Experts urge new perspective on obesity diagnosis and treatment guidelines

U.K. – The traditional method of diagnosing obesity using body mass index (BMI) is inadequate as a marker for health and, consequently, for determining eligibility for weight-loss treatments.

This conclusion is outlined in a report by the Global Commission on Clinical Obesity, published in The Lancet Diabetes and Endocrinology, which advocates for a more comprehensive approach.

The Commission recommends incorporating BMI alongside other measures, such as waist circumference or direct fat measurement, to provide a clearer picture of health risks.

Relying solely on BMI has notable limitations. It fails to identify individuals who store more visceral fat around their organs, which significantly increases their risk of serious health issues compared to those who primarily store fat beneath the skin.

Additionally, individuals with a normal BMI may still have high levels of visceral fat, classifying them as “metabolically obese” but not meeting the current BMI thresholds for intervention.

To address these shortcomings, the Commission suggests a new classification system. People with chronic health problems caused by excess weight would be categorized as having clinical obesity, while those without health issues would fall under preclinical obesity.

This approach seeks to move beyond the polarized debate over whether obesity is a disease.

Professor Francesco Rubino of King’s College London (KCL), chair of the Commission, argues that the binary perspective is flawed, noting that while some individuals with obesity remain healthy long-term, others develop severe illnesses rapidly.

“Considering obesity only as a risk factor, and never a disease, can unfairly deny access to time-sensitive care among people who are experiencing ill health due to obesity alone,” Prof. Rubino explains.

Conversely, “a blanket definition of obesity as a disease can result in overdiagnosis and unwarranted use of medications and surgical procedures, with potential harm to the individual and staggering costs for society.”

The global demand for newer weight-loss medications, such as Novo Nordisk’s Wegovy (semaglutide) and Eli Lilly’s Zepbound (tirzepatide), highlights the urgency of addressing obesity appropriately.

With over a billion people worldwide classified as obese under current definitions, widespread use of these drugs could strain healthcare budgets.

For instance, in the UK, the NHS limits the use of these medications to individuals with a BMI of 30 or higher who also have weight-related conditions like diabetes or cardiovascular disease.

Under the proposed system, treatments such as weight-loss drugs or surgery would be reserved for those with clinical obesity, while individuals with preclinical obesity would receive guidance on weight management and health monitoring.

This personalized care approach, according to Prof. Rubino, would enable “a rational allocation of healthcare resources and a fair and medically meaningful prioritization of available treatment options.”

Prof. Tom Sanders, Emeritus Professor of Nutrition and Dietetics at KCL, supports the recommendations, emphasizing their potential to focus interventions on those who need them most.

He adds that recognizing clinical obesity as a disease could encourage lawmakers to treat it as a disability, addressing discrimination and reducing social stigma.

Prepared by 56 international medical experts and endorsed by over 75 medical organizations globally, the Commission’s report offers a pathway to more effective and equitable obesity care.