"Our findings suggest that if a patient is overweight or obese, all efforts should be made to help them get back to a healthy weight, regardless of other factors," said study co-author Camille Lassale, from Imperial College London's School of Public Health.
"Even if their blood pressure, blood sugar and cholesterol appear within the normal range, excess weight is still a risk factor," Lassale said in a university news release. In fact, the increased risk of developing heart disease was more than 25 percent, the study found.
The study used statistics about the health of people in 10 European countries. Researchers focused on weight and signs of heart disease, when blood vessels become clogged.
The authors looked at more than 7,600 people who had cardiovascular events such as death from heart attack, and compared them to 10,000 people who didn't have heart problems.
After adjusting their figures so they wouldn't be thrown off by other lifestyle factors, the researchers found that people with three or more heart risk factors like high blood pressure, high cholesterol or large waist sizes (more than 37 inches for men and 31 inches for women) were more than twice as likely to have heart disease, regardless of whether their weight was normal or above normal.
But those who were considered overweight yet healthy were still 26 percent more likely to develop heart disease than their normal-weight peers. Those considered healthy but obese had a 28 percent higher risk, the study found.
The findings, which don't prove that extra weight causes heart risks to rise, were published Aug. 14 in the European Heart Journal.
"I think there is no longer this concept of healthy obese," said study co-author Ioanna Tzoulaki, a senior lecturer in epidemiology at the university.
"If anything, our study shows that people with excess weight who might be classed as 'healthy' haven't yet developed an unhealthy metabolic profile. That comes later in the timeline, then they have an event, such as a heart attack," she said.