Multiple studies have shown that regular smoking deadens the senses of smell and taste [source: National Cancer Institute]. The exact reasons for the changes are still murky for scientists, and not all smokers experience the decrease in sensitivity as much as others, or even at all. But many smokers find that their appetites increase after they stop smoking, and they are able to enjoy foods more than they used to. That change usually only takes a few days. Possible theories to explain the improved palates of ex-smokers include constricted blood vessels in the nasal passages and taste buds becoming flattened from exposure to smoke.
Smokers should be careful about overindulging their newfound appetite, though. Nicotine speeds up metabolism, so after quitting, most smokers experience a few pounds of weight gain. On top of that, some ex-smokers experience increased cravings for fat and sugar as symptoms of nicotine withdrawal. Focusing on healthier snacks can prevent further weight gain.