Quitting smoking doesn't mean people will gain large amounts of weight.
Researchers at the University of Otago have found the weight of people who stop smoking returned to the same level as people of a similar age who never smoked in the first place.
The newly published research also shows people who quit only gained a small amount of weight - 5kg - compared with people who carried on smoking.
The findings were the same for men and women.
The findings are part of the Dunedin Multidisciplinary Health and Development Study, which has closely followed the progress of about 1000 people born in Dunedin in 1972-73.
About one third of the group were smokers at age 21, and by age 38 about 40 percent of those people had quit.
