I eat before I go and then just have a glass of wine. What made a difference with my mom is when I said, "I am comfortable with it. What I need is for you to be comfortable with it." To the server, I say I already ate, but want to visit with my friends, so I'll just have a glass of wine. Some extended family members have talked behind my back (is she anorexic? do we need to to an intervention?), but if it wasn't that it would probably be something else. It is what it is.
We're going on a 3-day trip soon and I will be packing my own food. I've been surprised how much I can enjoy going to a restaurant without eating. I can focus on the conversation and relax. It's also a money saver LOL.
Thanksgiving, Easter, whatever, I bring my own food. (Christmas is at my house - yay!)
Printing out info on cross contamination may help. That's what I did for my husband.