I didn't eat food for 3 days, here's what happened

An experiment in doing nothing and consuming nothing except water, salt and sunlight for 3 days.

I didn't eat food for 3 days, here's what happened

My friend Michael messaged me asking if I was interested in doing an extended fast.

I'm due, he said.

Sure, I said.

Four days?

Three days for me, I've got a Brazilian Jiu Jitsu competition coming up I'm training for.

Sounds good to me.

Last year I did 5 days, the year before that, 4 days. This article completes the trifecta.

Disclaimer: I'm not a doctor. I write articles about and make videos of things I do. Although this documents what happened to me during 3 day water-only fast, you shouldn't take it as medical advice. You're smart enough to take your health in your own hands.

Short version

I'm not going to rattle off all of the benefits of fasting (weight loss, gut healing, feeling in-tune with nature, tapping out of the normal way of doing things etc).

You can read those elsewhere.

So here's what, why, how.

  • What I did: A 3 day (dinner to dinner 3 days later) water-only fast, no coffee, no tea, no food, water and salt only.
  • Why: Fun. The only reason I do anything. Plus, a group of friends were doing it so I joined in. We had a group chat going and it was fun to share experiences.
  • How: Have dinner on day zero (a smaller meal), go for a long walk the next morning (to speed up your body entering ketosis), chill out when it's supposed to be mealtime, relax, drink plenty of water, pinches of salt in water and magnesium tablets here and there to prevent cramping. Realise how much you value food and meal time with others. Break the fast 72 hours later.

Let's get into the longer version. I'll do rapid fire question style to begin then a day by day journal to finish.

Video documentary

There's a video version of this article available on YouTube.

What is a 3 day fast? What happens?

For me, a 3 day fast means no food at all. Water only. No coffee, no tea, no anything.

Water and salt is okay because (for scientific reasons unknown) you do start to get muscle cramps the further you go on. So the salt helps prevent the cramps.

My guess is because you're not eating food, you're not getting electrolytes and because most water from taps is filtered, you're missing the natural minerals you'd find in water.

Let me add sparkling water if you're feeling fancy. I was feeling fancy.

What was the hardest part of the fast?

Contrary to what you might think, hunger wasn't the hardest part. After 12, 16, 18 or so hours, your body begins to realise the state you're in and it starts to help you.

Throughout the whole 3 days, I never really felt hungry.

In my past fasts, I've found once I'm into nutritional ketosis or fasting ketosis, where the body starts to use fats (ketones) for fuel rather than carbohydrates (glucose) and are blood ketone levels are 0.5 to 3.0 millimoles per litre (mmol/L) things become smooth sailing.

For me, the hardest part wasn't a lack of food more so a lack of the activities you'd do around food.

My favourite activity in life is to eat food with people I love. I look forward to eating dinner with my family every day. So missing out on that for any given period of time is always a challenge.

Fasting gives you a refreshed respect for family mealtime.

What was the best part of the fast?

Being in tune with nature. I can't describe it. But by 36 hours or so in, I began to relax , I feel like my body may have started releasing hormones to make me feel high, a way of dealing with the situation. Maybe your body eating itself (autophagy) is a form of psychedelic.

Since I had plenty of spare time due to not eating, I went for long walks each day. During the afternoon walk of the second day, my senses were turned up, waves sounded crisper, bird songs filled my ears, greens got greener, the salt air tickled my nose.

And of course, the anticipation of food.

Often in life I've found the anticipation of event to almost if not as good as the actual event itself. So from the time I stopped eating to the time I broke the fast I was looking forward to eating once again with family and friends.

What was your last meal before the fast?

Steak, onions and a glass of milk. I'd read online you generally want to have a low carbohydrate meal, or even spend a few days prior eating a low carbohydrate diet before kicking off a fast.

steak and onions on a plate with a glass of milk to the upper right
My last meal before the 3 day fast. Steak, onions and a glass of milk. Lower on carbohydrates to help with entering ketosis over the next couple of days.


To speed up the transition of your body into fasting/nutritional ketosis.

Generally the body uses glucose (carbohydrates) as fuel. But when it's deprived of glucose, say during a fast or during a period of eating low carbohydrates, the body will start to switch to using ketones (fat) as fuel.

The body tolerates being in either state, glucose burning or ketone burning. However, it's often the transition between either state that becomes difficult.

For example, the reason why you might get a headache after not eating for several hours is because your body is deprived of the fuel source its used to (glucose or carbohydrates) and is now trying to switch over to another fuel source.

In my experience with extended fasts, accelerating this switch over (from carbohydrate burning to fat burning) is favourable.

