Last week, I went five full days - Sunday to Friday evening - without eating a single calorie. Am I anorexic? Hopelessly poor? Insane? I can assure you that Iām neither anorexic nor poor.
Itās called water fasting. As the name implies, the idea is to put nothing down your gullet except fresh water for several days or more. Supposedly, this comes with numerous health benefits.
I realise this falls outside much of the conventional wisdom about health. But then, the conventional wisdom about health is why nearly a third of British adults are obese. So who cares what conventional wisdom has to say?
Whatās the point?
The basic idea is that a few things happen when you fast.
Firstly, it encourages a process called autophagy, whose name comes from the Greek for āself-devouringā. This is the bodyās natural process for killing off old and decrepit cells to make room for the new, and itās essential to health.
Secondly, after a few days without food, your body enters a state called ketosis, which essentially means that youāve run out of carbs and start burning fat for energy. This has obvious fat loss implications - although I didnāt do this for fat loss, as I didnāt have much to lose.
More importantly, evidence suggests that periodic fasting can lower your risk of cancer, Alzheimerās, Parkinsonās, and more. I recommend this post by Nat Eliason, which has (among other things) a nice roundup of the supposed benefits and the evidence.
Think about it like this: humans arenāt supposed to eat the whole time. Weāre adapted to life on the African savannah, where there was no guarantee of a steady food supply. Short periods without food are definitely something weāre adapted to handle - and arguably something weāre supposed to experience every now and then.
Plus, numerous friends and acquaintances of mine have tried it, and all reported positive results. The consensus Iād heard is that the first 2-3 days can be tough, but after that itās surprisingly easy. As well as the long-term health effects, you can see major upsides while fasting - the biggest one being an enhanced state of mental clarity.
And finally, itās just plain weird. So of course Iām intrigued. And at the very least,itāll give me something to write about.
Reasons Not To Water Fast
Iām not a doctor. Do your own research before doing any kind of fast yourself, and donāt blame me if something goes wrong. Before I give any kind of advice, there are some obvious ānot to-dosā worth pointing out. Donāt fast (or at least consult your doctor first) if youāre:
Ill or have any major health issues.
Severely underweight.
Pregnant.
Are young and still growing.
Probably some other obvious contraindications that Iām missing.
I fasted for five days; next time Iāll probably do seven. (Some people have done them for a month or more.) If you want to do a particularly long water fast, you should probably do it under medical supervision. A āfasting centreā - yes, they exist - is just a web search away.
Letās be clear about this: people die if they put the wrong things into their body, including ānothingā. If youāre otherwise healthy, a 5-day water fast probably wonāt kill you, but you still need to take this seriously. Do your homework.
Above all, listen to your body. If things start getting really tough, quit! Better safe than sorry.
Common side-effects of a water fast include fatigue, headaches, and muscle cramps. If youāre addicted to caffeine and/or sugar you can expect to feel withdrawal effects from those substances too. You donāt have to throw in the towel at the first sign of discomfort - but donāt force yourself through extreme negative symptoms just for the sake of completing an arbitrary number of days.
How To Do a Water Fast
The basic rules of a fast are this:
Donāt eat anything.
Drink only water.
The devil, however, is in the details. As with anything health-related, no-one can agree about anything, and thereās a ton of contradictory advice out there.
For every article online that advises one thing about fasting, you can find another that advises the opposite. And of course, for every credible-seeming source with the appearance of science, thereās page after page of hippie mumbo-jumbo. (Hint: if it says anything about ādetoxingā or ācleansingā, you can probably ignore it.)
1. Donāt eat anything?
Some sources recommend you supplement with minerals like sodium, magnesium and potassium. These wonāt get your digestion going because they contain no calories, and they can alleviate headaches and muscle cramps if you get them.
I didnāt take any magnesium or potassium supplements, but sodium can be found in regular table salt. When I had a headache on days 2 and 3, I occasionally dissolved a pinch of salt in the water I was drinking. My headaches eventually went away; I donāt know if it was the salt that fixed them.
2. Drink only water?
What kind of water should you drink? Is tap water okay? Or should you only drink distilled water? Mineral water? Holy water? No-one agrees.
In my case, the decision had already been made for me - here in Brazil you canāt drink tap water anyway. I drank water from the filter in my kitchen. (I would have drunk holy water, but it burns my tongue.)
