I know this is an older thread, but I`d like to chime in here with my $.02 as well.
I quit smoking 15 months ago (wow, the time FLEW by) and I just started my weight loss journey 4 months ago. It took me a long time after I quit smoking to be able to focus on something else... although a HUGE part of that was just pure laziness! I gained about 5 pounds after I quit smoking, over the course of a year. However, the vast majority of that (4 pounds ish) was from holiday weight, LONG after I quit, and really had nothing to do with smoking.
I don`t miss smoking AT ALL anymore. I used Zyban and Nicorette. I quit the Nicorette two weeks after quitting smoking. I did a LOT of research on quitting methods, and did what felt best for me and my body. I went through a workbook put out by the Canadian Cancer Society, and planned my butt off! I basically became OBSESSED about quitting smoking, talking to everyone I could about it, thinking about it all the time, planning incessantly. This may not be the best method for everyone, but it felt right for me, and it`s worked. It`s also the way I approach my weight loss.
You do NOT have to gain weight after you quit smoking. I was paranoid about this as well and so planned, planned, planned and made a big list of things I could do other than smoke.
A few of the key things that helped me were (yes, some may seem weird, but they really helped):
1. Drinking very cold water through a straw that I had pinched with my fingers -- this gave me the same feeling in my mouth and throat that smoking did and was my No. 1 replacement.
2. Chewing sugar free gum -- I STILL chew a LOT of gum. It`s primarily out of boredom and habit now, but it`s a much cheaper, and healthier habit than smoking!!
3. Deep breathing
5. Changing up my routine
6. Closing my eyes and picturing things that made me happy -- my boyfriend, my dog, laying on a beach, etc.
I also feel that the biggest thing Zyban did for me was help keep me positive about the whole experience. I was able to maintain a very positive attitude throughout, which for me was key (I have a history of severe depression). This makes sense since Zyban is actually an antidepressant (buproprion, aka Wellbutrin).
HTH a little.