For me, it's usually a few hours or so at the end of Day 1 where the fuel source switch makes itself known through lethargy and a shorter than usual temper.

What was your first meal after the fast?

In an ideal world I would've broken the fast with a meal similar to what I started it with (or the last meal I ate before I started the 3 day fast). Simple. Steak and salt or steak and salt and onions.

However, since we were fasting as a group, it was easier to book a restaurant at a central location than get everyone to go to someone's place.

We went to a rib joint. Rolling in I could smell the place from a block away. Smoke billowing out of the roof. Even before getting there I'd pored over the menu deciding what to get. It's all about the anticipation.

I ordered ribs. Standard sauce, not spicy. And a side of coleslaw. Not too big not too small. There were fries and other options but I tend to avoid anything fried. Though, I did end up digging into someone's leftover sweet potato chips after I'd finished the ribs and realised my gut was okay.

pork ribs with sauce and coleslaw on a rectangular plate from Big Roddy's
The meal I broke my 3 day fast with. Slow-cooked pork ribs and BBQ sauce with a side of coleslaw. Some say to take things easy on the first meal and eat something simple (simple meaning whatever you make of it). However, I've never really noticed an issue with breaking a fast so I went for "the best ribs in Brisbane".

Some people say go easy on the fast breaker meal. And what simple means can be up to you. A singular food maybe. Rice cakes on their own. Blueberries, other fruits. The thought here is because your stomach and gut haven't been working over the past couple of days, they might be more susceptible to irritation. However, I've never really had any gut issues or troubles breaking a fast so I went for the not-so-simple combo of ribs and coleslaw.

What were your blood ketone measurements throughout the fast?

Beside the zen like feelings I get when my body enters a state of fasted ketosis, I used a blood ketone meter to be little more precise.

For context, the start and end times are below.

  • Fast start: 7 July 2021 7:30pm +/- 30 minutes
  • Fast end: 10 July 2021 7:30pm +/- 30 minutes
  • Day 0 (day before starting the fast): 7 July 2021
  • Day 1: 8 July 2021
  • Day 2: 9 July 2021
  • Day 3: 10 July 2021
  • Day 4 (day after breaking the fast): 11 July 2021
Time Measurement (mmol/L)
Day 1, 9:21 AM Low (nothing registered)
Day 1, 12:29 PM 0.3
Day 1, 5:11 PM 0.7
Day 1, 10:06 PM 0.9
Day 2, 10:29 AM 2.4
Day 2, 5:10 PM 2.4
Day 3, 9:44 AM 2.8
Day 3, 5:13 PM 3.0
Day 4, 8:39 AM (after breaking fast) 0.9

What was your sleep like?

During a previous fast, I suffered from poor sleep. However, I'm starting to think that was because I consumed caffeine (black coffee) throughout.

For the 3 day fast, I had no caffeine at all, no coffee, no tea. And before bed each night I took a magnesium tablet, magnesium has been shown to help with sleep, plus, it feels like it works.

So this time round I noticed no real issues to my sleep except for waking up quite dehydrated which made getting out of bed harder than usual. Though, this fixed itself an hour or so after waking after consuming a few glasses of salt in water.

What was going to the toilet like without eating anything?

Number 1: darker in the mornings due to dehydration overnight but returns to normal throughout the day with normal water (and salt) intake.

Number 2: uneventful.

chart of different urine colours showing from 1 (hydrated) to 8, a darker colour (very dehydrated), my urine during the 3 day fast in the mornings was somewhere between 6 and 7
After waking up on day 2 and day 3, I was a bit groggy. But after going to the toilet, I realised it was probably because of dehydration. My urine colour was somewhere beween 6 and 7 on the chart above. The feeling of grogginess and tiredness subsided after an hour or so and 2-3 glasses of salt in water.

Why do a 3-day fast?

Fun. As I said before, that's my main reason for doing anything. But otherwise, there are a plethora of reasons.

I'm not a doctor nor a practicing gut health specialist. So I can't offer clinical reasons, only reasons that I've experienced.

Food reset

During an extended fast, my relationship with food gets reset. I miss eating with family and friends. And I realise how much the activity means to me. I've made it a point never to eat with technology, when I eat I eat, nothing else and to spend as little time eating alone as possible.

Less fluff

At the end of a fast, I notice, although subtle my body is less puffy. My jawline is more pronounced, my abdominals are more defined. I don't know what this is. It could be less water, it could be less inflammation, it could be that carbohydrates make my cells swell and entering ketosis takes care of that swelling.

