One thing I’ve learned during the 12 years or so this blog has been running, is that there is always going to be a gap between the plan and the reality. Shit will come up that you didn’t expect. Literally.
The “Global Rollout” Error
After my December “reset,” I felt invincible. I’d lost over 12lbs, my treadmill runs and swims were consistent, and I was ready to start fasting in earnest.
So, I decided to jump straight into a 36-hour fast.
Mentally, I was ready. I’ve done this before. I know the drill. But there’s a gap between Mental Preparedness and Biological Readiness. If you’ve been “drifting” for many months without regular fasting, you may find that your digestive system is no longer the high-performance fasting-ready engine it once was; it’s more like a rustbucket that’s been on the drive without regular servicing. When you suddenly demand 36-hour performance, you may find the “plumbing” is no longer up to the task.
When the Strategy Hits the Fan
Without getting into the “nitty-gritty” details that even a blog like this doesn’t need, let’s just say that my first attempt at a long fast recently resulted in some… urgent tactical retreats. Brown alert!!
It was a stark reminder of something I’ve always maintained: extrapolating clinical theory into real-world practice is messy. Jason Fung, who I used to be a proponent of but since have become somewhat critical of, talked about the “metabolic switch” to fasting, like it’s a clean flick of a button. In reality, for a Type 2 diabetic body that is currently dealing with “molasses-thick” blood (79mmol/mol), that switch can be more of a detonator button!
The Science of the “Fasting Shock”
So, what actually happens when your gut rebels during a long fast? It’s simply a natural biological response to a sudden change in the comfortable status quo.
In many fasting circles, you’ll hear people claim that the gut simply “rests” during a fast. But for a Type 2 diabetic body transitioning back into 36-hour cycles, the reality is more complex. My symptoms, which included a number of very rapid and urgent bowel requests to visit the littlest room, started about 20 hours into my fast. Obviously, with no food in my gut, what came out was a lot of liquid and nothing else! It was unpleasant to say the least.
Here is what was likely happening under the hood (I should add – I am not a doctor or nephrologist (like Jason Fung), the below is sourced from multiple AI engines after discussing my experience – so take it all with a pinch of bone broth!):
- The “Migrating Motor Complex” (MMC) on Overdrive: Think of the MMC as the gut’s “janitorial crew.” When you stop eating, the gut’s ‘janitorial crew’—the migrating motor complex—kicks in, sending cleaning waves through the small intestine between meals. It’s literally described in the literature as an ‘interdigestive housekeeper.’ In my case, it felt less like a gentle tidy-up and more like a full site clearance. That’s my subjective opinion anyway, not a textbook claim!
- The “Diabetic Gut Chaos” Factor: With an HbA1c of 79, my whole system is running hot. Long‑standing Type 2 can cause something called autonomic neuropathy, which basically means the nerves that control gut motility get glitchy. When that happens, you can swing between sluggish digestion and sudden, watery urgency, especially if you throw a long fast into the mix. The reality is probably a messy cocktail of diabetic gut dysfunction, dehydration, and a system that wasn’t ready for a 36‑hour curveball.
- Electrolyte Dumping: When you fast and insulin drops, the kidneys start dumping sodium and water. That’s part of why people feel lighter and see a quick drop on the scale early on. In my case, that fluid loss, combined with an already irritated gut, may have tipped things toward a ‘system flush.’
The bottom line (pun intended) is that I was able to continue my 36 hour fast to completion the next day despite the occasional discomfort, and perhaps naively, I assumed that simply putting food back into the system would act like a “reset” button. I figured the “janitorial crew” would stop their aggressive sweeping the moment the “deliveries” started arriving at the loading dock.
I was wrong.
I broke the fast with what I considered a “gold standard” diabetic meal: a high-protein Greek yogurt smoothie with whey protein, berries, chia and flax seeds, keto granola and nuts. Nutrient-dense, low-glycemic, and full of healthy fats.
I followed that up a few hours later with a mushroom and spinach omelette.
The result? More urgent bowel requests!
- The “Fiber Bomb” Effect: When your gut has been in “flush mode” for 12 hours, the last thing it wants is a sudden hit of high-fiber keto granola and nuts. Fiber requires significant processing and water. My colon was already irritated and dehydrated from the mid-fast “flush”; adding roughage was like sending a sandpaper scrub through a raw wound.
- Fat Malabsorption: After 36 hours, my gallbladder would have had plenty of time to fill. Hitting it with a high‑fat, dairy‑and‑nuts smoothie could easily have triggered a big bile release. Excess bile in an already-irritated gut is like pouring chemical accelerant on a fire—very plausible that it helped my ‘healthy’ breakfast exit the building almost as fast as it entered.
- The Delayed Reset: I learned that once the “Digestive Pendulum” starts swinging that wildly, it takes more than one meal to stabilize it. Even though I was eating “right” for my diabetes, I was eating “wrong” for a compromised GI tract.
Tactical Adjustment: The “Bland & Bulk” Protocol
The lesson? Simply putting food into a fasted system is not a cure-all. It takes time for things to recover.
And what you put in matters. I would have been much better off to start with the omelette, since eggs are a very readily digestible protein, that would have acted as a bit of a buffer. The fats in the eggs coat the stomach and small intestine. If I’d later followed up with the smoothie 2–3 hours later, the “janitorial crew” would have stood down, and my gut would have been ready to absorption nutrients rather than having a major reaction and deciding to flush everything.
For dinner that evening, after my initial refeed, I had some air-fried cod and vegetables – butternut squash, carrots, and more spinach. Very mild, no spices to set my stomach off. That helped provide the “bulk” to slow things down and begin to regulate everything.
By the next day I was feeling much better and was able to try a treadmill run (still feeling nervous about the pool!) but the run went fine, so I considered myself over the worst.
The cost of a silly mistake
All this didn’t come without a cost. I was due to go for a swim the evening when my gut problems first occurred, and I had visions of a brown cloud following me down the lane! Nuh-uh! I thought about switching to a treadmill run but I was finding that sometimes even walking was enough to jog my bowels into action. So I took a complete break from exercise for two solid days. It was a setback, but definitely better safe than sorry.
Will I adjust my strategy?
Yes, although only slightly. I am still continuing with 36hr fasts, but I started the next one (yesterday) gambling that my initial 36 hour fast and subsequent clear out will have gotten me used to things again.
The adjustment I made was to “see how I go” with a view that if I had any repeat of my upset stomach I could always end the fast early with a more sensible first meal – whether high fibre and protein meal (cod and veggies) or an omelette.
But at this point I’m now 24 hrs into my 36hr fast with no issues at all. I went for a swim this evening and again, no problems.
Certainly an important lesson learned for the future – be very wary of jumping straight into longer fasts when you’re out of practise – there may be consequences! I should have listened to the very loud message my body was sending me and ended my fast as soon as I had issues. I suspect if I had, my recovery would have been much quicker, and the impact to my exercise plan much less.
For obvious reasons, I was keen to push ahead with the longer fasts to get the maximum results, and was not seeing the bigger picture, that sometimes it’s better to take things slow and easy.
Hopefully, I’ve now adapted and, my system will settle into a steady routine as I did before, but I’ll be keeping a closer eye on how I’m feeling through these longer fasts.
Obviously, we will see tomorrow if my new refeeding strategy works – omelette first!
Tomorrow I’m also going to have an early weigh-in – given how much flushing I did of my system, I am rather hoping there will at least have been some benefit in terms of weight loss to make it all worth while! 😀
More soon!
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