Hi skinnyninja,
Major congrats on quitting smoking! I know it's a difficult thing to do as I went through it myself.
The only major research I've seen specifically on this topic is this...
USATODAY.com - Obesity greater health risk than smoking
Also, if you compare rates of chronic problems related to smoking around the world, they are fairly low in societies that eat well and exercise, even though they have high smoking rates. In the US, we have a comaratively low smoking rate, but a higher rate of smoking related problems.
It's just an interesting subject given how smoking is demonized so much, yet other lifestyle habits are treated with less emphasis.
Thad