How do you manage?

My husband and I cook and eat most meals at home. He doesn't enjoy restaurant food much, and we both do our best to avoid vegetable oils, preservatives, etc. We're going to visit and stay with my family soon for a couple of months, and they eat most meals out (Chinese food), and for meals at home, cook with vegetable oil, soy, sauces with preservatives. Almost everyone we know like all the foods we avoid. What do you do when with company and you don't want to eat what they are eating? Especially if there's not much other options.