Some say that zero-calorie drinks like tea or black coffee are also acceptable (providing you donāt mix them with sugar/milk/etc.). For the sake of purism I stuck with waterā¦ until day five, when I had a single cup of black coffee a few hours before breaking the fast for real.
So technically this wasnāt a ārealā five-day water fast, but Iām not losing any sleep over it. Well, that coffee did get me way more wired than normal. So maybe I did lose a little sleep over itā¦ but not in a figurative sense.
Thereās also disagreement on how much water you should drink. My solution: I drank whenever I felt thirsty. Which was, āmost of the timeā. While I didnāt take exact measurements, I definitely drank a LOT of water during my fast. As you should.
Interestingly, I felt much less thirsty - and consequently drank less water - on the latter days of the fast than at the beginning. Iāll let the nutritionists speculate as to why this might be the case.
Hunger
Everyone I know whoās fasted agrees on this: after the first day or two, you donāt feel hungry anymore.
To give a not-very-scientific explanation: after your stomach has sounded the alarm for a while but received no answer, it basically gives up. It realises that you need to go hunting and gathering, and itās not in your stomachās interest to cripple you with debilitating hunger pains while you do this.
On days one and two I felt hungry like youād expect, but it wasnāt too bad. It came and went in waves, and it didnāt interfere with my ability to get other stuff done.
On day three I didnāt get hungry at all, although I felt bad in other ways as Iāll describe below. Day four was pretty easy, although my stomach did let itself be known for an hour or two in the middle of the day.
By far the easiest day, in terms of hunger, was day 5. I didnāt feel any cravings or hunger pangs whatsoever. When I broke the fast at 8pm, I felt like I could easily have continued. Itās amazing how little hunger I felt after 120 hours with no food.
For sure, I never felt full. On some level, I was always aware that my stomach was empty. Iād compare it to how I feel on a normal day if Iām slightly late to eat dinner - nothing I couldnāt deal with.
This fast made me aware of the different types of hunger that I feel. Thereās a physical component - grumbling from the stomach - and a psychological one - cravings for the taste of food on my tongue. On days one and two, the psychological hunger was stronger; by day three it had disappeared and physical hunger was more noticeable.
Then thereās the habitual side of hunger. This is the weirdest thing about a fast: on practically every day of my life, Iāve eaten lunch and dinner at roughly the same time. It felt very strange to not do it anymore.
All day, every day, food-related thoughts kept popping into my head, only to be struck down mid-sentence. āHey, maybe I should pop out and get a - oh, right, yeah.ā
This was the hardest thing - skipping meals isnāt just hunger-inducing, itās disappointing. After a solid morning or afternoon slogging away at whatever at is that you do, itās rewarding to take a break and sink your teeth into something succulent. Except now, for the first time in your life, you canāt.
Mentality
I didnāt really experience the enhanced mental clarity that some people report. Days two and five were probably the best, but I never at any point thought āwow! Iām so much more clear-headed than I normally feel!ā.
On the other hand, I did experience some mild headaches on day two. This is a common side-effect, and there are many aspects of a fast that could cause it. Drinking water helped, as did eating a bit of salt.
Then I went to bed on day twoā¦ and woke up with a SPLITTING headache. Combined with a dry mouth, it felt almost exactly like a hangover.
You know when you desperately need water but feel too shitty to drag yourself out of bed and get some? That was my Wednesday morning.
When I did get up, I felt slightly nauseous - again, just like a hangover. I drank tons of water, and took more salt. By about 1pm, my worst symptoms had subsided, but I still felt very foggy and found it hard to concentrate on anything. Day three was, for all intents and purposes, a disaster.
Other days werenāt nearly as bad, but on the whole, fasting was a definite net negative to my productivity. Sometimes I felt clear and focused, other times I felt foggy and couldnāt concentrate. The latter was more common.
With that being said, the focus-to-fog ratio did improve as the fast went on. Day five was my most productive day; day six would likely have been better if Iād continued. This is one reason why Iām interested in trying a 7-day fast next time.
Fasting instilled me with a strange sense of apathy. Iām normally a type-A, āgotta be doing something productiveā, always-on kinda guy, but most evenings last week I was content to just lie in my hammock and stare into space. Iād try to read a book, but the words just wouldnāt go into my head.
