It goes without saying that one of the best things you can do for your body is to quit smoking cigarettes. If you smoke, you are inhaling poisonous gasses containing chemicals which no vitamin on earth, and no amount of effort spent trying to achieve good nutrition or a healthy fitness regimen can mitigate. But those of you actively trying to quit this self-defeating habit know how very difficult quitting really is.
Maybe you have tried to quit several times but failed each time. According to those who have successfully quit smoking, there is still hope for you, anyway. Most ex-smokers report that they attempted to quit many times and failed before they finally succeeded. It's a bit like learning to ride a bicycle. You are likely to fall a few times while you are learning, but eventually you achieve mastery of the skills involved.
Through experience, you eventually realize that as much as possible you should avoid those stimuli, whatever they are for you personally, which make you want to smoke. Do you normally smoke while drinking alcohol or perhaps coffee? Avoid alcohol and coffee, at least for a while! Does your mother-in-law make you want to light up an entire pack at once? Avoid her if you can! Replace the negative stimuli with new, positive activities such as mixing and drinking new nutrition drinks and doing exercises to clear out your lungs and sculpt your body. Yoga and meditation in particular are reportedly helpful to many people during this stressful and difficult transition.
Yes, quitting smoking is difficult, but it is not impossible. As the Nike slogan goes, "Just do it!" Your body will thank you.