Hi chris677.

I'm not a doctor and I have no medical qualifications; however, I've been an IBS sufferer for the last 40+ years, being first diagnosed in my early 20s.  A couple of years ago I went through the FODMAP diet protocol and it identified my particular trigger foods.

Unfortunately, no doctor should diagnose you with IBS until cancer has been eliminated as a possibility.  You really should think about the colonoscopy.  Both my wife and I have had them, and they were fine.  There is really nothing in what you've written to indicate you've got cancer, but the colonoscopy will make sure.  Once you've had that possibility eliminated, (and assuming your diagnosis is IBS) then your doctor can make the necessary referral to someone who can help you through the FODMAP process.  Note that it's so difficult you really can't negotiate your own way through it without professional help.

The problem with any scan is that it can't see everything.  For instance, an ultrasound of the bladder might not see a small bladder cancer, but a cystoscopy will see it immediately.  That's why specialist uses different forms of scanner for different cancer types, instead of relying on just ultrasound.

You sound worried about a something that will involve, at most, 36 hours of your life including time to take bowel prep and have the actual procedure (for which mild anaesthetic is available).  For me that 36 hours is less time than you're currently spending worrying about the procedure itself and the possible outcome.  I don't know you or your other circumstances so can only say if it was me, I'd be booking that colonoscopy!

Thank you . Your right

Point taken 

xxx