Just wanted to say I struggled with IBS c for several years. It started when I began taking fluoxetine for pnd. Gp told me that it was an unfortunate side effect, and to drink more water (I was a water-guzzling thing at the time).
I assumed it would go away when I came off the Prozac, but it made no difference.my gp gave me charcoal tablets which just gave me stomach cramps added to the d.
Then I saw a kinesiologist < woo alert > and followed her advice almost to the letter. There was a huge list of 'don'ts,' including wheat, dairy ( of course), potatoes, in fact, all nightshade plants, tomatoes, beef, pork, alchohol, tea, coffee, sugar - the list went on...
I followed that regimen for about 3 years, feeling like a freak and fussy if I went out. It worked like a dream. I started eating normally again by necessity when we were having a new kitchen built and I couldn't be arsed to cook separately for me. I was absolutely fine.
Looking back, I think it's most likely the wheat and dairy that were the culprits. Also one thing she recommended that really made a difference: drinking a pint of warm water on rising, waiting half an hour for breakfast. In fact, only drinking an hour after and half an hour before meals - never drinking with food.
Sounds stringent and weird, but I'm convinced it helped enormously.