As for the weight loss, I think go ahead and mention it but make sure it is about an increase in attention to personal health, etc. It shows commitment and real change. If you're still pretty fat during the time of the interview you may want to explain that you're still losing weight steadily.
I have different opinions about the smoking. I think if you quit you should mention it if it flows with your story. Again, it shows that when you took an interest in medicine, it reflects on your health.
While it may look bad by some committees, others might like it and identify it as character and unique. But if you want to be safe and cookie-cutter, then take the advice from those above and don't mention it.
Accepted! D.O. 2017