What foods or additives are the worst to consume if ibs?

It depends.: It depends on whatyou can eat. If you have a problem with foods that are spicy, rich, or acidic, then avoid those foods. You might need to avoid lactose foods, like milk. Avoiding stress and an overall high fiber, bland diet would help a great deal if not already done. A visit to your doctor to get tested, and work out therapy can help.