Teenage girls who smoke more than double their chance of becoming obese in adulthood, according to a study hailed by Australia's Quit organisation as a myth-buster.
The research also found girls who smoked more than 10 cigarettes a day in their teens went on to have waists measuring about 3.5cm larger than non-smokers when they reached their 20s.
Victoria-based Quit Support Programs manager Luke Atkin said the finding was important as many young women still drew a favourable association between smoking and thinness - despite the dire health warnings.
"This study shows smoking as a teen could actually increase your chances of obesity when you are in your 20s," Atkin said.
"For decades the tobacco industry has pushed the idea that smoking somehow equates to being fashionable or glamorous but as this study shows, a teen girl who smokes could be on a fast track to obesity.
"We welcome findings like these, that potentially turn young people off cigarettes and dismantle any myths around perceived benefits of smoking."
The Finland-based study took in twins born between 1975 and 1979, and they were each mailed a questionnaire after they turned 16.
Researchers collected more data from the group of more than 4,300 young men and women when they hit their 20s, and the results are published in the American Journal of Public Health.
The research found that young women who smoked were twice as likely to become overweight compared to non-smokers in their early 20s, and teenage girls who smoked more than 10 cigarettes a day were at greatest risk, particularly for abdominal obesity.
Atkin also said many smokers continued to put off quitting out a fear they would put on weight.
"It is important for these people to remember that remaining a smoker is more of a health risk than almost anything else," he said.
"Incorporating regular exercise and sensible eating into your daily lifestyle while you are quitting is a good way to ensure that weight gain is not an issue."
About 19% of the Australian population are smokers, down from 34% in 1980.
