My 7 Day Water Fast — Part 4— The Aftermath…

Was I able to work, work out, live socially and go about the day as I am used to?
YES is the short answer, and for the long one, you’ve got to read the rest! ;)

As I said, the answer is yes, but that doesn’t hold on all fronts. There was ever-present cold, energy troughs at around midday, then peaks in the evenings, saved time by not eating though, different mental focus, and especially in the second half, I was losing my appetite for women…

If you are interested in my reasons for this undertaking check my first blog or if you want to know what steps did I take before the fast to make it easier read my second blog.


How did I break it?
How were my performance and mood affected?
How much strength did I lose?
How much weight did I lose?
How much muscle/fat did I lose?
What changes did I notice?
How did it affect my hormones?
How did it affect other blood markers?
Other questions
Some thoughts on food…
Going beyond the fast
What else are you interested to know?
What do you want me to try next? Tell me:


How did I break it?

With fresh green veggies + lemon

Reintroducing the smells

An interesting idea that I think could have a lot of merit is to try to smell the food for some time before you start eating. It should make your gear start running again.

Thinking of food

Strangely enough, I believe that thinking of starting to eat on my last day of fast could have played some role. On the morning of refeeding, I felt my stomach starting to work again.

And now it begins…

I broke my fast after 7 days and 20 hours with fresh veggies. Reading about the problems Damian faced breaking his 10 day fast, I decided to learn from his mistakes and start with raw green vegetables. He went with smoothies, but after some consideration, I decided to chew the food up, as it strikes me as more natural. Then the whole food machinery started running, and I was back in the game, Big time! I had raw sushi an hour later, vegetable soup two hours later, fresh shrimp morning rolls 2 hours later and finished it off with a grilled salmon I had for dinner at ~7 pm.

Happy ending … almost

tip: Do not eat what you find in the fridge after 2 weeks ;)

Full of food, my body&mind wanted to run&eat non-stop. Not being able to fall asleep, I started reading and eating. I found some nuts and some food still left in the fridge. A nice bottle of conserved sour cherries, tasted a bit funny, but hungry as I was, I didn’t pay much attention to it.

Long story short, they had gone sour, and I was recovering from this experience for the next 3 days. It is a great irony that the least productive days came after the fast and were caused by something as trivial as this.

How were my performance and mood affected?

They weren’t significantly worse or better, as far as the tests can tell, but a bit different…

To be able to perform my everyday routines and not be hindered in my activities was my main objective in this fast. I knew about its therapeutic benefits before but hadn’t tried it, as I didn’t want to sacrifice a week of my time.

I tested this in several ways. I noted how energetic I felt 5 times a day and also did a cognitive test 3 times a day. I did this 1 week preceding the fast to get the base values and then during the fasting.

With the help of my friend Michal, a statistician, I was able to see if there was any significant change in my energy and performance — measured by my self-assessed reports 5 times per day and cognitive tests respectively.
And there wasn’t. That was a bit surprising to me, because I had times when I felt quite a sharp energy drop. However, it usually didn’t last for more than 2 hours, and the truth is, I sometimes experience this on my regular days, too.
For those interested, I provide a screenshot of my results at the end of the article.

I also noticed, and was proven right by the statistics, that energy level and mood are interlinked. Since my energy levels were generally good, so was my mood. I noticed no significant difference for the better of worse when compared to my regular days.

How much strength did I lose?

None, surprisingly, but I wouldn’t try running a marathon ;).

Did I loose max strength ?


I tested my max strength with 2 exercises. 1 time max bench press and 1 time max pull up.

Bench press
To tell the truth, I didn’t really expect this, but I did not lose any maximal strength. I benched 81,5 kg on Sunday, the last day of my fast, which was exactly the same as on Sunday the week before. To make sure of this, I repeated the bench again, with the same results. What really persuaded me, though, is the fact that other tests were telling a similar story…

Pull up
The belt that I used for pull up weighted 37.5 kg on the last day, compared to 35 kg on the first day. Don’t get too excited, I didn’t really grow stronger. After I factor in my weight loss, which was 3.5 kg (78.7–75.2), it is 1 kg less. In the hindsight, I would have tried the exact same weight, but I didn’t know what my exact weight loss was at that moment. But then, 1 kg only transfers to 2.7% difference.

Did I loose endurance strength?

Not really, but…

I tested my endurance strength by climbing a rope and doing hand stand push ups. One is a “pull” while the other is a “push” exercise, as in the previous strength test.

