Since I’m a vegetarian, people are often trying to get me to eat things with meat in them (even people that know I’m a vegetarian) so I often have to gently remind them, or explain to them that I don’t eat meat, or fish or chicken, or gelatin or anything that’s cooked with meat broth or itty bitty chunks of meat. Not even tuna fish sandwiches (which some people don’t realize are not suitable for vegetarians). If I’m invited to someone’s home, I usually try to politely and discreetly explain beforehand and then ask if I can/should bring something vegetarian to share with everyone.
I have a tendency to decline invitations to functions or parties or events where I can’t be sure of what will be in the food. I don’t ever want to insult anyone or embarrass anyone or cause a scene. I also carry vegetarian snacks in my purse, for the rare times when there is some type of impromptu meal (like someone at work shows up with a surprise, or everyone insists on going out to lunch at a steak house).
Also, if I’m the one hosting the meal or party, I try to find out ahead of time if there are any foods that are off limits to anyone for any reason and then I try to accomodate them, but I don’t ever feel insulted if someone can’t eat something or doesn’t like a particular food.
On the other hand, if I know for sure that the food is completely vegetarian, but someone really wants me to try their eggplant, I will choke it down. Eggplant is the one veg food that I just don’t like, but I always give it the old college try.