My girlfriend, who converted me to being a vegetarian, has been one herself for about 7 years. She often struggles with the "same conversation being rehashed over and over" when it comes time to dine with new people. You mentioning that struck a chord for me. It's very draining!
I try to say as little as possible. There seem to be some distinct lead in questions universally posed by the polite interested individual versus the combative beef-its-whats-for-dinner type.
Polite Person: You're a veg?
Polite Person: That must be hard, I respect that!
Followed by things like, so what do you like to eat? How long etc etc? This is compared to...
Protein Purist: You're a vegetarian?
Protein Purist: Where do you get your protein? (
) You know that the vay-gun (Where do you buy this weaponry by the way?) diet isn't nutritionally complete right? How many different vitamins do you have to take? *Bites into mound of trans fat with veggie side dish eschewed in favor of a double side of fried potatoes*
Me: I do take a multi-vitamin, however I've never felt healthier in my life when I do or don't take it!
Protein Purist: Well, your whole body is going to go down hill the longer you stay with this fad *shifts 350 pound frame over as the cushions in the previous position have deflated* Protein deficiency is very serious you know!
Alright so that was very stereotypical and mean, but they're called generalizations for a reason! In an informal setting I either deflect the conversation or open up a little bit to argument, however in a formal setting I just try and stay polite and wait for the badgering to end or say something like, "Well, I feel really healthy! I appreciate your concern though."
May luck and peace be with you Samsara!