The researchers looked for buildup of calcium plaque in the heart's arteries, which is an early sign of heart disease. Calcium plaque is linked to atherosclerosis, which is a stiffening and hardening of the arteries.
The investigators found that the obese people had a higher prevalence of atherosclerosis of the heart arteries than the people of normal weight. If atherosclerosis is not managed, it can lead to heart attack and sudden cardiac death, among other heart conditions, the researchers noted.
"Obese individuals who are considered 'healthy' because they don't currently have heart disease risk factors should not be assumed healthy by their doctors," Chang said in a statement.
"Our research shows that the presence of obesity is enough to increase a person's risk of future heart disease and that the disease may already be starting to form in their body. It's important that these people learn this while they still have time to change their diet and exercise habits to prevent a future cardiovascular event," Chang said.
Dr. David Katz, director of the Yale University Prevention Research Center, said these findings are not surprising and expects that the same results would be found among obese Americans.
"There has long been debate about the relative importance to health of fitness versus fatness. The argument has been made that if one is fit, fatness may not be a significant health concern," he said.
While fat and fit is better than fat and unfit, this study adds to a growing body of evidence that challenges that assertion. "Excess body fat can increase inflammation, one of the key factors contributing to heart disease, and other chronic diseases as well," Katz said.
The good news about fitness and fatness is that the same strategies that help people stay fit are the ones that help them lose weight, he said. "Eating well and being active remain the best medicine for both losing excess weight, and staying healthy," Katz noted.