[The Fast Life] Conclusion

I didn’t eat for 7 days, lost around 7 lbs and I didn’t die, I swear. Honestly, it wasn’t that bad. I’ve definitely been more hungry and have had bigger cravings at other times in my life. But I’ve also been more focused and had better clarity at other times, so it wasn’t just rainbows and roses.

Let’s look at some data:

Daily Journal

A commonly reported experience during a fast is increased mental clarity. I wanted to test this out but I knew simply making note of whenever I felt “clear-headed” would taint my results with selection and confirmation bias. To test this properly I decided to evaluate my mental state every 2 hours along 5 parameters: Focus, Restlessness (fidgeting), Eye-lid Heaviness (drowsiness), Head Heaviness and Cravings. I find that these five parameters vary independently and can completely describe anyone’s mental state on a day to day basis. I gave these a rating out of 5, with 5’s and 0’s only given out to describe a feeling that was extremely unbearable or usual.

Saturday and Sunday were my adaption days. Without carbs, your blood sugar will drop, but ketone production is not initially high enough to pick up all the slack. This results in an in-between state where both are relatively low and you feel like crap. Amazingly, I didn’t feel that bad, possibly due to being carb-free the week prior, or possibly because I was sipping on some exogenous ketones (KetoCaNa) throughout. In any case, I got through the weekend without a scratch and made it to Monday morning, which is when the real experiment took place.

My monotonous work week provided the ideal experimental grounds to reduce noise and collect data. To ensure that Monday to Friday was the exact same I tried to follow this general procure:

  • 6:00am: Wakeup, take blood and weight measurements, rate mental state
  • 6:45am: Take potassium, magnesium, fish oil
  • 7:00am: Leave for work
  • 7:30am: Arrive at work and make coffee
  • 8:00am: Rate mental state
  • 9:00am: Start drinking Ketone supplement (1 scoop KetoCaNa in 1 cup of water)
  • 10:00am: Rate mental state
  • 12:00pm: Rate mental state, walk for 30min during lunch break
  • 1:00pm: Make second cup of coffee
  • 2:00pm Rate mental state
  • 4:00pm: Rate mental sate
  • 5:00pm: Go home
  • 6:00pm: Rate mental state and then take a 20min nap
  • 6:30pm: Go for a 30min walk
  • 7:00pm: Try to do something creative
  • 8:00pm: Rate mental state
  • 10:30pm: Rate mental state
  • 11:30pm: Go to sleep

Here’s how each day differed:


I woke up Saturday with decent energy, probably because I finally had a chance to catch up on missed sleep. I went to my DEXA scan appointment at around 11 and didn’t feel hungry or have cravings leading up to the scan but I did find myself being irritated easily. After the scan I started walking. I started at 12:30 and didn’t stop untill I hit a starbucks a full four hours later, only sipping on my ketone drink and a coffee I bought half way through. Apart from my shoes being ruined (I really should have worn running shoes rather than boat shoes like a dunce), the walk was quite pleasant and surprisingly not at all boring. For some reason I’ve always found walking far more engaging than, say, running for even half the duration, with or without donning headphones. As you can imagine I got quite tired after the walk. This can be seen in the below graph as the yellow and green lines (head-heaviness and eye-heaviness) crept up, peaked at around 6, and then plummeted when I had a nap. The only other interesting thing to note is that I got really restless before bed for some reason.




Sunday was more or less spent lounging. I did a 30min walk in the afternoon but other than that I was mostly in my bed watching TV shows. Cravings came in mild bouts but not at all unbearable. I noticed I had a runny nose near the end of the day.



Here we go: First day at work. As you can see from the graph, I woke up clear headed but groggy and mentally muddy. This didn’t clear up until I made a coffee at around 9. I took my first sips of KetoCaNa at around 10 and interestingly, almost immediately after, my legs were bouncing like they were made of springs. I should note that I usually experience high restlessness and fidgeting after eating low glycemic foods as if my body is trying to “dump” the excess calories it can’t store by fidgeting, so maybe that’s what’s happening here. Runny nose persisted all day.



