A Study to Change the Way We Think About Obesity?

Researchers at York are telling us they have a breakthrough that will change the way we think about obesity. At least that’s what their press release says. And it worked. They made us click the link.

Jennifer Kuk and colleagues found that about one in 20 (5%) of people with a BMI over 30 have no other metabolic abnormalities. So they define those people as having metabolically healthy obesity (MHO). And further, they find that people who fit their definition of MHO have no greater risk for an early death than people with a lower BMI.

Not Exactly a New Concept

Honestly, this didn’t seem like a big revelation to us. As we have written many times before, BMI is a great screening tool for obesity. It’s a good tool for population studies. However, it does not define obesity for an individual. And the literature about MHO is quite extensive.

But the York PR machine worked well and generated quite a few sensational headlines. Some of the headlines talk about busting myths about obesity. So we sought further perspective from David Allison, Dean of the Indiana University School of Public Health. He confirmed our suspicion that this finding is not especially new:

This idea has been the subject of discussion for some time. For example, the classic 1987 paper by Manson et al explored it in JAMA, under the heading “Inappropriate Control of Effects of Obesity.”

Muddying the Waters

This study does one thing quite well. It serves to help folks muddy the waters if they want to pursue an argument that obesity is not a medical concern per se. The straw man argument goes as follows. A BMI of 30 or more defines obesity. But you can have a BMI over 30 and be perfectly healthy. So obesity is not a medical problem.

It’s a false argument because BMI is a screen for obesity, not a clinical definition. The real definition is excess adiposity that impairs health. Look it up on the WHO website. Or the World Obesity Federation describes the facts pretty well:

While BMI is a simple measure that is very useful for populations, it should be considered a rough guide for predicting risk in individuals.

Kuk’s data is interesting. But we wish she would have provided a fuller description of the population with a BMI over 30 and good metabolic health. Deeper insights on such individuals would have been far more useful than another sensational press release.

Click here for the study and here for the press release. For distinctly different findings from a recent study, click here.

Changing Colors, photograph © Peter Nijenhuis / flickr

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July 16, 2018