Foods such as lemons, pineapples, and other acidy foods are more harmful than beneficial to your ulcers. Stay informed by doing more research on these foods so that you know what you should steer clear of. 6. Pasta and Bread. Bread and Pasta are foods that have been processed which is also bad for you if you have a stomach ulcer. Opt for a healthier option when craving these, such as fibre foods and green vegetables. Also drink a lot of water as it will help curb you from craving starches.