by Alison Harris Recent research points to the idea that IBS may be caused by an overgrowth of bad bacteria in the small intestine. It seems that some foods favour the growth of these bad bacteria and one way to reduce their quantity is to know which foods support their growth. You need to keep a food and symptoms diary as this is the only way you will be able to track down the trigger foods and eliminate them from your diet. The list below shows 2 known foods that definitely trigger IBS s