I've suffered greatly when people I've cared about deeply, have chosen self-destructive habits. As far as I have been able to trace this back, it began before I was old enough to really know what was happening. My dear Dad chose to refuse the good advice of his doctor to lower his dangerously high cholesterol by eating less meat. A year later, that choice killed him.
The grief & terror of losing such an important person while I was still dependent continues to vibrate within my roots. It was a fundamental influence when I had a child of my own, part of my motivation to go vegan. Thankfully, my hubby felt/feels similarly. So we changed our diet, resolved all the health issues that were limiting our potential, successfully raised our excellent off-spring and are now entering our Golden Years in good health. So that's a happy ending.
Even so, it still bothers me when others decline to make healthy choices. Is that because I was sensitized at an impressionable age, to the very real destruction that faulty diet can wreck in a life and a family? Probably, at least in part; I often seem to be more keenly aware than others that the worst CAN actually happen. I understand in my very bones that having the so-called "just a little" of the wrong stuff really can hurt.
So that's the nurture angle. By nature, I also have a caring personality. It can be one of my finest qualities; it can also be one of my worst! It can cause me a lot of pain, and I can all-too-easily become "a pain" to others. I have sometimes said more than I maybe should have, all the while thinking "If only they had more information, they'd make a more self-caring choice."
Sometimes that is true. Sometimes it does make a difference to say a little more, thank goodness! I've found that it helps to always do my best to be factually accurate & respectful in how I say it. It helps, whether the person is willing to consider what I have to say, and when they aren't. I've needed to learn courage, to trust that everything can be all right, even when a person has said a clear & decisive no.
I've realized that people sometimes come around to a way of thinking later, if/when they are ready. I believe we are created by a Wisdom that only knows Perfection, and therefore, beings of Perfection are at our core; we are only wearing a mortal body. Our bodies our prone to addictions, which can be distracting from the Path favoured by our Core Perfection: loving kindness, joy, The Light.
So I've learned to generously give my best then let the person go with a blessing. For example "I trust the Light Within to lead us both on the Path of Health in all our choices." I've also learned that I can exit the conversation gracefully while opening a window for the other person to change their mind, just by expressing my feelings. For example, "I love you & respect your right to make your own choices; and I feel very sad about you making that one. I hope you make a healthier choice ASAP."