If you think you have IBS, stay in touch with your gastroenterologist, who could help you with that. Did the gastroenterologist say you had IBS, or do you think so?
A Naturopath would be able to advise you on a diet, but make sure it's one that is willing to research Body Odor causes. Honestly, I don't think very many people do specialize or have clues as to how to diagnose and treat Body Odor .