I don’t really fast for long. 36-48 hours every 1-2 weeks. But I find that anything longer than 20 hours I get some diarrhea when I break my fast. Additionally, if doing a 36+ the diarrhea will last for like 3 days after.
It’s not explosive. Just don’t trust a fart and all is well. But the stools are always loose.
After getting back into the 16:8 or 18:6 routine I find that things return to normal after a few days. If I add psyllium husk it normalizes faster.
Anyone else? How long does it take you to recover?
Sometimes this is related to your gut microbiome. I would try refeeding with raw, unpasteurized cheeses (fermented), probiotic yogurt, fermented veggies like sauerkraut, pickled garlic, pickles, etc. Just watch out for hidden sugars. Scrutinize the ingredients, as always.
In addition to what you are already doing, rebuilding your gut microbiome would help a lot, and not only in terms of your BMs
Anecdotally, this always happens to me too. Unless I only re-feed with fiber ONLY.
If it doesn’t cause a disruption in your life I wouldn’t worry about it.
My theory is that it has more to do with the amount of liquids in your stomach than anything else. I can fast and not have a bowel movement for 2 days and then when I eat, within an hour I have to visit the toilet. My guess is that all of the “excess” water I’m drinking to help my stomach feel full is being rapidly pushed out when actual food arrives. Some weeks I was eating crap, other times I was eating really healthy. No difference in the poops.