Former smokers 'gain up to 5kg'
Former smokers gain four to five kilos in weight after they kick the habit, research suggests.
Researchers, based in the UK and France, found that former smokers gained an average of 4.67kg in the 12 months after they quit.
Most of the excess weight is gained during the first three months, they found.
Analysing the results from 62 studies, the authors discovered that in the first three months after giving up, former smokers gain an average of 2.85kg.
However, researchers found a large variation in weight change, with 13% of people gaining more than 10kg and 16% losing some weight.
The study, published on bmj.com, is accompanied by an editorial which suggests that health benefits from quitting outweigh the excess weight gain.
Esteve Fernandez, associate professor of epidemiology at the University of Barcelona, and Simon Chapman, professor of public health at the University of Sydney, said: "The relative long-term health effects of weight gain and smoking cessation also need to be considered with respect to the ultimate public health message that we should derive from this and future studies.
"Although obesity is positively associated with an increased risk of all-cause mortality, cohort studies indicate that modest weight gain does not increase the risk of death; smoking does."