Despite the findings in this study, well-known factors that contribute to obesity -- such as caloric intake and lack of physical activity -- are probably at the root of the problem, experts said.
Also, environmental causes have made it easier for people to have more sedentary lifestyles, said Keith-Thomas Ayoob, associate professor in the Department of Pediatrics at Albert Einstein College of Medicine.
"Restoring a more active lifestyle throughout the life cycle is critical to managing weight, not question about it," Ayoob said.
When Littman, the former smoker, made his final attempt to stop smoking, he first lost about 35 pounds while he still smoked and then quit smoking.
This way, he did not replace one craving with another because he lost weight first and then focused on maintaining a healthy lifestyle, he said.