Researchers writing in the Journal of the American Medical Association say the prospect of weight gain makes some smokers reluctant to stop.
But they say quitting has a “positive effect on cardiovascular risk.”
The health gains from giving up were most marked in people who did not have diabetes, but people with the condition were still said to have benefitted.
Obesity is a risk factor in heart disease, leading past research to examine whether weight gain might cancel out some of the benefits of quitting smoking.
Studies suggest people who stop smoking gain on average 6-13lb (2.7-5.9kg) over the first six months.
The JAMA research looked at the smoking habits and heart health of more than 3,000 people between 1981 and 2011.
Former smokers who stayed away from tobacco for more than four years had a 54% lower risk of heart and artery disease than smokers.
Recent quitters who had stopped smoking for up to four years experienced almost the same benefit with a 53% lower relative risk.
This was despite recent quitters typically gaining 5-10lb over a period of four years, and long-term quitters 1-2lb.
Dr James Meigs, one of the authors of the study at Harvard Medical School, said: “We can now say without question that stopping smoking has a very positive effect on cardiovascular risk for patients with and without diabetes, even if they experience moderate weight gain.”
Doireann Maddock, senior cardiac nurse at the British Heart Foundation said weight gain should not deter smokers from quitting.
“If you’re keen to quit smoking but worried about putting on weight, using smoking cessation aids such as inhalators, gum, or lozenges may help you resist the temptation to reach for comfort food in the place of a cigarette.”