So, let's start simple: Should Christians take care of their physical bodies? Indeed we should. I Corinthians 6:19,20 is foundational to this study - "Or do you not know that your body is the temple of the Holy Spirit who is in you, whom you have from God, and you are not your own? For you were bought at a price; therefore glorify God in your body and in your spirit, which are God's." This passage is often used, and rightly so, to teach against smoking and the use of recreational drugs and alcohol. As Christians, our bodies aren't even really our own! Read the passage again. Our physical bodies belong to God; your body does not belong to you! God has made us stewards of the fleshly shell in which our spirits currently inhabit. And what does God expect of stewards? Faithfulness (cf. I Cor. 4:2)! Does a Christian have the right to engage in behavior that is destructive to that which belongs to God? Is smoking being a good steward of one's body? Is smoking a faithful use of the body God owns? It's a well-established fact that smoking damages the body. Many lives are cut short by habitual tobacco use. If one is truly endeavoring to serve Christ and glorify God in his body, how can he smoke? Where does God authorize this destructive behavior? The same type of questions could be asked about the use of recreational drugs and alcohol. If the behavior in question is destructive to the bodies God has given us, how can the behavior be proper?
I realize that some in the past (decades ago) may have been unaware of the damaging effects of smoking, but that's not the case anymore. I firmly believe that a Christian who is addicted to smoking (nicotine) should do everything he can to quit. Will it be easy? Certainly not, but it is a worthwhile and attainable goal. Will it take intense self-control and discipline to stop smoking? Indeed, but any Christian who really wants to quit can do it (cf. Phil. 4:13). Will one who quits suffer withdrawal symptoms and be tempted in the future to go back to smoking? Of course, but they can be successful. If a person can say "no" once, then he can say "no" a thousand times (or as many times as is necessary to remain free from the power of the item in question)! Again, the same basic points can be made regarding the use of recreational drugs and alcohol.
Many Christians who would never smoke, drink, or do drugs, have no qualms about damaging their bodies when it comes to eating, however. Followers of Christ, this should not be! Too many of us consume many more calories than our bodies need, and what is not burned off is stored as fat. From what I understand, having a little bit of body fat is a good thing, but having too much of it is harmful to one's health. So, how much is too much? I realize this is a subjective question. I've answered the question for myself personally (which I'll explain in our next lesson), and you should answer it for yourself, too. In the final analysis, how you take care (or fail to take care) of your body is between you and God. He's made you a steward of your physical body; I'm not in charge of your body. You will answer to Him one day for your behavior; you won't answer to me. So make wise choices to benefit yourself both now and in the future.