Thank you for the suggestion!
I should clarify a bit. I eat primarily rice, rice pasta, rice bread and some soft vegetables and fruits (tomato, eggplant, avocado, sweet potato, banana). I have huge problems with substantial protein sources (meats, beans, nuts) and have trouble with fats. I have a lot of trouble digesting just about everything including vegetables with more fiber than an eggplant for example. Food moves through my digestive track at a relatively normal pace, but remains mostly undigested. For example, spinach is completely unaltered by my digestive track. Different foods cause different severity of problems (bad to horrible) and slightly different symptoms. The time to onset of problems after eating varies depending on the trouble food. The stool varies as well. Eating even a small amount of beans or meat would cause huge problems quickly - extreme pain and an entire day to two day in the bathroom.
My normal daily diet includes rice with tomato soup for lunch and rice pasta for dinner. I am very careful about what I eat. Even eating this I have gas, bloating, and at least three trips to the bathroom.
It may be that my IBS is a little bit different than classic IBS. I have constapation only once every other month and it isn't that bad. Generally I have extremely loose stool as opposed to (watery) diarrhea . I do have classic IBS gas, bloating, and sharp pain in the large intestine. There is a particular type of pain with protein.
I take a lot of zenpep and beano. Those may help a little bit. Other medications have not been successful and have actually made things worse. I have not tried accupuncture or hypnosis.
I am skeptical that all forms of IBS have the exact same origin. In my case I think the origin is psychosomatic (based on the particulars of my life). This may not be true for the majority of cases. I do not have a family history of GI problems and I have had a very high degree of stress in my life for at least 15 years. I am able to cope with the stress and have a career. However, it may be that the impact of the stress is IBS.
I think the general phrase of "all in one's head" is a bit misleading. It dismisses the psychological component to illness. It is sometimes used as an excuse to dismiss illness. My impression is that there is a range of degrees to which various illnesses have a psychological component (broken leg - none, tension migraine - very high). IBS in general has a substantial psychological component I think.