Agree with many of the comments listed above, particularly a low FODMAP diet as a place to start….the good ol' elimination diet!
My IBS, a condition which, by the way, can be hard to diagnose, has gotten worse over the years, so I recently met with my Dr. to discuss options. She ordered for me to take a SIBO (small intestinal bacterial overgrowth) test; it's a non invasive breath test, but must be prepared for & meticulously executed over a period of several hours; it is done at home & FedEx’d to a lab. Anyway, for me, the results came back in "moderate" range and can account for many of the more intense symptoms I’ve been experiencing. SIBO has a tie-in w/ IBS, or so the current thinking has it. I have not yet started the treatment; there are two medications prescribed (and my insurance company had to approve them) and is followed by several months of a VERY restricted diet & I wanted to wait until after the holiday season and all the food-abundant gatherings there are!
Anyway, I post this as added information to what others have offered. Maybe other readers might want to look into SIBO as a possibility, as there are many conditions surrounding the gut that can mimic others. Researching it and discussing options with your physician is a start. I’m lucky that my Doc is a holistic practitioner (she’s the one who suggested the test….I’d never heard of SIBO before) & willing to work with me.
Here are some sites that may be helpful:
Heather’s site for IBS related stuff (someone else mentioned her products on this thread); you can sign up for her newsletter, which is helpful, as she passes along the latest findings & has good advice; I use her Acacia Senegal soluble fiber and peppermint capsules (I buy my own bulk fennel seeds from the local co-op to make fennel tea)
http://www.helpforibs.com/news/
An abstract from the National Institute of Health on SIBO
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3099351/
I ordered a book ‘The SIBO Solution’ from them; it mentions FODMAP as well as having lists of OK and not OK foods while being “treated”. I don’t know that one would necessarily buy the book if there is not a diagnosis (particularly the medical-treatment phase), but it’s worth checking out the website. It is written by a lay-person, not someone in the medical field, and is based on her journey through the process.
https://hollywoodhomestead.com/sibo-solution/
Hope this is of use to someone out there in online land....