As @johnbishop mentions in his reply of a detailed response I made recently, I had the experience of EPI and approached my situation in a methodical manner. It was basically keeping a daily journal and fine-tuning my diet at first. The game changer was when I realized I was experiencing EPI and was prescribed a pancrealipase. I was able to optimize the dosage fairly quickly from having recorded observations on what worked for me before medication. I do know of patients having both EPI and another co-morbidity...lactose intolerance, celiac disease or IBS. Through a combination of maintaining a diet of food item that worked and using a pancrealipase in a dosage appropriate for the meal type, they got their GI system back to an acceptable level. When I got my EPI addressed, my quality of live improved significantly. I went from nearly daily bowel issues to normalcy in a very short period of time.

A "go to" person for me was the Registered Dietitian. look for one having the designation CSO (Certification Specialist Oncology). Whether you had a GI cancer or not, the R.D.-CSO has advanced academic training and practical experience in working with GI patients having complex issues. Another good source of information was in calling the Patient Assistance department of the manufacturers of the different pancrealipase products. They are staffed by RN's and RD's and have a lot of knowledge.

The Pancreatic Cancer Action Network has a very informative booklet titled Diet and Nutrition at this link
http://media.pancan.org/pdf/patient-services/booklets/Diet-Nutrition-Booklet-Digital.pdf
Their contact info is 877.272.6226, M-F, 7;000am-5:00pm PT and e-mail: info@pancan.org

The National Pancreas Foundation has a cookbook for free download. It may have suggestions that will work for both EPI and IBS. Their website has contact info and there might be someone to give suggestions on diet and nutrition with the co-morbidities you have. Call 1-866-726-2737 or e-mail
info@pancreasfoundation.org