Fear of piling on the pounds stops many people from quitting smoking.
But now scientists have found a silver lining. Even if a person does become a little heavier after kicking the habit, the extra weight won't decrease their life expectancy, a study found.
Japanese researchers found people who quit smoking didn't face an increased risk of dying if they gained weight afterwards.
People who gained more than 2kg (4lbs 6 ounces) after quitting smoking still had a 26 per cent lower risk of death compared to smokers, they found.
'Quitters had a significantly lower risk of death compared to smokers regardless of their weight change after they stopped smoking,' said Dr Hisako Tsuji, of the Health Promotion Department in Moriguchi City, Japan, and lead author of the study.
The news comes after decades of research showing smokers tend to be a bit thinner than non-smokers.
Scientists believe nicotine speeds up the metabolism, burning calories at a faster rate.
It also suppresses the appetite by affecting cells in the hypothalamus, the part of the brain responsible for feelings of hunger.
The average person puts on up to two stone (around 13kg) a year after quitting, according to a U.S. study published in May.
When a person quites smoking, thier appetite and sense of taste sometimes improves, tempting them to
HOW SECONDHAND SMOKE CAN MAKE THE PEOPLE AROUND YOU FAT
Some people swear that smoking cigarettes keeps them slim.
But being exposed to cigarette smoke can actually make people pile on the pounds, a study found.
And it is innocent victims of secondhand cigarette smoke are the most likely to gain weight.
'For people who are in a home with a smoker, particularly children, the increased risk of cardiovascular or metabolic problems is massive,' said lead author Professor Benjamin Bikman, of Brigham Young University in Utah.
Passive smoking damages the body because second-hand smoke contains more than 4,000 chemicals, many of which are irritants and toxins, and some of which are known to cause cancer.
Food also acts as a substitute for cigarettes, providing the 'high' formerly felt after smoking.
It can also keep the hands busy, as many ex-smokers find they miss the physical process of rolling or lighting and smoking a cigarette.
As a result, some smokers admitted they continued smoking just to avoid gaining weight.
As part of today's study, researchers compared the deaths of 1,305 Japanese adults who quit smoking with the deaths of 2,803 Japanese smokers.
Participants in both groups were 65 per cent men with an average age 54.
They based their findings on check-ups and follow-ups in 1997 to 2013 at the Health Examination Center of Moriguchi City in Osaka, Japan.
They split the people who had quit smoking into three groups: 362 people who did not gain weight after stopping smoking; 458 who gained no more than 2kg (4lbs 6 ounces); and 485 who gained more than 2kg.
Compared to smokers' deaths, quitters who gained no weight had a 34 per cent lower risk of dying.
Those who gained no more than 2kg had a 49 per cent lower risk of death; and those who gained more than 2kg had a 26 per cent lower risk of death.
As part of the study the figures were adjusted to account for for age, gender, hypertension, diabetes, and hyperlipidemia – a disease characterised by high levels of fats in the blood.
The research was presented at the American Heart Association's Scientific Sessions 2014.
