I know it's been a while since the original post, but I wanted to add my two cents. Recently there's been a flurry of information in the media regarding SIBO, small intestinal bacterial overgrowth. I found studies on PubMed showing that cystic fibrosis patients are much more likely to get it because of our impaired digestion. Because of years of bloating and digestive discomfort after seemingly random meals, I figured this might be what I have. I started the Specific Carbohydrate Diet (you should absolutely look at this if you're having digestive / IBS-like issues) and stopped dairy as well as nut butters, which I usually eat in abundance (I was already paleo+ dairy). While I'm certainly not perfect, there have been great improvements. I'm no longer doing the strict SCD, but I'm trying a low FODMAP diet with success. I have a GI appointment in August and am going to request the lactalose breath test, which can diagnose SIBO. This is a great website:
http://www.siboinfo.com. The tendency for CF doctors is to put patients on meds like Miralax or Zantac or Prevacid (all of which have been found in my medicine cabinet at one point), but I really believe that monitoring and altering diet should be the first line of defense.