Kelsay explains that fibre can cause blockages and reduce transit time, while also bulking stool.
A review of research on effects of fiber intake on man.
June L. Kelsay, Ph.D.
Although it is supposed to travel through the gut at a faster rate, it does not always do so and it has been shown to cause blockages.
The inclusion of fiber in the diet resulted in increased stool bulk . Bulkier stooI were reported when wheat fiber bagasse, or cellulose were given, when a diet containing whole
maize, wheat and vegetables was fed, or when fruits were added to the diet.
Particle size of bran did not influence stool weight. In one study of patients with diverticular disease unprocessed bran did not increase stool bulk.
In the studies reported the amount of fiber added to the diet may not have been sufficient to result in decreased transit time .