Rope Climbing
I didn’t lose much endurance strength, either. I climbed even a bit higher at the end than at the beginning. A fact is that I was lighter, though. Had I had the same weight, I probably wouldn’t have climbed the same hight, but still, not bad when you consider I hadn’t eaten anything since before my testing a week before.

HSPUs — Hand Stand Push-ups
I was able to make 2 more hand stand push-ups after the fast (9 vs 7) as you can see from the video. You can also notice that even though I was able to do more of them at the end of my fast, I needed to rest much longer between separate push-ups (30s before vs 50s after). My take on this is that my max strength really didn’t change; more reps because of less weight, but what did change was my stamina. I felt considerably more exhausted as you can see from the video.

On the one hand, one can argue that this endurance strength testing wasn’t that rigorous, since I was 4.5% lighter. On the other hand, if you are trying to maximize the strength to weight ratio, it does make sense.

How much weight did I lose?

3.5 kg lost, gained 200g from 3rd to 4th day!

I weighed myself every morning upon waking up, after depleting the excess liquids from my body ;) and here are the results. Not receiving any calories, I lost 3.5 kg during the fast. Not that much for not eating for a week in my opinion. If you were to try something like this without preparation, you would probably lose much more. The truth is, I lost more the week before the fast than during the fast itself.

Losing weight

82.5 kg -> 78.7 kg -> 75.2 kg

I had 82.5 kg a week prior to fasting when I started my pre-fast diet I talked about in my second blog. So I lost 3.8 kg to 78.7 kg before the fast and then another 3.5 kg not eating anything for a week to 75.2 kg, which my scale showed the next morning after fasting. One interesting thing I noticed is that my evening and morning weights sometimes differed by as much as 1 kg or even a bit more. What is even more surprising, I actually gained 0.2 kg on the 4th day. Not sure if my body actually retained more water on that day, or if there was simply an error somewhere in the process.

Gaining it back

75.2 kg -> 78.4 kg -> 82.4 kg
Tip: Do not eat canned sour cherries that you find laying in the fridge — does not help with your digestion ;) — tested.

My purpose for this fast wasn’t to lose weight, and I would not recommend it for that purpose, either. Yes, you will lose weight, mostly water and fat, and it could be a significant amount, but if you go back to your same routines after it’s over, I can guarantee you, you will be back at the same weight in no time. Unless you start off the first day by eating old sour cherries as I did.
Despite the digestive problems that followed 2 days after finishing the fast, I gained the weight I lost in the fast in a week and got back to my usual weight within a month.

How much muscle/fat did I lose?

Belly fat disappeared, surprisingly almost no muscle loss.

Muscle loss
There definitely was some muscle loss. I saw this mainly indirectly from markers in my blood test that I had done the next morning after my strength test. However, if you look at the graph or the video above, the changes aren’t that big. My subjective feeling was similar. I was surprised I did not lose more, and what I did lose, I attribute mostly to my workout trainings. This could be partly explained by the high ketone levels, which possess strong anti-catabolic properties.

Fat loss
I have never had such a six-pack as during this fast. I was definitely much more chiseled. Fasting was in vogue for fat loss in the 50s and seems to be remarkably good for that.

What changes did I notice?


This is a bit irritating about fasting. When your body machinery encounters low energy state, it starts to save energy and letting your limbs cool off is one of the easiest things to do. This was a bit annoying at times, but I just put another layer on, and problem solved.

Does low blood glucose or fast itself make me cold?

Finished with fasting, I was testing the effect of different supplements on my ketone levels (eating medium carb diet at this point). When my ketones suddenly spiked and caused my glucose to drop I felt sudden cold take over. It wasn’t the fast and neither high ketones, as they were not really high compared to my fasting levels.

Ketones have the effect of driving glucose down, and when my glucose dropped significantly (more than 1 mmol/l), I experienced sudden cold.

Missing food

No, I wasn’t hungry but I really missed the social aspect of food that I perhaps didn’t realize fully before. Also to enjoy a nice bloody steak or your other favourite food, is pure pleasure. Even though I was not hungry I did miss it! Along, with good sleep, sex and social contact, it is one of the primal pleasures that we big-brained mammals inherited and should enjoy.

