I agree with tiss that the doctors don't seem to really know the best diet when it comes to missing the ileocecal valve (unfortunately), but I've been working with a GI dietitian for about a year and she has been really helpful regarding diet. Even though she doesn't know the perfect diet for people like me, she does attend lots and lots of GI conferences where they go over the latest research on SIBO and other tricky gut issues. Because of that, she's super well informed so I usually trust her to at least tell me what is and isn't backed well by current scientific research. She said that right now the best evidence-based approach for treating SIBO is still the low FODMAP diet, plus antibiotics and meal spacing. That's what I've been doing lately, and it actually seems to be working pretty well so far (thanks to @tiss for the info about going back on Rifaxamin indefinitely, which I think is a big part of why it's working).

At one point, I asked her about the Specific Carbohydrate Diet since I read a lot about it and it sounded really promising to me, but she said it wasn't based on good evidence. I tried it anyways and it didn't work, so I'm guessing she was probably right. I also asked her about the medicine Atrantil since it sounded really promising too, but she said the research wasn't good on that either so I didn't get it. It can be really hard to figure out what's a fraud or not sometimes...I've definitely spent money on some things out of desperation that ended up being totally bogus.

I also asked her who is the best, most trusted person in the field right now in terms of research on all this stuff, and she said it's Dr. Mark Pimentel, out in California. It looks like his lab has been doing a lot of groundbreaking research in these areas: https://www.cedars-sinai.edu/Research/Research-Labs/Pimentel-Lab/ He also has a Twitter page, where I saw some pretty interesting success stories of people with weird/unique gut issues that he was able to help. If the Rifaxamin and low FODMAP diet stop working for me, I may try to see if I can find a way to go see him someday, though I'm not sure how seeing a doctor out of state would work. Unfortunately there don't seem to be many doctors in general who are well-versed in SIBO or missing ileocecal valves at all. I asked my GI doc here if there were any local SIBO specialists or anything he said no 🙁

Anyways, sorry, long post, but just thought I would shared what I've learned so far 🙂 !