Global Experts Call for Overhaul in Obesity Diagnosis Framework

A newly proposed framework could transform how obesity is diagnosed, moving beyond body mass index (BMI) to assess body fat distribution and organ health, according to a Commission published in The Lancet Diabetes & Endocrinology.¹ Endorsed by over 75 medical organizations, the global Commission aims to improve clinical care and challenge misconceptions about obesity as a disease.²

The Commission recommends using additional measures like waist circumference and direct body fat assessment to complement BMI and reduce diagnostic errors. | Image credit: Vitalii Vodolazskyi – stock.adobe.com

Current approaches to diagnosing obesity really heavily on BMI and have faced growing criticism for a number of reasons.¹ While BMI is a simple measure to estimate body fat, it fails to account for fat distribution or individual health differences.

Critics argue that BMI-based definitions of obesity risk overdiagnosis, leading to unnecessary treatments and escalating health care costs, and many individuals with high BMI do not exhibit signs of illness, underscoring the heterogeneity of obesity. For instance, some patients may store excess fat in their waist or around organs like the heart and liver, which poses a higher health risk than when fat is stored just under the skin in the arms or legs.

“But people with excess body fat do not always have a BMI that indicates they are living with obesity, meaning their health problems can go unnoticed,” explained Robert Eckel, MD, professor of physiology and biophysics at the University of Colorado Anschutz Medical Campus, and one of the authors of the Commission.² “Additionally, some people have a high BMI and high body fat but maintain normal organ and body functions, with no signs or symptoms of ongoing illness.”

With over a billion people estimated to be living with obesity around the world, this debate has spurred calls for more nuanced diagnostic tools that consider body composition and organ health rather than relying solely on BMI thresholds.

How Will Obesity Be Measured?

While not replacing BMI itself, the Commission recommends using additional measures like waist circumference and direct body fat assessment to complement BMI and reduce diagnostic errors.

It introduces 2 new diagnostic categories: clinical obesity, which is characterized by chronic disease with organ dysfunction due to excess fat, and pre-clinical obesity, where organ function remains intact but long-term health risks—such as for diabetes and cardiovascular disease—are elevated. This will help drive more personalized care, where individuals with pre-clinical obesity may benefit from risk-reduction strategies like counseling or lifestyle interventions, while those with clinical obesity require more aggressive management to restore organ function.

“This includes timely access to evidence-based treatments for individuals with clinical obesity, as appropriate for people suffering from a chronic disease, as well as risk-reduction management strategies for those with pre-clinical obesity, who have an increased health risk, but no ongoing illness,” said Francesco Rubino, MD, professor and chair of metabolic and bariatric surgery at King's College London, and one of the Commission authors. “This will facilitate a rational allocation of healthcare resources and a fair and medically meaningful prioritisation of available treatment options.”

These personalized treatment plans also prioritize restoring the patient’s health rather than focusing solely on weight loss. By distinguishing between clinical and pre-clinical obesity, the new model allows for more efficient allocation of health care resources and ensures patients receive the care that is tailored to their specific needs. The report also highlights the stigma associated with obesity, which the new framework aims to reduce by promoting respect and clarity in clinical care.

How Would This Impact Insurance?

The report authors also urged health insurers to cover obesity treatment as a standalone condition without requiring comorbidities like type 2 diabetes, stating that clinical obesity should not necessitate another disease to justify coverage.¹

They also called for insurers to provide comprehensive coverage for evidence-based treatments for those with clinical obesity—recognizing it as a chronic and potentially life-threatening illness—as well as counseling, screening, and monitoring for those with preclinical obesity to reduce the risk of developing clinical obesity and related diseases.

Under this framework, professional organizations and academic institutions should also prioritize education initiatives that equip health care providers with the tools to implement clinical obesity diagnostic criteria in practice. Addressing weight bias and enhancing understanding of the modern science of obesity are also key components. For public health, strategies should be rooted in scientific evidence rather than blaming individual responsibility, fostering a balanced approach between prevention and treatment for more efficient resource allocation.

By embracing a more nuanced diagnostic approach, the Commission sets the stage for improving patient outcomes while reducing the stigma and oversimplification that have long hindered progress in obesity management.

“Although a blanket consideration of obesity as a disease can raise legitimate concerns about the risk of overdiagnosis, with detrimental consequences on both individuals and society, clinical obesity objectively reflects ongoing illness, therefore providing a rational and medically meaningful target for diagnosis and treatment prioritization,” the Commission said. “It is our hope that such reframing can inform public health policies, facilitate identification of appropriate targets for prevention versus treatment strategies, and contribute to overcoming misconceptions that reinforce weight-based bias and stigma.”

References

1. Rubino F, Cummings DE, Eckel RH, et al. Definition and diagnostic criteria of clinical obesity. Lancet Diabetes Endocrinol. Published online January 14, 2025. doi:10.1016/ S2213-8587(24)00316-4
2. The Lancet Diabetes & Endocrinology: global commission proposes major overhaul of obesity diagnosis, going beyond BMI to define when obesity is a disease. News release. The Lancet. January 14, 2025. Accessed January 14, 2025. https://www.eurekalert.org/news-releases/1069985