Shaking up routine

The final reason for me. Doing something you would've thought insane a few years ago. After multiple extended fasts, I'm used to it now. But if you'd told me a couple of years ago I'd spend 3 days without food and only consuming water and salt, I'd have told you to get f***ed. If I can go without something as fundamental as food for multiple days and still function, what else can I do?

Other valid reasons you might consider:

  • Taking your health into your own hands – This is the biggest one. There's a lot of information out there on how to improve your health. Most of it is BS. But you'll never know until you try it yourself.
  • Weight loss – I definitely lost weight during the fast, however, most of this is water weight. I've since gained in back (I'm writing this article a couple of weeks after). Let's face it, you're not going to make dramatic long-term changes in 3 days. Better to develop the habits of moving every day and being thoughtful about what you eat than randomly go through 3 day extended fasts.
  • Gut health – You might be surprised that the human body is pretty good at repairing itself. If you've got a gut issue, perhaps giving your gut a break from food all together and letting it do its thing for a couple of days can lead to benefits. Again, I'm not a doctor. However, in my experience, if I've got a slight gut issue (rare), not eating for a while helps. Many wild animals instinctively stop eating when they become sick.
  • Rebel – Fasting from food, from anything you'd usually consume day to day is perhaps the ultimate rebellious act against the general consensus of improving a health situation by adding more (medications, treatments, etc). Fasting is a way of avoiding iatrogenesis (an issue introduced by a treatment which had the intention of fixing things), improval via removal.

How do you do a 3 day fast? How much weight did you lose?

Actually doing a 3 day water-only fast is quite simple. You don't eat food for 3 days and only consume water, salts and electrolytes.

Some will claim teas and caffeine and black coffee is okay. But for me, if I'm going to do something, I go all the way.

For specifics, I'll let my journal entries talk for themselves below.

But before that, let's talk about weight.

How much weight did you lose during the fast?

By now you know I didn't do the fast for weight loss. Again, 3 days isn't enough time to make lasting changes. For weight loss, habits work better than extreme events.

And since completing the fast, I've gained it all back. I'm near (or even heavier since I've been lifting weights due to the Brazilian Jiu Jitsu gym being closed for COVID) to where I was I started.

If you've gained it all back, why put the weight numbers here then?

Because weight is one of the easiest things to measure. I can't measure and tell you how I feel inside but I can step on a scale and show you what it says.

I weighed in naked each morning after waking and after visiting to the toilet.

Day Weight Change (from previous weight)
0 77.1kg (170.0lbs) -
1 76.4kg (168.4lbs) -0.7kg (1.54lbs)
2 75.2kg (165.8lbs) -1.2kg (2.65lbs)
3 74.4kg (164.0bs) -0.8kg (1.8lbs)
4 74.8kg (164.9lbs) +0.4kg (0.9lbs)
30 (1 month after fast) 77.8kg (171.5lbs) +3.0kg (6.6lbs)

As you can see, one month after finishing the 3 day fast, I've since gained the weight I lost back, plus a little bit more. However, this is consistent with what I've been doing, eating slightly more than usual and lifting weights regularly. It's Winter here. Bulking season.

How did you feel during the 3 day fast?

Feelings are best recorded in the moment. So instead of trying to remember, I'm going to copy the journal entries I created each day verbatim.

Day 1, July 8, 2021

  • 8:30 AM weighed in at 76.4kg, 13 hours in
  • 9:23 AM going for walk, blood ketones low (no measurement)
  • 11:59 AM went for 2 hour 15 minute walk to burn extra glycogen stores and push my body into ketosis, 12000ish steps, chilling, 16 hours in, feeling fine, very zen’d out, no rush, just being, drinking usually makes me want to do something, today I’m happy just resting, going to drink some salt water and measure ketones soon
12000+ and 2 hour+ walk on the first day of the fast to burn up excess glycogen stores and kick start my body into ketosis
Going for a 2+ hour walk on the first day of the fast to burn off extra glyocgen stores and help my body enter ketosis. You could do the same with high intenisty interval training. I took along plenty of water and sipped it along the way.
  • 5:16 PM 0.7 mmol blood ketone measurement, chilled out day, did some admin work in the afternoon, starting to feel a little cold, is this from lower thyroid activity? Found a video by Thomas DeLauer on why you feel cold during a fast (it could be one fat changing to another and burning itself instead of generating heat)
  • 8:18 PM went to BJJ training, training at about 50%, no hunger, thinking of food though, the hard part is missing dinner with the family, possibly my top favourite activity in the world, plenty of salt and water before bed, little bit foggy but nothing too outlandish

