I think some people probably really do have FI, but I don't think it's the cause of everyone's IBS. However, I understand when someone has had IBS for a long time and nothing seems to help and they are trying to find answers/help. It's probably a good thing to rule out FI. I don't think it's a good idea to obsess over it -- because that would certainly cause a lot of anxiety and that would aggravate one's IBS symptoms. I think people need to remember that diet is only one part of it -- and that we're not using dietary changes to cure IBS or find a cause for it. We're just trying to eat in a way that minimizes over-stimulation of the GI tract.