Move Over Healthy Obesity, Here Comes Skinny Fat

“Skinny fat” is the latest expression of dissatisfaction with using of BMI, weight, or appearance to judge a person’s health status. People with a supposedly healthy BMI can have visceral fat causing significant metabolic disease.

The scientific term for this concept is normal weight obesity — excess adipose tissue in people with a BMI in the normal range. It’s the flip side of healthy obesity, which is good metabolic health in someone with a high BMI. Taken together, these two phenomena show the flaws in thinking you can assess obesity based only on the numbers from a scale.

The Journal of the American College of Cardiology has just published a review of fitness, fatness, and cardiovascular disease that offers good perspective. Says Tim Church, one of the review’s authors:

Everyone got really fixated on the people who were obese but not metabolically sick due to high fitness levels, but what was lost in the message was that we had plenty of people with a BMI below 25 who were unfit and at a high risk.

A very complete overview of normal weight obesity was just published in Progress in Cardiovascular Diseases. Experts from the Mayo Clinic nicely summarize the rapidly accumulating evidence for metabolic and cardiovascular disease, along with higher mortality in people with normal weight obesity. And they call for defining obesity based on adiposity, not body weight.

So it’s worth remembering what obesity is and what it isn’t. Obesity is a disease of excess adipose tissue. Casual diagnosis based on weight and appearance is not just inappropriate, it’s offensive.

Click here to read more in Time, here to read more in the Journal of the American College of Cardiology, and here to read more in Progress in Cardiovascular Diseases. For a snarky view of the subject, click here to read more from Jezebel.

Compare and Contrast, photograph © an untrained eye / flickr

Subscribe by email to follow the accumulating evidence and observations that shape our view of health, obesity, and policy.