Can you be healthy and overweight?

The research we'll be discussing today really got people's attention: the editor of the Annals of Internal Medicine set the tone by writing an editorial titled "The Myth of Healthy Obesity." It's the secondary results of this study that I find even more interesting, however.

Researchers at the University of Toronto, Canada, analyzed the data from 12 studies that included a total of over 72,000 people and collected such information as Body Mass Index and details of risk factors such as waist circumference, blood sugars, cholesterol scores, and blood pressures (Ann Intern Med 2013;159(11):758-769). Those with one or more risk factor (other than weight) were considered "metabolically unhealthy," while those with no risk factors (other than weight) were considered "metabolically healthy."

When the researchers compared those considered metabolically healthy and of normal weight with those who were metabolically healthy and overweight or those metabolically healthy or obese, they found that over a ten-year period those who were metabolically healthy and obese were 24% more likely to experience a heart attack or stroke or to die of any cause.

It's clear that over the long term, being clinically obese (having a Body Mass Index over 30) puts you at a significantly greater risk of illness and death - and that's the practical definition of "unhealthy."

That said, what the news outlets did not tout with nearly as much glee is the comparison of those who were metabolically healthy and overweight (with a Body Mass Index between 25 and 30) with those who were metabolically healthy and of normal weight: their risk of heart attack or stroke or death from all causes was not increased.

While being obese in and of itself appears to be a risk factor, being overweight is not.

What this means for you

This does not mean that the definition of normal weight has suddenly increased from a Body Mass Index of 18 to 25 into the overweight area of 25 to 30. All this means is that if you are overweight and otherwise healthy, it is even more important for you to exercise and eat healthfully so that you remain metabolically healthy. We do know that losing weight will often help those who are metabolically unhealthy improve their scores in everything from blood sugars to cholesterol, so that doesn't mean you might not need to lose weight. Being metabolically healthy is not a "get out of jail free card" in terms of weight, whether you are obese or just overweight.

First posted: December 11, 2013