A proposed shift in how obesity is defined is creating tension in the medical community
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The framework requires complex measurements and diagnostic evaluations that may not be feasible in many clinical settings and could exacerbate existing health inequities.
—The Endocrine Society
A proposed shift in how obesity is defined is creating tension across endocrinology.
The introduction of “preclinical obesity” aims to refine diagnosis, but critics argue it risks delaying care and complicating treatment decisions.
The current debate centers on a framework proposed by the global Lancet Diabetes & Endocrinology Commission. [] The model moves beyond BMI and introduces two categories: clinical obesity and preclinical obesity.
Clinical obesity requires evidence of organ dysfunction. Preclinical obesity identifies excess body fat without current disease, but with elevated risk. []
This approach reflects longstanding criticism of BMI. The metric fails to distinguish fat from lean mass and ignores fat distribution. The new framework incorporates waist circumference, waist-to-hip ratio, and direct measures of adiposity to improve diagnostic precision. []
Controversies of this proposed shift
The implications are substantial. A large population-based analysis found that applying the new criteria reclassifies a significant proportion of patients. In one dataset, clinical obesity prevalence reached 36%, while preclinical obesity accounted for 7.6% of adults. []
The distinction introduces a disease continuum. Patients with preclinical obesity may have excess adiposity and measurable risk, but no established organ damage. This creates a gray zone in clinical decision-making.
That gray zone is where the controversy begins.
The Endocrine Society has raised concerns about real-world implementation. In a public statement, the society warned that the framework’s reliance on proving organ dysfunction is “difficult to implement in routine clinical care” and “may delay treatment or create barriers to access.” []
Critics also point to inconsistencies in disease classification. Excluding type 2 diabetes as a defining feature of clinical obesity has drawn particular scrutiny.
Francesco Rubino, MD, lead author of the Lancet Commission, pushed back on that criticism. [] “Diseases are defined to identify discrete entities,” he said in an interview with Stat News. “They do not incorporate other independent diseases as their own diagnostic criteria.”
Is this a practice-changing shift?
At the same time, critics warn that the model may introduce new inequities. “The framework requires complex measurements and diagnostic evaluations that may not be feasible in many clinical settings and could exacerbate existing health inequities,” said The Endocrine Society in a press release. []
There are also implications for treatment eligibility. Pharmacologic therapies such as GLP-1 receptor agonists are often tied to diagnostic criteria. A shift toward requiring evidence of organ dysfunction could restrict access for patients currently treated based on BMI alone.
The challenge is operationalizing that model in clinical practice.
Holly Russell, MD, a family-medicine physician at the University of Rochester Medical Center, said, “The reason we keep using [BMI] is because it’s simple and it’s everywhere.” []
For now, BMI remains embedded in guidelines, insurance coverage, and clinical workflows. The proposed definitions have not been universally adopted.
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