I would go to a bland
diet and add things in slowly to see what effect different items have. You can
journal it. Then you will be left with a safe diet of foods. Fiber in particular can be tricky for flatulence. Be careful with all fiber foods and introduce slowly such as nuts, legumes, breads, cereals, vegetables with higher fiber, etc. Stick to smaller portions too of all meals even if you have to eat more frequently. And as purple stated, lower fat foods are better.