I found the following blurb in a simulated patient/doctor dialogue in Burstall, Vallis & Turnbull's recent book about IBS (I.B.S. Relief: A Doctor, a Dietician and a Psychologist Provide a Team Approach to Managing Irritable Bowel Syndrome, 1998; page 136). Incidentally, I now recall, that this is the source that provided some very specific dietary recommendations which have helped me quite a bit."Patient: Doctor, I've noticed undigested food when I have gone to the bathroom, especially when I have diarrhea. I am not too suprised about seeing corn, but sometimes I see tomato skins, seeds, or other pieces of fruits and vegetables.Doctor: What you are describing is normal. Fibrous foods such as vegetables and fruits are not completely digested even though their nutrients are extracted by the intestines. Undigested food is just easier to spot in diarrheal stool. Corn can be seen even in normal solid stool because of its bright yellow color, but other undigested foods are in the stool as well. It is not normal to see meat fibers and fat in the stool. This indicates a problem with food digestion. At times you may notice that the normal mucous present in stool looks like fat globules. This can be confusing, but it is rare for the body to be having trouble absorbing fat and not lose weight. If you are losing weight, further testing can be done on the stool to confirm a problem with fat malabsorption."