By 2pm that persistent runny nose turned into a full-on waterfall, complete with sneezing and nausea. Immediately afterwards, however, the cold symptoms completely vanished for the rest of the week. I had always read about “keto flu”, a condition brought on by a lack of minerals while on a ketogenic diet, but never thought it would manifest as actual flu symptoms. Or perhaps my immune system was subpar and I just had a regular cold? Either way, the rest of the day was decent and I got a solid hour of walking in.



Woo! This was by far the best day of the week. Despite struggling to peel myself off my bed in the morning, the day was fantastic. I mean look at that graph! Sustained high yet calm clarity, low drowsiness and fatigue and pretty much no cravings after 10am. I was feeling so good in the evening that I decided to skip the walk because I figured it wouldn’t be of any further benefit.



Oh, dear. This was by far the worst day of the week. I nearly fell asleep at my desk at around 9am (this wasn’t captured on the graph because I only took readings at 8am and 10am when I was more awake). I didn’t go for a walk at lunch time because of a work constraint. Perhaps that was a big mistake. By the time I got home I felt absolutely dead. I didn’t go for a walk because I didn’t want to get out of my bed. I just felt horrible and could barely even think properly. Maybe walking is the crucial variable in all this. I had skipped three scheduled walks in a row and it’s almost like my body went into hibernation mode.



Ok, much better, but not as good as Wednesday and quite foggy throughout. There was also this headache the persisted for the entire day that I couldn’t quite get rid of. Despite not eating for seven days I had almost no cravings, but still I missed food, or perhaps I missed the endorphin rush of eating something delicious. I went to sleep at night and dreamt of what I was going to eat the next day.



I averaged up all the values for each day and plotted it on this graph below. Here you can see that focus did not waver drastically through out the week.

Qual Meas 2


A DEXA scan (or a Dual-Energy X-ray Absorptiometry scan if you want to sound pretentious) measures body composition and is supposedly one of the most accurate ways to measure fat on the body. I thought this week would be a good opportunity to test this out because conventional methods of measuring fat loss would have error margins far too high to make any conclusions by the end of the week. These two pictures below cost me $240. Please look at them for more them a second.

1 DEXA Image

Notice a difference? Yeah, me neither, initially. If you’re really good at those spot-the-difference games you might notice the yellow fat blobs beside my hips have reduced by the slightest amount. You have may also noticed the gap between my legs was wider and my left leg has gotten… longer?? Don’t worry, the radiation from the scan wasn’t enough to make me grow my limbs (although I would have welcomed it if only it was mirrored on the other leg). The constraints when lying on the scanning table were very minimal. The technician literally just told me to lie on a painted line while she loosely fastened a belt around my ankles. Because of this, it’s hard to conclude just by visual inspection that I did in fact lose that bit of fat around my thigh or if my leg simply was rotated more, allowing more muscle to be exposed and more fat to be tucked away. The DEXA scan works by obtaining a 3D pixel column and resolving it into a 2D pixel from the majority constituent. For example, if you place a 1″ steak on the table and then placed a 1.5″ piece of lard on top, the machine would think you placed a 2.5″ piece of lard on the table. This highlights an interesting disadvantage of the self-proclaimed “gold standard in body fat measurement” that I didn’t realize. Also, considering everything, the resolution isn’t really that great. Good thing I have some numbers to back up the crude cave paintings.