On Thursday, after trying and failing to read the same paragraph five times, I gave up and spent the evening playing video games - and I almost never play video games. Borderlands 2 seemed to be the only thing that would keep my brain occupied.
Sleep & Energy
I slept more than normal while fasting, averaging about 9-10 hours each night. Other than that, my physical energy levels didnāt feel very different from normal. Other than the occasional set of press-ups or jumping jacks, I didnāt do any exercise, but I was still able to go about life as normal - running errands, walking around town, etc..
I live on the sixth floor, and my policy is to only take the lift when Iām in a rush or carrying something heavy. While fasting, I upheld this policy. The stairs were more tiring than normal, but they werenāt insurmountable.
Most nights Iād go to bed much earlier than my normal time, even though I wasnāt very tired. āHey, Iāve got nothing else to do. Might as well go to bedā. It was part of the same general sense of apathy described above.
Breath
On day three, I started getting a strange taste in my mouth - sweet, slightly metallic. This is another common side-effect of fasting, and itās a sign that youāre entering ketosis (the state of burning fat for energy instead of sugar.)
The funny thing is, I recognised the taste. I feel the exact same taste in my mouth when I wake up after a particularly heavy night of drinking - especially if Iāve been drinking spirits.
I remember something from when I was 18/19 and still living at home. Sometimes after a night out, Iād be lying in bed feeling sorry for myself and Iād have this same sugary taste on my breath. My mum, who is a doctor, would observe my hangover and tell me - among all the typical parental anti-alcohol admonishments - that I āsmelled of ketonesā.
I had no idea what a āketoneā is, but now I know that itās a type of molecule produced by the breakdown of fatty acids. When youāre in ketosis, you expel ketones when you exhale, hence the taste on my breath.
I still donāt understand what this has to do with alcohol.
Other stuff
Some other notable things that happened (or didnāt) while fasting:
I got slight cramps in my legs on day three. Again, this is a common side-effect. It may be caused by mineral deficiency. Whatever the case, it wasnāt too bad, and it lasted less than a day.
Throughout the fast, I felt very sensitive to cold. Iād sit at my desk wearing my thickest jacket and still be shivering - and Iām in Brazil.
My lips got very dry during the fast. Applying lip balm felt amazing. When you havenāt eaten in days, the smell of anything vaguely food-like is a pleasure.
Some report feeling light-headed or dizzy while fasting. This wasnāt really the case for me; sometimes Iād feel a bit light-headed after standing up, but it wasnāt anything major.
Breakfast (literally)
On Friday, I was practically counting down the minutes until I could eat again at 8pm. The closer it got, the slower time seemed to move.
Some argue that you should reintroduce food slowly when breaking a fast - start with the stuff thatās easy to digest, then slowly work your way up to the tougher stuff like meat. I question this logic, and I didnāt really bother.
I think Nat gets it right here (and I second his recommendation of Antifragile:)
If you were in the wild, and you hadnāt eaten in four days, and you managed to kill a deer, you wouldnāt go forage for berries before eating it to āwork yourself up to it.ā Youād eat the damn deer.
Also, occasional shocks are good for your body, thatās the whole point of fasting in the first place. If you treat your body like glass then it will stay like glass. This is the same logic behind body building, hormesis, vaccinations, cold therapy, and any other process where we inflict small damages to increase the strength of the system (what Nassim Taleb calls āAntifragilityā)
When the time came, I wolfed down a pack of nuts with a total lack of table manners. It felt amazing.
Then my girlfriend got home from work and we went out for dinner. Unfortunately, we werenāt sure where to go and ended up in a crappy little bar/restaurant called Vitrine where I ate the most disgusting burger Iāve ever tasted.
This ārestaurantā was so bad it makes me angry. The food was barely edible, the wine was even worse, and donāt get me started on the service. Itās hard to think of a single positive thing to say about the whole experience beyond āthe food didnāt literally kill meā and āthe building wasnāt on fireā. The only thing I enjoyed was leaving. What an awful reintroduction to the world of eating.
So if you take one piece of advice from this post, let it be this: never go to the restaurant Vitrine on Rua Augusta in SĆ£o Paulo. Oh, and you might want to try water fasting too.