ibs4dIBS-D Diet Guide Key Takeaways. The IBS-D and Food Connection: Diet plays a crucial role in managing IBS-D. FODMAPs (fermentable olosaccharides, disaccharides, monosaccharides,Diarrhea-predominant IBS (IBS-D) is a subtype of irritable bowel syndrome that causes frequent bouts of diarrhea with abdominal pain and bloating. IBS-D is considered a