Day 2, July 9, 2021

  • 9:48 AM woke up 830ish, 75.2kg, feeling a bit busted, definitely dehydrated, piss a dark colour, no trips to the bathroom yet, over halfway, relaxed but no hunger, raining so it’s chill, no walk, sipping salt and water
  • 10:35 AM checked blood ketones, 2.4 mmol/L, into nutritional ketosis, dancing helps, hydration coming back thanks to plentyyyy of water (4 larger glasses)
  • 11:13 AM been puttering around all morning, going to do a little bit of work, nothing too major just completing some things from before, had a longggggg hot shower, that gave me energy and took away some of the cold feeling
  • 12:29 PM done some computer work, not much, bouncing between things, drinking more water has helped, energy is humming along nicely, no real ups and downs you typically get with caffeine, going to chill out for a while then do some reading/clean closet
  • 3:22 PM cleaned upstairs closet, chilled out around the place, went on an afternoon walk, sitting in nature feeling very tuned in, no feelings of hunger, very peaceful and very at rest, however I feel like if I had to do something strenuous, the energy would take a little while than usual to build up, the warm up would take longer, though I did some work earlier and concentration was there, senses are all turned up
  • 5:14 PM afternoon walk, chilled out, not feeling hungry, feeling connected to nature, sense of smell has turned up, I can smell everything, I thought how could I take advantage of this and bought a scented candle to enjoy, reading the Lindy newsletter in the evening, On Diet (part 1), specifically the parts on fasting — is the peacefulness the lack of caffeine or the lack of food? Or the more time in the day since not having food?
  • 9:12 PM went to BJJ training, had a lot more energy this evening, deep into ketosis, sense have gone weapons hot, my sense of smell is next level, there’s a pizza shop outside jiu jitsu and let’s just say my nose was like a dog on heat

Day 3, July 10, 2021

  • 9:58 AM woke up about 830, sleep was pretty good through the night, supplemented a magnesium tablet before bed along with a bit of salt in water. Hydration is really key during fasting. Woke up a few times through the night, a little restless here and there, woke up to garbage truck at 6am-ish and again probably around 2am, weighed in at 74.4kg, blood ketones are 2.8mmol/L
  • 11:05 AM sat reading in the sun for an hour or so, stumbled upon a chapter in Hemingway’s A Moveable FeastHunger was good discipline, no hunger now, feeling very relaxed, a little cold when out of the sun
  • 4:17 PM finished reading in the sun and then went and had a long hot shower to warm up, that’s what you notice when you’re fasting, how nature effects you, it’s windy today so anywhere outside of the sun I felt a slight chill
  • Went for a long afternoon walk, 7km’s or so, just over an hour
  • Chilled out during the afternoon did some research trying to find arguments against fasting, lots of for but what’s against? The main one seems to be stress — what defines good and bad stress? Lack of energy? Or enough to exist and chill?
  • Was talking to a friend on the phone before, she told me about the cookies she made… dangerous conversation to be having during an extended fast
  • 9:27 PM broke the fast with the crew, at all feeling prime, ready for bed, breakfast with family tomorrow, very excited

Aside from daily journal entries, I also compiled a bunch of recurring thoughts before breaking the fast.

Journal entry from end of fast

During the fast (and most days) I write in my journal. A conversation with myself which sometimes leads somewhere sometimes doesn't.

The below passage is from an hour or so before breaking the fast. Collected (unedited and unfiltered) thoughts of what was going on.

Last couple of hours until the 3 day fast ends

What a way to finish it off other than some writing. I write every day for a reason. To collect my thoughts. To debunk things to evaluate things to explore things and most of all because it’s fun.

That’s the main reason I do anything, fun.

I’ve got the nice smelling candle going again. If my senses of smell are turned up, why not buy a candle and reap the benefits of it?

I wanted to spend the afternoon investigating different arguments against fasting. But I wasn’t really about to find any. Other than the article from Harvard which was a little bit of the standard play:

  • Intermittent fasting may maybe you feel sick
  • It may cause you to overeat
  • Intermittent fasting may cause older adults to lose too much weight
  • It may be dangerous if you’re taking certain medications

These things made sense, then I thought about my own detractors of fasting.

The main for me is stress. That’s what it’s all about right. If a body part gets stressed, it gets inflamed, perhaps that’s what excess fat is, it’s the body is inflamed on a whole level and in turn the fat comes to try and insulate it.

Some questions I wanted to explore was whether or not fasting increased metabolic stress? But it seems briefly fasting can increase the metabolism. But after a longer period of time it may cause the metabolism to slow down.

And as for the good and bad stress, what defines good and bad? What is stress to begin with?