Back pain

It started 1 day before my fast, and I am not really sure what the exact reason was. The pain was in my lower back area, and it wasn’t unbearable but inconvenient. It got progressively worse, not to the point of limiting me in my daily activities, but definitely made me conscious of my sitting habits. On the third day, I found what the trick was and how to reverse it. I needed to consciously contract my core muscles and keep them so. After I got used to it, the back pain slowly went away.

My hypothesis would be that either my involuntary muscles weakened or became less stimulated, or simply not having any food in my stomach made the trick. If you have any ideas, suggestions or thoughts as to why this happened, I will be very glad to hear them.

High energy

I have to say I was surprised. I didn’t expect to have so much energy as I did, taking into account my previous fasting experiences and the fact of not giving my body any fuel for a week. I had a couple of troughs in the middle of the day but was usually very vibrant and alert towards the evening. Neither the cognitive tests nor my self assessed energy levels showed any significant differences, before and during the fast.

Surprisingly little weight loss

Which is a good thing for me. I only lost 3.5 kg. For more, check the “How much weight did I lose?” part of this article where I delve into more detail.

How did it affect my hormones?

Fasting is not a good honeymoon practice ;).

I have also noticed, what other people have documented. A significant drop in my testosterone, thyroid hormones while SHBG (Sex hormone binding globulin) skyrocketed. I did my blood tests 1 week before fast, at the beginning, at the end and 1 month after.


went down

Testosterone is important, but the dealbreaker here is free testosterone, which is bio available (it can be used by the cells). Even though my testosterone levels were at the higher end of the spectrum — 26.4 nmol/l — a week before my fast, because of high SHBG levels, the free form was in the lower range — 10.6 pg/ml. Paradoxically, a week before the fast, my libido didn’t drop — if anything, it only increased. Then during the fast, it slowly waned as documented by testosterone level of 3.08 nmol/l just after the fast.

Strong rebound after the fast
1 month after I finished the fast, my testosterone levels were well up above the normal range at 31.6 nmol/l — 19% increase, but what’s much more important, my SHBG levels dropped way down into the mid-range values — 65.6, that is 35% drop from the value before the fast and 55% decrease from the value at the end of the fast! That showed up in the increase of my free testosterone. It was 10.6 pg/ml one week before the fast, and 15.89 pg/ml one month after the fast. That is a 50% increase in free testosterone!

I cannot say though that this is completely due to the fast as I started to supplement things that I was deficient in — Vitamin D and Omega 3 right after I finished fasting both of which should have positive effects on testosterone levels.

SHBG (Sex Hormone Binding Globulin)

went up — probably due to low carbs/calories

In case you are wondering what SHGB is and why it is important, this hormone binds testosterone and renders it unusable for other cells. Even high levels of testosterone don’t necessarily translate into reality if SHBG is also high. After all, this is also my case.

In my case, SHBG seems to rise due to either low carb intake or low calorie intake, possibly both, but not due to the fast itself.
I have deduced this from the fact that my SHBG levels were already elevated 1 week before the fast — 101.1 nmol/l — when I was following a low carb diet, and then after following a strict low calorie ketogenic diet for a week, they rose to 156 nmol/l, at which point my fast began. The test at the end of the fast shows, SHBG plateaued there. Right before starting to eat again, it was at 145.66 nmol/l.

Thyroid hormones

TSH+Free T3 went down, Free T4 went up

My thyroid hormones are normally at their lower range of the normal spectrum, which might be partly due to my relatively low carb intake and partly to genetic predisposition. I am not sure what effect these hormones had while fasting, besides lowering metabolism — a desired outcome, but will share the results for those interested.
My results 1 week before the fast and at the end of the fast respectively were:

0.99 -> 0.88 mIU/l
Free T3
3.21 -> 2.34 pmol/l
Free T4
9.5 -> 11.41 pmol/l

How did it affect other blood markers?

Glucose + Ketones

The lowest glucose level was 2.6 mmol/l and the highest level of ketones was 7.2 mmol/l. My daily glucose and ketones movements can be seen in my daily blogs.

A general trend I saw was a gradual increase in ketones from the morning toward the evening. Also, my glucose levels rose sharply whenever I worked out, which is understandable, since I did a gymnastic workout. It is a strength oriented anaerobic exercise which requires sugars, as only those can be used as a source of energy when there is a lack of oxygen in cells.

