Do you drink uncaffeinated Diet Coke? As a D type, I find that caffeine is a big stimulant for intestinal contractions. For a long time I drank about a liter of decaffeinated Diet Coke a day, but since I've switched to bottled water because of bladder problems, my IBS has improved a lot. I don't know if it was the carbonation or the Nutrasweet that was bothering me.