– “Do you want to join our 65-hour fast?”
That was the text I received four days ago.
A good friend invited me to join a group of 18 people across the globe fasting in solidarity with her husband, who is undergoing chemotherapy. He has become – somewhat reluctantly – a pro in fasting, using it carefully before treatment to help reduce post-chemotherapy sickness. What began as an act of support became one of the most educational, confronting and transformative experiences I’ve had with my body.
We were guided through every stage, reminded constantly that ‘we could stop at any time’, and encouraged to listen deeply to our bodies. I completed the fast this morning – 65 hours after my last meal – and I’m still absorbing just how much I learned.
This is not a post about willpower.
It’s about biology, awareness, rest – and changing how we relate to food.
The Starting Point: 0 – 12 Hours
Last meal: 2pm – My final meal was simple and nourishing:
eggs, spinach, and a small amount of meat.
This matters. How you ‘start’ a fast influences how you experience it.
In the first 12 hours, the body is still digesting and using glucose from your last meal. Insulin levels begin to fall, and your body starts to switch from “fed mode” to “fasted mode”.
That first night, I slept surprisingly well – although I dreamt vividly of pancakes drenched in maple syrup. Bitter-sweet, but oddly reassuring.
12 – 24 Hours: Glycogen Depletion
The first day without food
I woke feeling okay and genuinely looking forward to my black coffee (allowed – along with a couple of cups of black tea or coffee per day). Then came water. Lots of it. Plus sugar-free electrolytes.
By this stage, the body is ‘burning through stored glycogen’ (glucose stored in the liver and muscles). Once this runs low, the body starts preparing for its next fuel source: fat.
What surprised me most wasn’t hunger – it was awareness.
I became acutely conscious of how often I think about food. How much I snack. How rarely I eat proper meals, instead grazing on “small healthy things” throughout the day. It made me question:
* How much of my eating is habit, not hunger?
* How many “healthy” snacks are actually ultra-processed?
* How often do I read labels properly?
So many foods marketed as ‘good for you’ are anything but – damaging gut health, confusing our cells, and keeping us locked into constant insulin spikes.
This first day was easier than expected (all bar having to cook spaghetti bolognese for my family) and mentally illuminating.
24 – 36 Hours: Entering Ketosis
Night two. This is where things shifted.
With glycogen depleted, the body transitions into ‘ketosis’, burning fat for fuel and producing ketones to power the brain. This is metabolically demanding and it shows up differently for everyone.
That second night, I slept terribly.
I had vivid nightmares and woke cranky, restless and foggy. This phase can feel uncomfortable because the body is ‘learning to run on a different fuel source’. Hormones fluctuate, cortisol can rise and sleep can suffer temporarily.
36 – 65 Hours: The Hardest Part
Day two. This was the toughest stretch.
I felt weak, irritable and – a first for me – jealous of my cats as they gobbled their breakfast.
At around 4pm, I was convinced I was going to quit. (not because of the cats – I have low blood pressure and anaemia, so I needed to be especially cautious) I felt faint and overwhelmed.
The group reminded me:
Rest. Rest. Rest. No pushing. No heroics.
I lay down. I practised Coherent Breathwork, which helped enormously in calming my nervous system. I watched three episodes of ‘The Traitors’ – doing my best to ignore the endless castle breakfasts and lamb shank dinners – and let distraction do its thing.
By resting, rather than fighting, I gave my body space to adapt.
48–62 Hours: Autophagy
‘Cellular clean-up mode’
This was the stage that fascinated me most.
After around 48 hours, the body significantly increases ‘autophagy’ – a process where cells break down and recycle damaged components. Think of it as internal housekeeping.
Old, dysfunctional cells are cleared out. Inflammation reduces. Cellular efficiency improves.
This is one reason fasting is being studied so closely in relation to cancer treatment, longevity, immune health, and metabolic repair.
That night, I slept much better.
I woke early with one thought:
‘YES, I CAN EAT.’
Almost.
The Refeed: Just as Important as the Fast
Ending a fast properly is crucial.
The digestive system needs to be gently woken up. Rushing this can cause discomfort or undo benefits.
Breakfast was ‘chicken bone broth’. Despite fantasising about it for half the previous day, it felt like seeing someone you don’t really like at the finish line of a marathon.
Later, very slowly, I ate:
Refeed Meal One:
- One avocado
- Pea shoots
- Kimchi
Refeed Meal Two:
- Kefir yoghurt, small portion of nuts
Mindful. Chewed. Unrushed.
Over the next few days, what I eat matters deeply. Whole foods. Gentle digestion. No shock to the system.
What I’ve Learned So Far
This fast gave me far more than I expected.
Physically:
* Clearer, calmer skin
* A lighter feeling in my body
* Reduced bloating
* A sense of internal quiet
Mentally & emotionally:
* A more respectful relationship with food
* Awareness of emotional vs physical hunger
* A calmer nervous system
* A reminder that rest is productive
Mindset shifts:
* The “health food” industry is often deeply unhealthy
* Reading labels is essential
* Processed snacks — even organic ones — can harm gut and cellular health
* Regular, intentional fasting (done safely) has profound benefits
This wasn’t about deprivation.
It was about listening, learning, and resetting.
I’ll continue to update over the next few days as my energy levels stabilise and improve. For now, I’m deeply grateful – to my body, to the group who supported one another across time zones, and to the reminder that sometimes, doing less allows the body to do more.
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This blog post reflects my personal experience and is shared for educational and reflective purposes only. It is not intended as medical advice, diagnosis, or treatment. Prolonged fasting may not be appropriate for everyone, particularly individuals who are pregnant or breastfeeding, have a history of eating disorders, low blood pressure, anaemia, diabetes, or other medical conditions, or who are undergoing medical treatment. Always consult with a qualified healthcare professional before undertaking any form of fasting or significant dietary change. Listen to your body, prioritise safety, and stop if you feel unwell.