I've lost about 120lb from high school (320->200, I'm 6'4 and 28 now). I also currently smoke. I've quit smoking for about a year and a half, probably 3 of the last 8 years combined have been not smoking. Smoking is harder for me, as it not only requires a pretty vast social adjustment (avoid smokers at first, pass each and every willpower check), and stress brings it out of me like crazy. You need to have something else to replace the quick shots of dopamine you can get any time you want. I am currently working on new habits, and have my diet under control again after gaining some of that weight back. Next is exercise. One thing at a time.