My 5 days Prolonged Fasting Experience

I recently did a 5 (working) days prolonged fasting successfully without any food at all (only liquid) and experienced one of the most productive weeks ever. I wanted to share my experience here and some context of intermittent fasting for starters, if helpful.

Obviously, I’m a Product Manager at a fintech startup and not a doctor, so none of these information should be taken as health advice. Please consult with your doctor for medical advice.

I’m using a fasting app called Zero

In this fasting period, I managed to do and complete these numerous complex and context switching stuffs, which are very remarkable to me:

  • Review countless asks/contents and made low to high risks decisions
  • Grooming, sprint planning and retrospective ceremonies
  • Lots of design thinking
  • Revamp our documentation https://docs.xendit.co/webhook (really not easy)
  • Unblock multiple teams
  • any many more

Fasting allows me to focus better. It’s actually quite counterintuitive to what most people believed that we can’t function well when we are hungry. I can say it was one of my most productive week easily looking at my completion rate of my Notion To-Dos list.

Besides being productive professionally, my body also run more efficiently from this prolonged fast. These are few of the things I feel during fasting:

  • Appetite decreases significantly (not sure if I should be happy or sad as a food lover)
  • Sex hormone decreases
  • Lose 5kg (pls don’t get excited about this because my body mainly burn more liquid than fat when fasting)
  • Brain concentrates and focus better (vs. getting sleepy after meal)
  • Emotionally more stable and patient towards others
  • Face feels cleaner and shinier (and no I don’t use any skincare)

Quite an experience and tremendous benefits for me so far. The tradeoffs? I felt very hungry on the 4th night, but other than that, feels like normal day! (and I didn’t have any heartburn this time oh yeah 🎉)

All of these benefits are great, but how was the journey to get here? Is it painful? Well, let’s find out!

The journey to get here is neither easy nor instant. When I first learned about intermittent fasting, I started from skipping breakfast first, then skip my lunch and only eat once a day. All of these definitely are not instant and took weeks or even months to adapt, feel comfortable, and form a habit.

I did my first 72h prolonged fasting 10 months ago. It was a hell of experience 😂 with all the heartburns. I haven’t done any prolonged fasting until just recently. This time, with 113h fast, thankfully no heartburns at all and this is the mainly the reason I can last for 5 days.

I used water, salt water, and green tea to help me went through the fasting days; salt water for electrolytes and green tea to decrease my appetite. I don’t drink coffee, but if you enjoy coffee, I heard you can also drink coffee for fasting but without sugar and milk.

I kept myself busy and focusing on work to ignore my hunger. I normally only crave foods when my brain is not doing anything, so keeping my brain focus is key to my fasting success.

Sleeping might be tricky as I personally am not comfortable going to sleep with an empty stomach and feels the growling (lol 😂), but I just filled in the stomach by drinking lots of water before I sleep and the hunger went away.

I, however, didn’t do any physical exercise during prolonged fasting as I’m being conservative to reserve energy.

Yes, but probably not frequent. Maybe a 72h fast every 2–3 months to let the body recycle periodically.

If you’re new to this fasting concept, you’re probably wondering: why should I fast and suffer more? Aren’t my daily struggles enough to make me suffer? Am I not suffering enough? You are definitely not wrong at all haha 😂. Fasting is definitely not for everyone, but there are benefits and also side-effects of fasting.

Fasting gives you anti-aging, lower your cancer risk, and many more. When we are doing fasting, our body run through multiple stages to enter survival mode and run the body more efficiently. All of these information are from Fasting App (great app btw!)

  1. Ketosis (12h-24h): The body can finally tap into fat storage and use fat to fuel the body instead of glucose. Ketosis produces fewer inflammatory by-products, so it provides health benefits to your heart, metabolism, and brain
  2. Autophagy (24h-48h): At this point, your body triggers autophagy (literally means “self-devouring”). Cells starts to clean up their house. They remove unnecessary or dysfunctional components.
    During autophagy, cells break down viruses, bacteria, and damaged components. The main benefit of autophagy is best known as the body turning the clock back and creating younger cells
  3. Growth Hormone goes up (48h-56h): Growth hormone increase your lean muscle mass and improve your cardiovascular health
  4. Sensitive to Insulin (56h-72h): Decrease risk of developing diabetes. Lowering insulin levels has a range of health benefits both short term and long term, such as activating autophagy and reducing inflammation
  5. Immune Cells Regenerate (72h): The body regenerates new immune cells at a rapid pace to fill in the “guardian vacancy” as these guardian aka damaged immune cells have been devoured from autophagy stage. Immune system becomes stronger and stronger

Despite all of the great benefits above, fasting has side effects you must consider, such as heartburn, tired, cold, headaches, or even fatigue and fainting. Most of them may occurred when your body is trying to adapt to fasting. If you feel uncomfortable, you should immediately stop and consult your doctor

Last thing I want to point out for starters, having the right mindset is very important for a successful fasting. To keep things simple, my fasting mindset is

During ancient time, our ancestors must hunt foods in the forest and not eating anything for days, yet the human civilization survived until now. I must have inherited this ancient mechanism of survival and don’t need to eat 3 times a day

I’m a huge food lover, but when I’m doing fast, I’ll switch to this fasting mindset. You can also use other motivations, like health, social, or monetary benefits, to build the right mindset.

These are some knowledge and insights for those who haven’t been exposed to fasting’s information or didn’t know where to find the information. Always wise to do your own research on top of these!

Okay, that’s all! Before I let you go, I must say I’m not a fasting advocate or cult here, so I’m not interested to influence you to do fasting. You do you! And as I mentioned earlier, these information are based on personal experience and my research and shouldn’t be interpreted as medical advice.

If you’re doing fasting, I’m curious to hear your story, do share your experience in the comment section below! 😀 If you’re an expert and found any misinformation here, kindly point out the errors alongside the correction 🙇

Thanks for tuning in and read my prolonged fasting experience. Hope there’s something you can take away with you! Bye and stay healthy folks!

Product Manager at Xendit. Alumni of ITB Informatics Engineering. Building payments infrastructure for SEA. Common sense, empathy, compassion, and mindfulness