1. I haven't heard that.
2. It varies from person to person as to what they can and can't eat. For example, I can eat pasta sauce, beef, and veggies (cooked) without much of a problem. But for many, these are no-no's. You need to figure out what your safe foods are. I suggest keeping a food diary. Record what you eat and your symtpoms. You'll eventually see patterns of what upsets your stomach. But if you want to play it safe - stick to a low-res diet such as baked/grilled chicken, rice and potatoes.