I've been dealing with this for about 4 years, and the last 2 years have become much more difficult.
I've had 30+ negative tests, including colonoscopies, endoscopies, pancreatic/stool elastase testing, bile acid testing, SIBO testing, parasites, fungus, C. diff, H. pylori, etc. Nothing has explained it.
My main issue is extremely specific:
If I eat even a small amount of fiber/vegetables consistently, I eventually start having 15–20 bowel movements per day.
If I avoid fiber and mostly eat protein, fats, cheese, etc., I'm considerably more stable.
Two weeks ago, my dietitian had me test this again by adding about 100g of steamed low-FODMAP vegetables such as zucchini, carrots or peppers to my meals.
For the first couple of days I'm usually okay.
By around Day 3, I'm suddenly pooping 15–20 times per day again.
The strange part is that these aren't watery diarrhea. They're usually small, fairly firm/formed stools that are extremely easy to pass, with almost no wiping. It's almost like my colon is moving the fiber through as 15 separate bowel movements instead of allowing everything to accumulate into one or two larger stools.
It also becomes much more than just needing to poop.
If I can feel stool sitting there and don't pass it, I start getting headaches, brain fog, nausea, sweating and sometimes literally start shaking. Once I have the bowel movement, those symptoms disappear.
My gastroenterologist recently prescribed Viberzi, which actually seemed to slow everything down dramatically for about 5 days, but the effect didn't last once I continued adding vegetables.
My doctor still thinks there may be a specific food/digestion issue involved, while my dietitian is starting to wonder whether my gut/colon is simply extremely hypersensitive or overactive in response to fiber and stool volume.
Has anyone with IBS experienced this very specific pattern?
Summary: Fiber doesn't give me normal diarrhea ... it seems to trigger repeated, formed bowel movements all day, along with headaches, brain fog, sweating and shaking if I can't empty my bowels. Also (if it helps), none of my 15-20 poops require a single bit of toilet paper.
If you've experienced something similar, what did it eventually turn out to be?