Those who quit smoking return to their natural weight – University of Copenhagen

Health > News > Smoking

29 December 2015

Those who quit smoking return to their natural weight


New Danish research from the University of Copenhagen clean-out the many myths regarding weight gain after smoking cessation. Those who quit smoking end up weighing the same as comparable never-smokers. According to the researcher behind the study, the finding may very useful when doctors give advice on smoking cessation.

"I would like to quit smoking, but I'm afraid to gain 10 kg."

There are many excuses for not quitting smoking and the fear of weight gain is one of them. Now a new study provides clear answers: Those who quit smoking will reach their natural weight, defined as their weight had they never smoked.  The study has just been published in Preventive Medicine, and was carried out by researchers and medical doctors from the Research Unit for General Practice at the University of Copenhagen and Clinical Institute at the University of Southern Denmark.

"Smokers weigh less than non-smokers, because nicotine reduces your appetite and increases metabolism.  This means that smokers have an artificially low weight, and when they quit smoking, they gain weight. Thanks to the study, we now have a tool we can use when giving advice on smoking cessation in general practice. It may be easier for people to accept a weight gain if they know that it's natural and that they just return to their normal weight," says Rasmus Køster-Rasmussen, medical doctor and PhD.

The study included 1,374 ordinary Danes who had all been registered with the same general practice from 1998-2008. Weight changes have been adjusted for gender, age, BMI, education, physical activity and chronic disease. Thus, the results are representative of the Danish population.

Quit smoking despite the extra kilos
As something completely new, the study focuses on how smokers' weight develops when they quit smoking compared to the normal weight development of never-smokers. On average, ordinary people gain weight through adult life until the age of 60, after which the weight begins to drop. After nine years, the average weight gain as a result of quitting smoking was 3.5 kg. The never-smokers had gained 1.8 kg, those who had quit smoking had gained 4.6 kg, while the smokers had gained 1.1 kg.

In spite of the extra kilos gained, it is , however, still a good idea to quit smoking.

 "It's far more unhealthy to smoke than to gain a little extra weight," says Rasmus Køster-Rasmussen.

Read the article Back on track — Smoking cessation and weight changes over 9 years in a community-based cohort study at


Rasmus Køster-Rasmussen, medical doctor and PhD
tel. +45 50 59 98 66