Cape Town. 120904. Larger than the average persons in Cape Town Cantre. Picture Courtney Africa

Johannesburg - Some obese people are as healthy and fit as those of normal weight – and carry no greater risk of developing heart disease or cancer.

This is one of the findings, published in the European Heart Journal on Tuesday, of the largest study ever to have investigated this subject.

And a second study describes something called the “obesity paradox”: once people have developed heart disease, they are less likely to die if they are overweight or obese, while the underweight or normal weight patients have an increased risk of dying.

In the first study, the researchers from the University of Granada, the Karolina Institute in Sweden and the University of South Carolina in the US found that there is a subset of obese people who are metabolically healthy: they do not suffer from diabetes, high cholesterol or high blood pressure.

Lead author Francisco Ortega said in a statement released by EurekAlert! that it was well known that obesity was linked to a large number of chronic diseases like heart disease and cancer.

“However, there appears to be a subset of obese people who seem to be protected from obesity-related metabolic complications,” he said.

The research looked at 43 265 people, who were recruited from the Aerobics Centre Longitudinal Study in the US between 1979 and 2003.

The study showed that the difference between this healthy obese subset and other obese individuals was that the subset had better levels of cardio-vascular fitness – measured by how well their hearts and lungs performed – which was largely from getting more exercise.

Ortega said their study suggested that those obese people who were metabolically healthy were also those who were fitter than the other obese people.

“We believe getting more exercise positively influences major body systems and organs and contributes to making someone metabolically healthier, including obese people,” Ortega said.

He said the study showed for the first time that metabolically healthy obese people had the same prognosis as those of normal weight.

The second study, about the obesity paradox, analysed data between 2003 and 2008 from 64 000 Swedish patients who had heart disease.

The researchers discovered that the heart patients who were underweight had the greatest risk of dying – double that of normal-weight patients.

Those patients with the lowest risk of death were the overweight and obese patients.

The researchers say it is well known that maintaining a healthy weight is one way to avoid developing heart problems. But once overweight or obese people had developed heart disease, there was no evidence that proved their losing weight would help their heart problems.

Oskar Angeras from the University of Gothenburg said: “Actually, some evidence suggests that weight loss after acute coronary syndromes might in fact have a negative effect.” - The Star