The majority of chronic bowel diseases are primarily controlled by the use of immunosuppressant drugs which have nasty side effects. Consultants rarely offer the use of diet to control diseases such as Crohn's, Ulcerative Colitis and IBS as they lack any awareness of evolutionary nutrition. Neolithic foods (grains/dairy/legumes) are proven in research to cause systemic inflammation, yet hardly any physicians ask their patients to try a paleolithic approach. Instead patients are driven into a cycle of stronger and stronger drugs which eventually often leads to surgery. In my opinion it is akin to a pulmonologist not suggesting his patient give up smoking. Here is a link to the scientific research:

http://robbwolf.com/what-is-the-paleo-diet/science-research/