Home > Gastroenterology > Diet and IBS Get the Flash Player to see this player. Rate: (Click the stars to rate) Published on Aug 03, 2008 by PWhorwell, Views: 7395 Dr. Peter Whorwell, Professor of Gastroenterology at the Univ. of Manchester, discusses diet and irritable bowel syndrome. Patients with IBS always have symptoms that worsen when they eat. Patients with IBS must avoid fiber, chocolate, and caffeine.