The Unfinished Work on a Clinical Definition for Obesity

The magical Mirror of Erised can drive people mad by showing them their deepest desires. Judging by the flood of papers in recent days, it seems that one such desire is to find consensus for a clinical definition of obesity.

In the past week alone, three such publications have crossed our screens. In the past month, the count approaches a dozen. What makes this subject so maddeningly hard?

Defining and Staging

One of the growing collection of papers on this topic appeared in Preventing Chronic Disease last week. Sohail Zahid and colleagues from Johns Hopkins explored the possibility of building upon the work of the Lancet Commission for defining clinical obesity with a clinical staging system. They focused on the Edmonton Obesity Staging System. They explain that, by itself, the work of the Lancet Commission will not resolve the issues with a clinical definition for obesity:

“The Lancet Commission issued a new framework for obesity, stratifying people into preclinical and clinical groups, depending on the presence of physical limitation and organ damage. Although this definition more comprehensively defines obesity, staging systems can serve as an adjunct to improve risk stratification and allocate limited clinical resources. We recommend further investigation with updated guidelines, clinical integration, and medical education to assess whether these new obesity definitions and schema can improve our management of this challenging public health epidemic.”

However, we could not help but notice an inconsistency in their understanding of the commission’s definition for obesity. You’ll find it in their figure illustrating how Lancet defines clinical obesity. They posit a BMI of 27, waist circumference of 36, and diabetes would mean a person has clinical obesity.

It does not. Diabetes is not a diagnostic criterion for clinical obesity, says the lead author of the commission report, Francesco Rubino. Not unless it’s part of a cluster of metabolic dysfunction.

Persistent Confusion

Rubino expresses frustration with persistent confusion on this point:

“The ‘diabetes issue’ that is so much debated in comments about the commission reflects a misunderstanding of the framework’s intent as a diagnosis and its mistaken interpretation under the lens of a management framework.”

Perhaps it is true that some people misunderstand this framework. This suggests that more work will be necessary to build consensus around the clinical definition for obesity. Recognizing the need for this work seems important.

For recent papers on this subject, starting with the paper by Zahid et al, click here, here, here, and here.

Mirror of Erised, photograph by HarshLight, licensed under CC BY 2.0

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September 3, 2025