What I've learned from doing a 64 hour fast

Disclaimer: I'm not a medical professional, and this experiment is not backed up medically. I urge you to do your own research/speak to your medical professional to validate your ideas.

2 weeks ago I went on a hike with a good friend of mine, who does a lot of experimental challenges. He told me about his 3-day fast and I sparked my brain to give it a try as well.

You might wonder WHY someone would be interested to do such a long fast. There are a lot of good benefits from doing longer fast including:

  • Reduce insulin resistance
  • Fight inflammation
  • Improve cholesterol level and blood pressure
  • Aids weight loss
  • May aid in cancer prevention
  • Focus!

And that last one was an interesting one for me personally, the health benefits are very personal and hard to link back to the fast. But the focus you get during the fast is what made me interested.

I was told that from day two onwards your focus is sublime, and you're able to get more done!

Let's find out if that's true, but first a little bit about me:

You have to understand that I'm a big eater and all-around lover of food. (No wonder I'm going to marry a chef)

We had to plan the fast around my Fiancé working schedule, since she is a chef, she'll have to taste the food she makes.

So Sunday the 3rd of January became our starting point.

The last meal

Saturday, 7 PM we knew the fast was going to start soon. We decided to order a Pizza to get some high-carbs in and have a joyful last meal.

We finished eating the pizza at 8 PM, after this, we didn't have anything so the fast started.

I got very excited, my expectation would be that my stomach would be growling around 3 PM the next day.

For those who wonder what my normal day would look like:

  • Breakfast: Oats, whey protein, banana, water & black coffee
  • Lunch: Home-made generally low-gi bread, Avo, eggs
  • After-lunch: Cappuccino ☕️
  • Mid-day: snack; fruit, nuts, a protein bar (something like that)
  • Dinner: Home-cooked 6/7 days healthy, 1-day pizza/burger/etc
  • TV Time: Tea + 1 piece of chocolate 🍫

Seeing that I eat about 2500kcal a day on average. So in my mind for 3 days I'm going to live on 0kcal which sounded pretty scary to me.

We called it an early night, as usual, and went to bed at 10 PM

3 Day fast, Day 1

Day 1, 5 AM woke up by the sunlight, normal feeling as usual. At this stage, nothing was different than our normal routine.

Breakfast time, oh boy what a treat we got some water with a piece of lemon and a sprinkle of sea-salt...

For someone who loves food, this was disappointing.

We then decided to go on a hike, a really good idea if you are going to fast for 2 more days...

We packed our camel-packs (water backpacks) both hold 2ltr of water.

We spend about 2 hours hiking, nothing hectic and we ended up drinking the whole 2 liters each.

Still feeling good, nothing weird to me, just feeling thirsty, probably because of the hike.

Lunchtime 🤤

We had some water with electrolytes which made sure we stayed hydrated.

Electrolytes are powders you can add to water, to get your nutrition in with zero kcal

After lunch, we decided to go for a 90-minute Thai massage, which was helpful to pass some time and relax a bit.

After this we ended up doing some personal stuff for ourselves. I worked on the blog for a bit, and my fiancé did some reading.

The dinner on day 1, bone-broth, this is water that you boil bones in for 12+ hours and freeze to extract the fat. It doesn't have the nicest taste to it, but it's not bad at all.

This is what bone broth looks like

We then decided to watch a movie, and have some plain green tea.

At around 9 PM we were both exhausted and went to bed. This was a bit unusual for us, feeling so tired.

3 Day fast, Day 2

We woke up at 7 AM, so this was a long, deep sleep. It feels good to sleep so well. The motivation was 110% and no hunger feeling.

Breakfast today was a cup of black coffee, which was very welcoming. Mainly because you miss the taste of anything.

In the morning I did my blogging, and I felt so motivated. I started live-streaming which was cool and it helped pass time.

At 9 AM, I started my day job, it was a busy day, with the launch of a project which ended up taking up my lunch-time.

Of course, we didn't really need lunch so it was ok.

During the day, we made sure to drink enough water, some of the waters contained a sparkle of sea-salt.

The sea-salt helps prevent you from becoming dizzy

After work, I decided to finish the live-stream so I did about 1 hour of streaming to finish the article.

After this, we went ahead and did our workout, definitely felt a bit weaker. It's hard to explain this I felt like I was a sloth, very slow in movement.

I had to move slow during our HIIT workout because I felt like I would faint if I went too fast.

After the workout, I felt great again, drank some electrolyte water, and had a shower.

