Talking about bodybuilding is futile
This.
Honestly, your average person doesn't really care about this stuff outside of perhaps talking bench or bicep numbers. Or perhaps telling you about their cousin in the slam that could clean and squat #950 before he blew his back out.
Unless someone really mentions something that proves their knowledge, and seems like it might be interesting conversation, I just smile, pat my belly, and go "Ya, I like to lift, helps keep the weight off" or something similar.