SB Diet and nicotine
In spite of that fact that nicotine is thought to raise metabolism, it’s poisonous harmful influence on metabolic enzymes is more important.
So definately those people who smoke won’t control their weight this way. And if there are any benefit that might come with smoking, they will be crossed by it’s destructive effects.
Actually smokers really gain weight when they quit, but this might also be caused by the fact that some have in fact a “hand-to-mouth” fixation that they later try to satisfy by eating. If you trying to give up smoking being on the South Beach Diet, this will not influence negatively your weight because on diet you can eat as much as you want.