According to the numerical results page I received, I lost about 7.5 lbs. So where did it all go? The scan measures three areas: Your legs, your arms and your “trunk” (which is anything that isn’t your legs, your arms or your head). These were sectioned as per the white lines in the above pictures, and as you can see, they were measured for both right and left body parts but were insignificantly different so I just combined them both and threw them on this nice little graph:

Mass Change 2

Wait, wait…what? Two things immediately jump out at me. Firstly, what in tarnation? I actually GAINED fat on my legs? Hmm, and gained muscle as well. “Sherlock, is it possible that your molecules migrated south?” “No Watson, you dunce, I probably just sat further down on the table.” It’s far more likely that these are errors that arise from not being able to control my body’s place under the scan accurately. The white lines on the scan that separate the different measurement sections were literally drawn by hand by the technician. That being said, I have read studies where people actually increased their muscle mass during a fast. But fat mass? Not so much. You can interpret the data however you want but my interpretation is that a portion of the trunk measurement went into the leg measurement due to incorrect body placement or sectioning. I’m going to assume leg fat and lean mass changes are negligible and that trunk changes are respectively 0.4lb and 0.1lb lower than what is shown.

This leads me to my next astonishing finding, trunk fat loss is 3lb and lean mass loss is 4.6lb! But wait a second, what does “lean mass” mean anyway? After reading up on how DEXA imaging works, I realized that “lean mass” is not simply muscle. The DEXA machine can only measure two things: fat and bone. Anything that is not fat or bone, it considers “lean mass”. The muscle groups contained in my “trunk” would include my abs, core, chest and back. So is it possible that I lost muscle in, say, my chest and back while my leg and arm muscles stayed preserved? Why would muscle loss be so arbitrarily selective? I have a couple of alternative theories: Firstly, maybe I just got a really good power wash of my intestines. Fiber and bacteria are not fat or bone and would therefore show up on the scan as lean mass. Another source of mass loss could be through autophagy. As stated in the preliminary post autophagy is the great recycling program of the body that gets activated during heavy protein restriction or fasting. Damaged cells, useless amino acids and even dead bacteria are recycled for new parts. I’ll admit, I don’t know exactly how it works but presumably what can’t be reused gets thrown out, right? But did 4.5lb of unusable dead cells get thrown out? That seems excessive. Or maybe I just lost a lot of my back muscles. That’s definitely possible but I’ll have you know I went back into the gym after the fast and was able to pull the same weight on the rowing machine as before. I like collecting data but I’m definitely not qualified to interpret it properly. Hopefully someone smarter than me can figure where the 4.5lb went.

Weight and Circumference

Weight and Circ

Every morning at 6am, I got out of bed and measured my weight and my stomach circumference. The circumference was taken on a horizontal plane 1″ below my belly button such that it would also include my love handles at their greatest thickness. I did the same two measurements at 6pm which is why there are four lines on this graph. First of all, it is interesting to note that there was even a difference in morning and evening measurements despite not actually eating anything. I’ve measured myself like this previously under normal conditions and got similar results but always thought the discrepancies were due to the food I was eating throughout the day. With the exception the initial Saturday, I was lighter and skinnier every day in the morning compared to the evening. Perhaps this is due to all that water I was sipping on all week. After an 8-hour water fast (AKA sleep) I hydrated myself until my next evening weigh-in, which, despite my frequent bathroom breaks, may have made my body store enough water to make up the difference. Although, this wouldn’t explain the initial Saturday circumference spike in the evening. I must have lost a ton of weight by 6pm that day because that was after I went on a four hour walk, as evidenced by my corresponding weight measurements the same day.

Just for fun, I lost 6.6lb total from Friday to Friday and 3cm off my belly. I estimated in a previous post that I would get abs at around a 74 cm circumference. So if I continued this for another couple months I’d weigh just over 100 lb and be fully equipped with a malnourished 6-pack… I mean, assuming I survived of course.

Blood Measurements

Blood Meaurements

When I woke up I took blood sugar measurements at 6am and then in the evening at 6pm I took blood sugar and Ketone measurements. It’s interesting to note that my morning and evening glucose was different and fluctuating until Wednesday when they both converged at around 3.7mmol/L. I have not a clue what it means but it is beautiful none-the-less. In order to prep for this fast I went a week without carbs, which is why you can see I already started with non-zero ketones. From there it rose to as much as 6.4 on wednesday before coming back down. This is certainly the highest I’ve ever recorded. It’s true I did drink a ketone supplement but that was at 8am in the morning, a full 14 hours before I measured my ketone levels.

