Some obese people can be just as fit as those of a normal weight and carry no greater risk of developing heart disease or cancer, studies suggest.

Research published in the European Heart Journal Wednesday proposes that a subset of metabolically healthy obese individuals can be physically fit and that increased weight doesn’t seem to have a completely negative effect on their health.

Metabolically healthy individuals do not have problems such as insulin resistance, diabetes or high blood pressure and cholesterol.

"It is well known that obesity is linked to a large number of chronic disease such as cardiovascular problems and cancer, said lead author of the study, Dr. Francisco Ortega, in a press release.

“However, there appears to be a sub-set of obese people who seem to be protected from obesity-related metabolic complications."

Ortega said that these people may have greater cardio-respiratory fitness, which was measured by how well their hearts and lungs performed.

“But, until now, it was not known the extent to which these metabolically healthy but obese people are at lower risk of diseases or premature death,” he said.

The research for one of the studies looked at data from over 43,000 Americans from the Aerobics Centre Longitudinal Study between 1979 and 2003.

Researchers found that being overweight did not have to pose an added health risk, but rather that obese individuals who were metabolically healthy were more fit from getting more exercise, suggesting that the correlation of health to fitness was greater than health to only weight.

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

The study showed that healthy obese people have the same overall prognosis as those in a normal weight range and lower body mass index (BMI).

Obesity paradox

Another study, using data from more than 64,000 patients on the Swedish Coronary Angiography and Angioplasty registry, examined the relationship between obesity and mortality with people suffering with acute coronary syndromes (ACSs).

The study further proved the “obesity paradox,” which suggest that for obese people (with a BMI of less than 40) who also suffer with chronic illness, losing weight is always bad.

The researchers found that underweight heart patients had double the risk of dying than those of normal weight and that overweight and obese patients carried the lowest risk.