Healthy Obese Phenotype Is a Myth

A new study shows that even healthy obese adults tend to become unhealthy in the long-term, providing further evidence against the idea of healthy obesity.

Researchers at University College London (UCL; United Kingdom) conducted a study to answer a fundamental question: do healthy obese adults maintain this metabolically healthy profile over the long term, or do they naturally suffer transition into unhealthy obesity over time. To do so, they followed 2,521 British government workers (75% male, ages 39–62 years at baseline), of whom more than 180 were obese, with 66 (36.5%) of them classified as healthy obese.

At 5, 10, 15, and 20 years follow-up, 21, 27, 23, and 34 of these individuals remained obese, but had a worsening of their cardiometabolic profile, resulting in more than 51% of previously healthy obese participants deemed unhealthy obese at the 20-year mark. Just six percent of people in the healthy obese group lost weight, and were reclassified as healthy non-obese at the end of the first five years. This percentage rose to 10.6% at 20 years. The study was published in the January 6, 2015, issue of the Journal of the American College of Cardiology.

“Healthy obese adults were nearly eight times more likely to progress to an unhealthy obese state after 20 years than healthy non-obese adults, providing further evidence against the idea that obesity can be healthy,” concluded lead study author Joshua Bell, MSc, and colleagues. “Healthy obesity is only healthy in a relative sense, in that the risk of disease is lower than for unhealthy obese adults, but still higher than for healthy normal-weight adults.”
For the study, metabolically healthy was defined as having less than two of the following risk factors: HDL cholesterol lower than 1.03 mmol/L for men and lower than 1.29 mmol/L for women; blood-pressure higher than 130/85 mmHg or use of antihypertensive medications; fasting plasma glucose levels of over 5.6 mmol/L or use of antidiabetic medications; triglyceride level higher than 1.7 mmol/L; and a homeostatic model assessment (HOMA) of insulin resistance higher than 2.87.

Related Links:
University College London