The Glucose Ketone Index (GKI) in blue is simply the glucose value divided by the ketone value. Yale professor Dr. Thomas Seyfried showed that the GKI value can play a huge role in cancer management, especially when it hits the ideal value of 1. It’s hard to see from the graph but I hit GKI of 1 by Monday and it sort of leveled out at 0.6 for the rest of the week.

Nutrient Deficiencies

I have this spreadsheet that calculates what vitamins and mineral you are deficient in if you input what you ate that day. Just for kicks I put in the one multivitamin I was having every day and this is what it spit out:

Calcium: 30% of RDI (Recommended Daily Intake)
Iron: 75% of RDI
Magnesium: 21% of RDI
Phosphorus: 0% of RDI
Potassium: 0% of RDI
Sodium: 0% of RDI
Fluoride: 0% of RDI
Vitamin A: 33% of RDI
Vitamin D: 80% of RDI

But wait a minute, the ketone supplement I was taking was called Keto CaNa because the ketone molecule was bound to Calcium (Ca) and Sodium (Na) and had 1.15g and 1.3g respectively per scoop. The one scoop I had every day fulfilled my daily requirement of Calcium and Sodium. I also had a Magnesium and a Potassium supplement every day, got lots sunlight and plenty of fluoride-filled tap water. So all said and done, despite not eating anything for a week, I was actually only deficient in phosphorus, Vitamin A and a little bit of iron. So really the deficiency list should look like this:

Phosphorus: 0% of RDI
Vitamin A: 33% of RDI
Iron: 75% of RDI

For comparison, this is what you are deficient in if you have three Big Mac meals a day:

Calcium: 82% of RDI
Magnesium: 65% of RDI
Potassium: 69% of RDI
Manganese: 96% of RDI
Selenium: 2.5% of RDI
Vitamin A: 0% of RDI
Vitamin E: 32% of RDI

It’s really quite amazing how much a multivitamin makes a difference. They get a bad rap because they’re pretty useless (and maybe even harmful) if you already 3 healthy meals a day, but for people on low calories diets it should be considered absolutely crucial.


When I tell people that I did this fast they usually tell me something along the lines of “I wouldn’t last a day, let alone seven!” It’s true, someone who is used to having three well balanced meals a day for his whole life might struggle to go a whole day without eating, but this is only because they are introducing their body to a drastic change. Dealing with famine is in our genes. We have backup plans. Most people don’t give their bodies enough credit for adapting to extreme circumstances. That being said, I have been doing intermittent fasting and low carb diets for a few years now so maybe my body is better at adapting than the average person. YMMV. The prep I did in the introductory post is a decent guide but I can’t grantee the same results. I lost a decent amount of weight and it wasn’t the worst week of my life. Having the flu is much worse. Going to work hungover is far more insufferable than going to work on a 7-day fast. My coworkers didn’t even notice I hadn’t eaten anything the whole week.

So would I do it again? I think so, but not anytime soon. You can get into ketosis by just by avoiding carbs and you can get a lot of the benefits of fasting from time restricted eating. I guess I just wanted to see if it was possible. As a weight loss technique, there are far more sustainable methods, and as a will power exercise, I can think of far more grueling tasks. However, if I do decide to go through with this again, I’ll make sure to keep walking. If I could pinpoint a downfall it would be the day I skipped my my walk, which snowballed into subsequent missed walks.I always knew exercise plays a role in metabolism but the effect seemed even more enhanced during the fast.

Anyway, that’s that. Another year, another experiment done. If you want to play around with the raw data I took let me know and I’ll send it to you. And if you want to spend a week of your life foodless like I was crazy enough to do, then I wish you all the best.

Happy Fasting.






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