If you classify stress as the lack of energy, perhaps that’s what I’ve been experiencing. I haven’t been really wanting to get involved in any heavy duty tasks and have instead been chilling for the past 3 days, reading, writing, walking.

I’d say most of the stress for me (what method do I have of measuring the stress?) comes from the things you’re not doing. As in, I’m not able to do one of my favourite activities in the world and that’s eat food with friends and family. But does it make me value the art of breaking bread with loved ones even more?

A pro: Fasting is a way of becoming proactive about a health situation. It’s like the ultimate rebellious act from many health promoters. You’re saying I’m just going to take a break from everything (including something as fundamental as food) for a little while and relax. See you on the other side.

Why fast? Why not fast?

  • Stress — What is stress? Where does it come from? I’m not hungry…. But I want food, I enjoy spending time with family and friends and eating, what’s good stress and what’s bad stress? Is a little bit of stress every so often a good thing, e.g., abstaining from food to revalue it or improve a health situation
  • Becoming proactive about a health situation – taking your health into your own hands
  • Low energy – over the past few days I haven't really felt like doing much except chilling out, though this isn't necessary a bad thing
  • Iatrogenics — fasting is one form of avoiding iatrogenics (a harmful effect caused by a medical treatment), if you’ve got some kind of gut issue going on, potentially fasting is a way to remove it, improval via removal
  • Breaking a fast feels the opposite of a hangover
  • You always want what you can’t have…

That’s it. That’s it I think. A good way to wrap things up before heading to dinner. It’s going to be a fun meal time. I’m excited for dinner. Excited for the food that’s going to be delivered to my place tonight to.

I felt the most in tune with nature yesterday afternoon. Today I feel the wind has thrown me off a little bit. I’m still in a zen like state but I’m ready to be done, potentially since I know the end is close. If I had set myself out on a 4 or 5 day journey and known the end was further away, perhaps I’d have a different outlook on things.

When will I do the next one? Every 6 months or so seems like a good idea. Potentially not a 3 day one either. I could experiment with smaller, 36 hour and 48 hour maybe. I think the 3 days plus takes it out of you. It throws off your life a little too much. Maybe, maybe not.

What would’ve I have liked to have done these 3 days?

Hmm. That’s another point to add. You miss the things you’re not doing. As in, you feel like you should be doing something but you’re not you’re just chilling around. Which isn’t a bad thing either. Relaxing and doing nothing is a part of life as much as doing something is a part of life.

I’m going to wear something nice to the restaurant. I’ll make a little clip before going in and then another clip after breaking the fast.

What are the points I’d like to talk about?

I’ve got a few but I can’t talk at length at them because I don’t know them. I can only speak from first hand experience.

Today has been a big and relaxing day on tour:

  • reading
  • walking
  • writing
  • ready to finish
  • excited
  • sipping plenty of salt in water
  • having a magnesium tablet here and there

Time to record a clip and then start getting ready for dinner.

Progress photos

Every morning after weighing in (and after breaking the fast) and saying a little jingle on camera for the video documentary I took a progress shot.

As you can see, they're all in different lighting and all slightly different angles. I tried to keep things as consistent as possible, even with the cropping, they're all different sizes but I tried to line the shoulders up.

Again, no meaningful changes are really going to happen in 3 days, most of the weight I lost was likely water weight. The progress photos are more so just an easy to measure thing during the fast. And cool to look at. I look at my face quite often and to me, my face and jawline on day 4 is less puffy than day 1.

progress shots from day 1 through to day 4 of the 3 day fast
Unedited mirror shots from day 1 to day 4 (after the fast). I tried to keep things consistent, shooting at the same time and same place but you can clearly see different lighting effects (there's a window to the left). For me, the biggest change comes with the jawline between day 1 and day 4. Day 4 is more pronounced.

Resources to learn more

While fasting I like to read and learn about fasting.

Here are some resources I found valuable.

  • The Lindy Newsletter, On Diet (Part 1) – The Lindy Newsletter explores the Lindy effect (things which have been around for a while tend to stay around for a while). On Diet (Part 1) explores fasting through the eyes of tradition. Almost all religions have some component of fasting involved.
  • Why you my might feel cold during a fast video by Thomas DeLauer – When fasting for extended periods of time (16-18 hours+), I usually get a deep cold chill. I wondered why. Turns out there could be multiple reasons. This video helped to explain a few.
  • Zero fasting app – You don't need an app to help you fast. But Zero makes it fun. I enjoyed watching the pretty counter tick down. It also offers educational material for what happens to your body during fasting.

And if you enjoyed this article, check out my other extended fast articles and videos, they're created in a similar style.