Wesley Smith writing at Weekly Standard (via Craig Newmark):
No lifestyle crisis is complete without villains to punish. Just as global-warming fighters want to tax carbon dioxide-producing industries and activities, the anti-obesity campaign calls for taxes on tobacco, alcohol, and “unhealthy food and beverages.” And in places like the United States where it is difficult to restrict speech, “corporate tax deductibility of advertising costs for unhealthy foods” should be eliminated to prevent the obesity pushers from promoting their toxic wares to the helpless masses.
It's fairly common to gain weight after you stop smoking, especially in the first few months — but it isn't inevitable.
Smoking acts as an appetite suppressant and may slightly increase your metabolism as well. When you quit smoking, your appetite and metabolism return to normal — which may lead you to eat more and burn fewer calories. Also, your ability to smell and taste food improves after you quit smoking. This can make food more appealing, which may lead you to eat more. And if you substitute snacking for smoking, the calories may quickly add up.
So we want people to quit smoking so they'll lose weight, but if they quit smoking they'll gain weight. If anything, obesity fighters should advocate cutting taxes on cigarettes to encourage people to smoke.
Related story: my grandfather was a big man and a heavy smoker. In the 60's, his doctor encouraged him to quit smoking so he would live longer. But he gained so much weight after he quit that his doctor later told him to go back to smoking so he'd live longer. He eventually died of a heart attack