A waste of time unless they're ready. You'll hear nothing but lies, excuses, BS, and probably alienate someone. Even worse... you'll end up hearing"I should have listened".
I tried for years to get my sister to do something about her weight. Got every excuse from "I love food too much" to "The bible says it's not what goes into the mouth that condemns a man but what comes out of it" and an opinion that the Lord blesses everything Christians eat so there's never any need to be on a diet, LOL! Now her fat ass is on metformin, LOL! When the topic comes up "Keep eating, they'll just give you insulin and other drugs" is all that gets said. It's what she wants to hear and I'm not wasting time giving advice she won't follow.