.

For this particular experiment, I was interested in the 5:2 variant, one that was popularized by the BBC Documentary and research conducted by Dr. Michael Moseley.

Why Intermittent Fasting (IF)?

There are hundreds of anecdotal benefits attributed to IF including weight loss, stabilization of insulin & blood pressure and reduced inflammation (read: fewer instances of random fevers and common cold).

Rigorous research, unfortunately, hasn’t been that forthcoming, especially with human subjects. The current consensus is divided and there are differing schools of thought on the impact it has on muscle loss and on special populations (diabetic, elderly and children).

As is the case with research related to nutrition and fitness, every subject is different and there is no way you can recommend something that works the same way for everyone.

But, there is one heuristic I routinely use these days – if it’s worked and has been followed for thousands (not hundreds or tens) years, there is a higher likelihood it has its merits. This heuristic has worked for me wonderfully in other areas – books (I defer to older classics than latest ‘hits’), exercise, philosophical viewpoints and sleep.

Fasting, as a practice, appears to exist in every culture across the world in one form or the other. So, I was betting on it to work more than not.

In my case, there were three objectives:

  1. Decrease body fat
  2. Stabilize my glucose levels
  3. Increase well-being

The Experiment – Protocol, Measurements and Experiences


I planned for this experiment to last for 12 weeks. Each week would involve two non-consecutive periods of 20 hours or more during which I would consume no calories (I revised this later to increase the limit to 500 calories; will explain why). My fast would commence after dinner the previous night and continue until dinner-time of the fast day. For e.g. I’d have my dinner on Monday at 10 PM, go to sleep, wake up the next day and eat nothing until Tuesday, 10 PM. I would break my fast at this time and resume my normal eating routine.

Finer Details:

  • In order to isolate the effects of fasting alone, I paused my lifting program. Also, I wasn’t too sure if I should be lifting in prolonged fasted state, from a muscle loss perspective.
  • On similar lines, I also ate in an unrestricted manner on all non-fasting days including consuming sugar and sweets.


Baseline: I didn’t have a set of baseline blood panel measurements right before I began my IF experiment. Fortunately, because of my obsession with having samples of blood drawn out of me and testing these, I had one that wasn’t too dated. For the purpose of this experiment, I will use these as baseline measurements. These include:

  • Lipid Profile – Trigs, HDL and LDL (relevant ratios)
  • Glucose Profile – Hb1Ac
  • Thyroid Profile –  Total T3, Total T4 and TSH

Ongoing: During the course of the experiment, I tracked my weight, blood glucose (right before I broke the fast) and waist size. I also tracked the calories I consumed, general mood and activity levels. The last two are subjective indicators and not very reliable but I wanted to document these nonetheless.

End-line: These will be a repeat of the baseline measurements, conducted in an external lab.

The Outcome

Summarizing by the objectives I’d set out at the beginning of the experiment, here’s what happened:

1. Decrease body fat: The most important result and outcome. Fat-loss,measured as a combination of weight loss and reduction in waist-size, disappointing. My net weight loss was 1.2% by the time I concluded the 10-week experiment. Because the results were discouraging on this metric, I stopped the experiment at 66 days (10 weeks), instead of the planned 84 days (12 weeks). There were variations through the experiment with the largest loss happening between the 17th and 31st day of the experiment. For some reason, I gained back the lost weight in the subsequent weeks.


One reason could be the modifications I introduced after day 35 when I began having a limited amount of calories on fasting days (like what the original 5:2 diet recommends). This was primarily in the form of whey protein to prevent muscle atrophy. But, protein intake also spikes insulin, which in turn, slows down the fat breakdown process. In hindsight, I was probably more worried than I should have been about muscle loss. Ancestors have survived for days without eating while also being on hunts. A data point that supports this hypothesis is the ‘counter-intuitive’ trend in the chart below (Fig.2) that seems to indicate a higher weight loss on days I consumed more calories. It didn’t matter if I ate 50 or 500 calories on fasting days because even 50 calories in the form of carbohydrates or protein was enough to spike my insulin.


2. Stabilize my glucose levels: The next outcome that I measured was my random blood glucose (technically, fasting glucose) at the end of every fasting period. This was a far more encouraging outcome, with a net decrease of 10%.


Since my body did not have to produce as much insulin on days I fasted, I believe my body’s insulin response was ‘re-sensitized’ so it was able improve the regulation of glucose levels.

Other blood panel results: There was a drop in the HbA1c level, a long-term indicator of plasma glucose concentration. Similarly, my Triglycerides/HDL ratio also fell, a reliable indicator of long-term coronary heart diseases. For the sake of completeness, here’s a quick snapshot of the test results:


3. Increase well-being: An even more significant and positive difference I noticed was a heightened sense of focus and sharpness. On fasting days, this would typically kick in by mid-morning and would persist until late evening. In contrast, on non-fasting days, I would feel lethargic after meals, especially on days I had a heavy breakfast. Since I have anyway been skipping breakfasts for a couple of years now , this has only convinced me to continue with this habit.

If you need more coaxing:  ‘ A surprising number of males (not females) over 45 never eat breakfast, or eat only the scantiest of fare (e.g., Laird Hamilton, page 92; General Stanley McChrystal, page 435)‘ (source – .

From my perspective, this aligned perfectly with stoic beliefs that I have sought to practice more diligently since last year. Depriving yourself of dependencies is one of its key tenets so this fit in very well.


This particular IF protocol didn’t yield significant benefits from a fat-loss perspective. Neither did I lose absolute weight nor did my waist size (a strong indicator of metabolic syndrome), though it improved my insulin response. I did enjoy practicing this protocol, on the whole, because I felt I was sharper and focused on fasting days.

There are, of course, other long-term benefits purported to intermittent fasting such as autophagy, potential reduced likelihood Alzheimer’s Disease, cancers and atherosclerosis, each of this due to the regulation of insulin and insulin-like growth factors (IGF). It isn’t conclusive but given the negligible (non-existent, as far as I can tell) downside and a multiple upsides with a high probability, I can’t see why I should stop following this.

Do you or have you followed a fasting protocol in the past? Do share your experiences here. It will be great to have a wider sample size to examine aggregate effects.


4 thoughts on “My Experiment With Intermittent Fasting

  1. Very interesting results Shreyas. Thankyou for taking time and jotting down your journey. I wonder how the results would look if frequencey is changed to fasting every Ekadashi.

  2. I have been trying IF for a couple of years too, and I always feel a sense of calm after the initial disturbance. My appetite stays in control for a few days after IF.

  3. Been trying the 16-8 kinds on most days, with a cup of bulletproof coffee at the 12th or 13th hour. I also throw in a 1hr run in fasted state. The only time when it troubles me, is on days when I have interval training, done at 80-90% of my heart rate (seeking glucose as a source of fuel).

  4. Murali: Thanks :) Results should look similar though I guess it might take longer for stabilization since the fasting days are spaced out further apart.

    Vishal: Awesome! That’s my plan too to stick with it in the long run.

    Manoj: In fact, it was you who introduced me to the idea of fasting many years back.

    I did the 16-8 fast too for a bit but because the break-fast meals were odd (esp if one is at work), I found the 24-hr fasts easier to manage. The idea of bullet-proof coffee as the ‘cheat’ meal is nice because it’s mainly fat and is likely to not spike insulin. Will try that on fasting days and see if it makes any difference.

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