So here’s what you do say, “I’d love to talk about it later if you’re still interested.” Or, “let me send you a link.” You take the subject off the table so to speak.
This is very good advice. It has been my long experience as a vegetarian that it is always, ALWAYS the carnivores at the table who bring it up. You sit there with your vegetarian option, just pleasantly enjoying your meal and the company of others, and boom, somebody drops a bomb between mouthfuls of steak, “So, you’re a vegetarian? I guess that makes me evil, hey?”… open mouthed chewing of dead animal body parts, and crazy eyes that say he’d eat you if he could… I’ve ruined a lot of meals for a lot of people over the years by taking that bait. But I, too, eventually learned to say, “It’s complicated. We can talk after dinner if you want.” Not one single time has crazy eyes ever pursued the conversation later. They weren’t actually interested in why I chose vegetarianism. They were preemptively defending their carnivorism with the tact of a Twitter troll. A straightforward, honest response in the moment to troll bait is rarely the best option.