Thou shalt not murder..... smoking and drinking - (in excess causing liver problems and can't live without a liver) - same as murdering yourself albeit a slow process. Our bodies are the temple of God.... I am sure He would prefer smoke free clear mind and correct weight. I am as guilty as the smokers being over weight. I include myself in this mess of sin.
Then there is the other one of Thou shalt not have any idols or any graven images... in other words put something anything before the Lord and if we and I say we..... If we say we can't quit whatever our problem is are we then saying that the problem is stronger than the Lord? An idol possibly?