Uric acid

I had had problems before with elevated uric acid. Therefore, I watched this marker closely. It shot up before the fast after the week of a strict ketogenic diet, then a bit higher, but plummeted well into the normal range after the fast had finished.
1 week before — 352 μmol/l -> Fast starts — 469.2 μmol/l -> Fast ends — 490 μmol/l -> 2 weeks after — 285 μmol/l


It really soared during the fast from 19.02 to 30.21 μmol/l. However, 2 weeks after the fast when I repeated the test, it went back to normal mid-range — 10.8 μmol/l.


Chlorides dipped a bit below the normal range during the fast and came back to normal right after. They went from 99.3 mmol/l before the fast to 93.2 mmol/l after the fast. However, they came back to their normal range — 102 mmol/l — two weeks after the fast was over.

Vitamin D

Vitamin D levels actually improved during the fast. I was really deficient before the fast — 64.9 nmol/l, which rose to 96.96 nmol/l after the fast. This could be due to the release of vitamin D from adipose tissue (body fat) during the fast and perhaps partly to other effects of the fast.


Zinc was already high at the beginning — 18.03 μmol/l — and it slightly increased and topped the normal range — 20.12 μmol/l — after the fast.

CRP (C-reactive protein)

One of the main inflammation markers decreased dramatically from 1.09 mg/l before the fast to 0.26 mg/l after the fast as expected.

Erythrocytes sedimentation

Another inflammation marker changed for the better, where before the fast it increased from 3 after 1 hour to 5 mm/h after 2 hours, and after the fast, it remained the same — 3 mm/h both after 1 and 2 hours.


Homocysteine was elevated and seems to be affected by the fast very little if at all. It was at 13.93 μmol/l before the fast, improved a bit to 12.05 μmol/l after the fast, and one month afterwards, it is still 11.54 μmol/l. I presume that I might have a genetic mutation that causes its elevation or perhaps other personal reason.

Other questions

How much weight and muscle did I lose?

Not much. For more, check the “How much strength did I lose?” and “How much weight did I lose?” parts of this article where I discuss these questions in more depth.

How much/what did I drink?

I drank about 50% more than normal. Mostly water, mineral water, occasionally coffee.

I didn’t measure this exactly, but I definitely drank a bit more than normal. Ordinarily, I drink about 4 liters a day, and during the fast, it could have been 6 liters easily. Mostly mineral water high in magnesium and good magnesium/calcium ratio — 4:1. Then water and occasionally also coffee, once a day. I listened to my body and drank less and less as the fast progressed.

How hungry was I?

A little on the first day, not at all afterwards.

This is perhaps the most frequent question I get. Ironically, it is not the one I would consider important, hadn’t I been asked it a million times, since hunger was not really a problem. I experienced energy drop at the beginning and towards the end but not hunger.

This is a very individual question, though. I have always been very tolerant to going without food when I compare myself to other people. Moreover, I followed a special diet a week prior to the fast which definitely helped me get ready. In the end, I experienced only “regular” hunger that I would normally feel after skipped meal. It was on the first day during the lunch time — the time when I used to have my first meal of the day — and that’s it.

What has always been the main issue, though, is the energy levels. This had been a problem with my previous fasts and something I was trying to avoid.

If you have any other questions, don’t hesitate to ask in the comments below.

Going beyond the fast

This was a major undertaking for me, and I went into it 100%. This led me to do all the different blood tests I had never done, scrutinize myself at a different level and develop a superior self discipline fueled by the sense of a mission.

Improving discipline

As a recovered alcoholic always falls to his bottle of whisky when the hard times strike, so do I remember my fasting when my willpower dwindles.

Whenever nowadays I am losing my willpower trying to rationalize doing something I want to avoid, I always have the trump card at my disposal, and the conversation goes:
I know I told myself no chocolate today, but one piece should definitely be OK, because bla, bla, bla (fill in your favourite rationalisation).
C’mon you have fasted for 7 days, can you really not go without something as trivial as a piece of chocolate for 1 day?

The answer is clear…

Becoming more self-aware

Interestingly enough, as I have become more in tune with and aware of my body, I also am able to detach from it much easier. This metaphor strikes me as fitting:

Once you study the thing you so much feared, the fear vanishes.
My paraphrase would go something like this:
Once I had watched my body so closely, I can distance from it much further.

So the more I am able to deconstruct myself, the better integrated and complete I feel as a person. Instead of I need this!, my narrative now is, my body desires this, which is quite a shift of perspective.

