Excerpts from: "The Long Hollow Tube – A Primer on the Digestive System" by Sally Fallon.
The lining of the large intestine is as smooth as the inside of the mouth. Contrary to widely held belief, only in cases of severe illness, such as cancer, does fecal matter remain stuck to the wall of the bowel. Even in the elderly, the feces pass through the smooth wall of the bowel without sticking. Except in very high fiber diets, the bulk of the feces is made up not of fiber but dead bacteria.