Ideas about “healthy obesity” took a body blow recently with a University of London report that demonstrates an apparent state of good health among obese individuals does not last over time. The report is based on a study of more than 2,500 individuals whose weight and health measures were tracked for a 20-year period.

The report is said to be the longest of its kind, and its findings appear in the Journal of the American College of Cardiology (JACC). The study defined the parameters of “healthy obesity as an absence of high blood pressure, high cholesterol, diabetes, and certain additional metabolic risk factors.

“A core assumption of healthy obesity has been that it is stable over time, but we can now see that healthy obese adults tend to become unhealthy obese in the long term, with about half making this transition over 20 years in our study,” says Joshua Bell, who led the study.

“Healthy obesity is a high-risk state with serious implications for disease risk,” Bell adds.

According to the findings, roughly 50% of the individuals originally classified as “healthy obese” had become unhealthy obese after 20 years. At that same point in the study, only 10% were considered “healthy obese.”

The JACC article describes the primary study sample as adults age 39 years to 62 years, of whom 75% were male.

[Source: Yahoo!, Journal of the American College of Cardiology]