Some thoughts on food…

The fixation

I come from a family, perhaps even a society, obsessed with food.
You have to eat your breakfast! You need to eat at least 5 times a day. And frankly, how many of us use food as a time filler, a way to procrastinate, or as a quick fix to our problems?
What is the reason for it? Is it a trait of the consumer society we live in? Or lobbying of the food companies trying to cash in their bonuses? Or simply a primal urge carved into us by evolving in the environment of frequent famines?
Regardless of the cause the fixation is here.

It goes deep within us

When you want to befriend a stranger, don’t talk about politics, religion and diet.

I have frequently noticed that talks about food are among the most emotionally charged. I am a celiac, and what really stroke me strange when I changed my diet was the pity I received when eating with people who suddenly learned the news. A kind of a sincere worry that people give when a person loses an arm or a leg, which was a bit strange to me, since the diet itself improved my well-being at least twofold.

Also, my impression is that many diets and dietary guidelines nowadays more resemble religious sects with their indubitable dogmas than scientific search for truth.

Separating the need and want

The fast made me realize quite starky how much I used to rationalize the need to eat. After that, I can hardly justify to myself that I really need to eat at most occasions. Also, I believe that I am more true to myself. Knowing I don’t need to eat, it’s a win win situation. Because my discipline is much stronger, I can will myself regarding what to eat or what not to eat. I can also enjoy it much more, since the underlying “necessity” is no longer there. Nowadays, when I am eating, I am really clear about the goal. Do I want to gain weight? Lose weight? Or just enjoy the food?

When I am clear I just want to enjoy the food, I let myself and have much more pleasure from it than before. There is no internal struggle, because I am not trying to sell myself on the idea that it is good for me for any reason other than pleasure itself.

Enjoying the simple pleasures of life

Breatharians claim that they don’t need to eat and live purely from the cosmic energy. No matter how esoteric it may sound, it is a good thought experiment.

If I could perform at my peak without eating, would I do it?

It doesn’t really make much sense. After all, we are pleasure seeking creatures, and the primal pleasures which still drive much of our behaviour, no matter how high and mighty we may feel, are Food, Sleep, and Sex.

Thinking about it, I believe most people’s idea of a good time when you just want to switch off and relax is a couple of nights in a 5-star hotel, with a beautiful girl/boy and great food. Long story short, whatever else is put in the recipe, these 3 ingredients remain.

The cheapest of them all

Food for the indulgence’s sake is the cheapest of all 3. Even the average person can afford a dinner in a Michelin restaurant from time to time. Night in a luxurious hotel is definitely more expensive and adding a high class escort to the mix is really only for the rich.

Not that I could or would put a price tag on everything, majority of us would probably much rather have a beautiful boyfriend/girlfriend than an escort, but it serves well to emphasize this point.

Most of the overweight western world can stand as a living proof to how easy and widespread food indulgence really is.


To my family & friends, for the support without which I would not be able to undertake this project.

To Milan Machalec for data preparation and statistical analysis.

To Veronika Froncová for proof reading, tips and great suggestions, which definitely make the reader a better experience. Less grammar errors for sure ;).

What else are you interested to know ?

I amassed a large chunk of data, before during and after fasting. If you have any questions, concerning anything from preparation, to execution, measurements, blood tests, or anything else, please let me know in comments below.

also if you have something you would like to see tried but don’t want to do it yourself just let me know. I’ll see what I can do.

What do you want me to try next? Tell me:

in comments below
on facebook
on twitter
on youtube


The changes from before to after the fast are quite insignificant, which is quite significant.

before_fast= 0 -> the week before fast, before_fast= 1 -> the week of fast — sorry for the confusing terminology ;)




Passionate about pushing my limits, self experimenting, bio-hacks, complex and distributed systems, mechanism design.

Love podcasts or audiobooks? Learn on the go with our new app.

Get the Medium app

A button that says 'Download on the App Store', and if clicked it will lead you to the iOS App store
A button that says 'Get it on, Google Play', and if clicked it will lead you to the Google Play store
Marko Zelman

Marko Zelman

Passionate about pushing my limits, self experimenting, bio-hacks, complex and distributed systems, mechanism design.

More from Medium

Shiny Object Syndrome — Are you always looking for what’s next?

Why Am I Not Losing Any Weight?

Seven Keys To Achieving A Safe And Effective Keto Diet When Losing Weight

My Calorie-Counting-Obsession Has Impacted My Relationship With Food