A Bigger Body Does Not Equal a Diseased Body

Yet another pair of studies is stirring up confusion about whether obesity is defined entirely by a bigger body.

Elisa Fabbrini and colleagues from the Washington University School of Medicine studied the metabolic effects of weight gain in a small, elegant study comparing people with normal metabolic heath at a BMI above 30 with matched controls. People in the control group had measurable metabolic disease. The average BMI for all participants in this study was 36.

What they found was that weight gain caused further metabolic harm in people with metabolic disease. But for the people with good metabolic health despite a high BMI, no metabolic harm occurred. In other words, they found that some people do indeed appear to be resistant to the typical health effects of excess weight. Senior investigator Sam Klein commented:

These results suggest that the ability of body fat to expand and increase in a healthy way may protect some people from the metabolic problems associated with obesity and weight gain. We need more studies to try to understand why obesity causes specific diseases in some people but not in others. Could it be genetics, specific dietary intake, physical lifestyle, emotional health or even the microbes that live in the gut?

As if to counter this controlled study, an observational study published today in the Journal of the American College of Cardiology followed people for 20 years with a BMI over 30 and fewer than two markers of metabolic disease. They found that half of those subjects progressed to have more signs of metabolic disease after 20 years — half did not. The authors go with their gut and conclude that “the natural course of healthy obesity is progression to metabolic deterioration.” So half of the people in this study, those who did not progress, were unnatural?

Headline writers promptly responded with headlines saying “Study Debunks Healthy Obesity.” And thus we have a continuing cycle of bunk in the form of sensational headlines.

The whole debate over “healthy obesity” is a bit tiresome. It’s not typical for someone to have a high BMI and remain healthy, but it happens. If someone is healthy despite a high BMI, they might be big, but they don’t have the disease of obesity. People who want to equate obesity with BMI might as well be equating thirst with diabetes. It’s a good clue, but it’s not a diagnosis. Diagnosis requires more than height and weight or just a glance.

Obesity is an excess of adipose tissue (fat) that interferes with good health. Anyone who argues otherwise is setting up a straw man.

Click here to read more from the LA Times and here to read the study from Fabbrini et al.  Click here to read more from ConscienHealth.

Big Brother, photograph © Thomas Leuthard / flickr

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