Bottom line is, he's got to want to alter his behaviour patterns. He may find a nasty situation occurs with his health otherwise, but if you cave in to his mentality, you'll end up copying it, which won't help you. Sometimes people have to have a wake up call, before they take notice of things they're doing wrong.
It's not good for the other person living with knock on effects, but it may come to that, if he cannot reconcile his behaviour as no good for him, or for your emotions. It's a question of what will he sacrifice for his health and the love, that is supposed to be proliferating in the relationship.
It's one thing to care, but another to pressurise and if you tip him too far one way, he could resent it and it could damage the relationship, because he could think you've changed if sudeenly your on his back for things more than usual, or being to strident about broaching the subject instead of being more subtle and conservative.
If it comes to the crunch, that he just refuses to accept what might be potentially happening to him physically, with some of his life choices, you may have to settle for it, until there's some possible fallout, then be expected to be there for him when it does.
Otherwise, you'd have the middle ground option, where you subtely persuade him to change, or the drastic option, where you say to him that it's either his way, or in relationship terms, no way and tell him that if his choices damage his health, why should you be there to pick up the pieces for him, because selfishness of any kind, is not a prerequestive of love, like trust, honesty, openness etc etc are
You need to decide how to approach this, with either an acceptance approach, subtle approach or hardcore approach, because ultimately you are getting some unwanted emotional negativity from this, but you might create a situation where it gets worse if you can't try to encourage a resolution you'd prefer, in the right ways.
The fact you care enough not to just sit back and let this continue for his sake, says a lot about you. You clearly have a very good heart, it may just simply be a question of how much he respects it.