Healthy obesity refers to those people who are obese, but still have a healthy metabolic profile.Reuters

Obesity can never be healthy and the concept of having a "healthy obesity" is a myth, latest research suggests.

A study published in the Journal of the American College of Cardiology found that the so-called healthy obesity can slowly turn unhealthy over time.

Having a body mass index (BMI) of 19 to 25 is considered ideal, while a BMI above 25 and 30 is taken to be overweight and obese.

Healthy obesity refers to people who are obese, but still have a healthy metabolic profile.

The study looked at 2,521 people, mostly men (75 percent), aged between 39 and 62. Participants underwent tests that measured their cholesterol levels, blood pressure, fasting glucose, triglycerides (a kind of fat found in blood) and insulin resistance. Classification into healthy - unhealthy obese and healthy non obese groups, were based on the test results and on the fact whether the participants were on an antidiabetic medication.

Of the total, 66 were included in the healthy obese category.

Researchers from the University College London, UK, who tracked the participants found that about one-half of the healthy obese people had become unhealthy obese during a course of two decades.

The results showed that healthy obesity is just a myth that does not last long. The authors, while concluding their study, wrote that healthy obese people carried eight times higher risk of becoming unhealthy obese than healthy people who were never obese.

Moreover, healthy obese people are more likely to develop cardiovascular diseases than healthy, non-obese people, according to the authors. However, their risk is much lower when compared to people who are unhealthy obese.

"Healthy obesity is only a state of relative health - it's just less unhealthy than the worst-case scenario. And as we now see, healthy obese adults tend to become unhealthy obese over time, providing further evidence against the idea that obesity can be healthy," the authors wrote, according to CTV Canada am.

"Healthy obesity is only valid if it is stable over time, and our results indicate that it is often just a phase. All types of obesity warrant treatment, even those which appear to be healthy," the authors concluded.

The findings are of concern as nearly 2.1 billion people in the world are obese.

Obesity has been known to invite many health problems including dementia, ovarian cancer, hearing loss and early death. Experts from CDC have added stroke, hypertension, type 2 diabetes, sleep apnea, heart disease, infertility, liver and gallbladder disease into the list.