Perhaps you can slow down the effects of smoking by doing meditation practices, but damage will be done regardless. I understand that it's impossible to cut it off immediately, so I suggest you start decreasing the amount of cigarettes. For example, if you smoke 20 per day, you can decrease them to 18 and keep decreasing by 2 or more every week. You also need to find something to replace it with, so maybe weight-lifting or martial arts will help.