If you're wondering if I wasn't hungry, No! Not at all, the hunger never came to me. (I think it has to do with the high water intake)

Dinner for today: Another cup of bone broth! Today was tastier than yesterday which was a win.

We had another tea before bedtime and went to bed at 10 PM (Normal for us)

I had some issues falling asleep, spend about 2 hours on the iPad checking Twitter and reading some articles.

3 Day fast, Day 3

I woke up, really groggy, due to the bad sleep my Fiancé was struggling this morning. She had some issues feeling super dizzy and hungry.

I told her to break the fast and make a smoothie. She asked if I would also stop, but I decided to go on a little bit longer. (She felt way better after the smoothie and is doing well).

I was still not feeling hungry, could even watch her drink the smoothie.

Important: Don't break your fast with heavy foods!

Started with the live-stream again, and the working day after that.

At lunch-time, I was feeling quite dizzy and just a bit off. (My mind felt slow)

I could develop like normal, but responding to question took longer than I was used to.

Instead of lunch, we decided to go to the appliance store. We are looking for a new fridge, which we found and bought.

By the time we came back, it was about 1 PM and I was getting hungry by now.

I decided to break the fast, with a bun with some avocado and boiled eggs.

The burger that broke the fast

I would have been better off cutting the bun, this was a bit too much fiber.

You might think, why not break with heavy foods? and that's a valid question, your stomach is pretty empty by now, and anything you put in it will have an effect, which may be upsetting it. Read more about that here.

It was done, the fast lasted for 64 hours and I was still alive.

What I've learned from a 64 hour fast

It was an interesting journey, this whole fast. And not a bad experience at all!

I expected to be hungry all the time, which didn't happen until day 3, noon.

I weighed myself after this fast, and it turned out I lost 3,8 kilos in 3 days (highly due to water, I would think)

You can't poop anymore, which is such a weird feeling, I ended up being able to poop on the third day, and it was weird! It wasn't your normal poop and smelled bad, so be prepared if this happens to you. (Not everyone has this experience)

To come back to the original point:

Focus, for me that was personally way better! I normally spend about 10+ hours a day behind the computer and feel empty. During this fast, I upped this to 14+ hours a day introducing the live streaming, and I was less tired than normal! So for me, it was a big yes.

If you also need to be super focussed for a short period, give it a try and let me know your findings.

Pros of doing a 3 day fast:

  • Day 1 sleep is amazingly good
  • You drink more water
  • You have way more concentration at least on the first 2 days
  • Good way to reset your body
  • Lose some weight
  • Save money on food

Other than that, it does have some potential health benefits that studies have shown:

  • May promote autophagy (the process of breaking down old cells and recycling them)
  • May help lower blood pressure
  • May help improve insulin sensitivity
  • May lower the risk of several chronic diseases (diabetes, cancer, and heart diseases)

Negatives of doing a 3 day fast:

  • You'll miss the taste of food
  • You might feel dizzy and dehydrated (try and keep up the water intake + sea-salt)
  • You might lose the wrong type of weight (muscle)
  • You need to pee a lot!
  • You can't go for poops daily

A week later

Reflecting after a week, I still lost about 2kg's, I eat way less. Which means I just don't have the space to store more food.

We both drink way more water on a day and feel completely back to normal in our fitness levels.

What's next?

You might be wondering, are you going to do this again? The answer to that is Yes, we plan to introduce a 24 hour fast every week. (Dinner -> Dinner).

And possibly every quarter a multi-day fast.

It was super doable, didn't have any negative effects, overall way more productive so 5 stars from us!

If you plan to do a fast yourself and have some questions about it, feel free to send me a message!

Thank you for reading, and let's connect!

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Comments (4)

Edidiong Asikpo's photo

I respect you Chris Bongers!

I honestly don't think I can stay without eating for a day, not to talk of two or three days.

I am also curious to know how not eating helps you focus. Please explain.

Show +1 replies
Edidiong Asikpo's photo

But it worked out well, you don't really miss it weird enough.

Wow, for real?

As for the focus, this is the scientific reason: Fasting increases levels of brain-derived neurotrophic factor (BDNF), a protein that interacts with neurons in the hippocampus, cortex, and basal forebrain (the parts of the brain that regulate memory, learning, and higher cognitive function — uniquely human stuff)

This makes a lot of sense, Chris. Thanks for explaining!

Chris Bongers's photo

Edidiong Asikpo For the first part: At least for me 100%

My Fiancé struggled on day three in the morning, so it might be slightly personal.

I do think being super busy helps with not thinking about food