Heavy smokers are more likely to develop pot bellies, according to a new study which debunked a popular belief that quitting smoking can lead to weight gain.
Researchers from the University of Glasgow conducted a meta-analysis of 29 studies involving almost 150,000 participants containing data on their smoking habits, weight and waist circumference.
While smoking might be associated with lower overall weight it tends to push fat into central areas resulting in a bigger stomach – an unhealthy apple shape, rather than a health pear shape, the study reported.
The analysis found a genetic variation in some smokers associated with an increase in the number of cigarettes consumed and a lower mean body mass index (BMI), thus adding evidence that heavier smoking leads to lower BMI.
But the data, published in the BMJ Open journal, also showed that while overall BMI in heavy smokers was lower, waist circumference was higher than non-smokers once BMI was accounted for.
Smokers who have the variant will consume an extra cigarette a day.
The research suggests that for every copy of the genetic variant associated with increased cigarette consumption, waist circumference increased by 0.14 per cent if BMI were to remain constant.
The result suggests a preferential redistribution of fat towards the stomach.
Professor Naveed Sattar, of the Institute of Cardiovascular and Medical Sciences who co-led the study, said: “One barrier to smoking cessation is the fear of weight gain and whilst smoking lessens weight overall, it tends to push fat more into the central area so waist circumference is preferentially higher.”
“So, when smoker put on weight, they will show bigger tummies for same weight gain than non-smokers and this may also be linked to their greater risk for diabetes,” Sattar said.
On the whole weight goes down in smokers. That’s true at point of smoking, but it means smoking is lessening the chance of putting fat on in the safe bits, he said.