United States Medical Center researched on Smokers, who have quit the smoking. Quitting smoking may lead to some weight gain depend on the individual. To understand personal factors that may contribute to weight gain, the researchers analyzed data from 12 K participants. They looked at the number of cigarettes smoked per day and body mass index before quitting, to see how these factors may have affected weight change over 10 years.

For smokers of fewer than 15 cigarettes per day, there was no significant difference in the 10-year weight gain, between those who quit smoking and those who did not quit. However, for smokers of 25 or more cigarettes per day and those who were obese prior to quitting body mass index of 30 or more the amount of weight gain attributable to quitting was substantial.

Smokers of 25 or more cigarettes per day reported 23 pounds of weight gain that could be attributed to quitting cigarettes and obese smokers reported 16 pounds of weight gain that could be directly attributed to quitting.