I did a 3-day water fast. My body had thoughts.

The other week I caught it — one of those rare, almost suspiciously well-timed windows where everything lined up just enough for me to finally try a proper three-day water fast.

On Sunday I drove my wife and kids down to their grandparents and stayed the night myself. The plan was always to head home alone on Monday for a packed week: long home-office days plus a bunch of basement renovation that had been waiting for me. I already had a solid stash of electrolytes at home, I drink a stupid amount of water anyway, and I knew the workload would keep my brain busy enough that I wouldn’t just sit around thinking about food all day. It felt… right. Not reckless. Just the first time the stars had actually aligned for this particular experiment.

I’ve been curious about extended fasting for a while. Not because some influencer told me it would fix everything, but because the idea of giving my body a proper break from constant digestion sounded strangely appealing to this thirty-something dad who’s trying to keep both his protein intake and his pixel-game-dev side alive. So I had a last proper lunch at the grandparents’ table on Sunday at noon, started the clock there, and drove home the next morning to get on with it.

What the body actually does

Before I get into what actually happened, here’s the part that still fascinates me — and to be clear, this is my understanding of it from too many late-night rabbit holes, not a medical degree: what the body does when you simply stop feeding it for 72 hours.

The first 12 hours or so are pretty straightforward. Your body burns through the easy glycogen stores in your liver and muscles. Blood sugar drops, insulin falls, and the hunger pangs show up right on schedule. It’s mostly mental at this point — your brain is loudly reminding you that lunch is a thing that usually exists.

Between hours 12 and 24, the switch starts. Glycogen is basically gone, so the body flips over to fat for fuel and begins making ketones. Human growth hormone creeps up. This is also the classic danger zone for someone with my migraine history — the blood-sugar rollercoaster and electrolyte shifts can hit at the same time.

Day two (hour 24–48) is where things usually get interesting. Ketosis is properly underway, autophagy (your cells’ internal recycling crew) starts working overtime, and a lot of people report that the hunger actually eases off. The body seems to accept that food isn’t coming and settles into a different operating system.

By day three (hour 48–72) you’re deep in it. Autophagy is running hot, some research hints at broader cellular repair signals kicking in, and there’s often this strange, quiet calm that settles over everything. You’re running on a completely different fuel mix now.

That’s the theory, anyway.

Day by day

Here’s how it played out in real life, in the body of a thirty-something guy who still gets migraines if the wind changes direction, the temperature shifts three degrees, the barometric pressure decides to have a personality, or it’s just a Tuesday.

Day one — the polite warning

Started smoother than I expected. I’d taken electrolytes before leaving in the morning, and by the time I got home and settled into work, the fast was already well underway. The morning flew by in work calls. Around 2 p.m. I made my one daily black coffee — no milk, no nothing, just straight — which quickly became the most exciting event of the day. I sipped electrolyte tea all day alongside it, though I’ll admit that was sometimes a challenge: I have a tendency to be generous with the powder, and at a certain concentration it starts tasting less like a health drink and more like a punishment. I drank it anyway.

Around early afternoon — roughly the 24-hour mark — the migraine showed up anyway. Not a full-blown beast this time, more of a polite but firm warning. I took my usual medication straight away, kept the electrolytes coming, and drank water like it was my full-time job. The combo worked: it stayed manageable and faded by evening.

I still managed a solid work day, then headed straight down to the basement for several hours of wall renovation with music blasting. The heavy physical work actually helped — it kept my mind off the hunger and gave me that satisfying “I’m still doing something useful” feeling. By eleven I was in the bath. I’d had vague plans for the evening — maybe write something, maybe get an hour on the Steam Deck, maybe actually relax like a person. Instead I just lay there doom-scrolling because I had absolutely no momentum left for anything that required a decision. In bed by midnight. Tired, a bit dazed, but still in the game.

The kids had been sick and difficult for the better part of two weeks before this — the kind of stretch where you catch yourself quietly daydreaming about an evening with nobody needing anything from you. But lying there in the silence, the irony landed cleanly: I missed the whole routine. Bath time, the same books, the small negotiations about which pyjamas, the goodnight that somehow always takes 45 minutes. Those things I’d been half-looking forward to escaping had apparently become load-bearing parts of my day. Not habits. Something closer to needs.

Day two — bikes, meetings, and actual clarity

I woke up early — earlier than I needed to — and decided to finally fix my bike. It’s one of those things that never gets done when the kids are around; there’s always something more urgent, louder, or in need of a snack. But with a good stretch of warm weather coming I wanted it ready: one of our favourite things is loading one of the kids onto the back seat and just wandering the city together. No agenda, no hurry — just the two of us rolling past fountains, playgrounds, random corners of town we’ve never stopped to look at properly. They love it. Honestly — so do I.

