In a sense I wouldn't berate coworkers and family for smoking and drinking stating facts about the detriment to their health every chance I get. I'd lend a hand when they need me the most, when they've looked in the mirror long enough, when they are looking for change.
It's a fact I've come to realize some people don't want to change others have a limit they reach before they can change. If your always there to help when they need it, the outcome will almost always be better.
I don't like being told what's best for me or what I should be doing as much as the next guy so I don't really bring it up unless they ask.