Background: Postprandial symptoms in irritable bowel syndrome (IBS) have been associated with increased bowel contractility. Aim: To compare ileocolonic and colonic responses to feeding in health and IBS. Methods: We prospectively analyzed data from separate research trials in 122 IBS patients and 41 healthy volunteers. Ileocolonic transit (ICT) was evaluated before (colonic filling [CF]3h) and immediately after (CF4h) a standard lunch at 3 h 45 min, and 2 h thereafter. The colonic geometric center (GC) was calculated 2 h (GC6h) after lunch ingested at 4 h (GC4h) and directly after (GC8h) a standard dinner ingested at 7 h 45 min. Results: ICT immediately after eating was higher in IBS diarrhea predominant (IBS-D) patients than in the healthy cohort (23.1 ± 2.4 vs. 17.5 ± 2.8%, P = 0.059). ICT 2 h after lunch was similar between groups (P = 0.55). There was significant overall group differences in colonic transit 2 h post-lunch (P = 0.045), particularly in the IBS constipation predominant (IBS-C; GC6-GC4, Δ0.29 ± 0.08) patients versus healthy volunteers (Δ0.56 ± 0.12 GC units). Conclusions: After feeding, ICT is increased in IBS-D, whereas colonic transit is blunted in IBS-C.