The bike got fixed. That felt like a small win. And somewhere between the tools and the grease I’d noticed: the hunger had changed. Same routine as the day before — electrolyte tea, the 2 p.m. black coffee as a small ceremony, water constantly — but it wasn’t gone so much as quieter. Less urgent. My energy felt surprisingly solid. The workday clicked along better than most normal days — that clean, uncluttered mental clarity I’d read about was actually real. Not superhuman focus, just… less background noise in my head. Some of it metabolic, some of it the usual parade of meetings that exist primarily to discuss when the next meeting should be. When those dried up and I was finally left to actually work, things moved. I got through more tasks than I usually do.

In the afternoon I went for a gentle 40-minute walk because the weather was too nice to waste. Later I was back in the basement finishing the walls, music on, tools in hand. Another bath, another early-ish night. No migraine. I was absurdly grateful.

Day three — the day that just passed

By morning the hunger had almost completely stepped back. My body had clearly accepted the situation. I felt light — not weak, just unburdened. The electrolyte tea, the black coffee at 2 p.m., the water — by now these were just the rhythm of the day, unremarkable. I spent most of the day on programming work, then did a very light training session in the afternoon (in hindsight I was more fatigued than I realised, but it still felt good to move).

Honestly, day three is hard to describe because not much happened — and that was the point. It just passed. Quietly, easily, almost without effort. At some point I realised I could probably have kept going another day or two without much drama. The hunger was gone, the energy was steady, and there was a strange simplicity to the whole thing.

But I knew what was coming. In a day I’d be back with the kids — wonderful, chaotic, relentless small people who would cheerfully consume every last bit of my mental capacity within the first twenty minutes. So I played it safe. At exactly the 72-hour mark I broke the fast with bone broth, added a few bits of carrot and a boiled egg, and ate slowly in two small portions spaced two hours apart. Nothing dramatic. Just careful, respectful — and honestly, a little strategic.

Then I packed up and drove to pick up my family. I’d missed them like crazy. Two days of quiet house suddenly felt way too quiet.

The migraine question — because I know a lot of you deal with the same thing

If you have chronic migraines and you’re thinking about trying this, I want to be straight with you: the first 18 to 24 hours are still your highest-risk window. There’s no way to eliminate that risk completely. What helped me this time:

• Electrolytes, especially sodium and magnesium (magnesium glycinate was my MVP again)
• Drinking a ridiculous amount of water
• Having a real exit plan: if it had turned ugly, eating would not have been failure — it would have been the sensible call. I’ve broken shorter fasts before for exactly this reason: I felt the warning signs building and knew that if I pushed through, I’d lose the next two or three days to a full migraine. That’s not discipline. That’s just bad maths.

Was it worth it?

Honestly? Yeah. With caveats the size of a house.

The day-two clarity was real and I’d like to chase that feeling again sometime. I slept deeper on nights two and three than I have in months — though I’ll be honest, I’m about 40 percent sure that was the ketosis and 60 percent sure it was just the absence of a small person climbing on my face at 5 a.m. In the week since, I’ve been noticeably more tuned in to how different foods actually make me feel — not in a preachy way, just a quieter, more honest conversation with my own body.

Would I do it again? Ideally every three months or so, with the same careful prep. Not on a weekend when the kids need me fully functional. Not during a genuinely stressful work stretch. And I’ll always take the migraine risk seriously. Whether the stars will actually align that often — well, that’s a different question entirely.

Thinking about why it went as well as it did — I think two things helped beyond the electrolytes and the planning. First, I was genuinely prepared: I’d read enough, thought it through, and went in with a real exit strategy rather than just willpower and hope. Second — and I’ll admit this freely — I’m probably a bit of a natural introvert. Three days of quiet, useful solitude, left entirely to my own devices, working with my hands in the basement and my brain in the code… that suits me in a strange way. The fast slotted into that headspace almost naturally. It felt less like deprivation and more like a slow, deliberate kind of meditation — my own small island, but a productive one. The days weren’t empty. They were just quieter and more mine than usual.

Seventy-two hours. Water, electrolyte tea of dubious palatability, a fixed bike, and a basement that’s significantly less unfinished than before. I came out the other side a little lighter, a little clearer — and absolutely certain I was ready to stop being alone.

That feels like enough.