Beyond BMI: A new framework for diagnosing obesity with a focus on overall health

The traditional method of diagnosing and managing obesity, which heavily relies on body mass index (BMI), is increasingly seen as inadequate. Acknowledging this, the European Association for the Study of Obesity (EASO) has introduced a comprehensive new framework for diagnosing, staging, and managing adult obesity. Detailed in a recent publication in Nature Medicine, this framework aims to incorporate the latest scientific insights and advancements, including novel obesity medications, to ensure more effective and inclusive treatment strategies.

Obesity is widely recognised as a multifactorial, chronic, relapsing, non-communicable disease characterised by an abnormal and/or excessive accumulation of body fat. Traditionally, the diagnosis has been predominantly based on BMI cut-off values. This method fails to consider critical factors such as the distribution and functional roles of adipose tissue in the disease’s severity.

The EASO Steering Group, comprising current and former association presidents among other experts, has crafted a series of statements that update the obesity management approach to reflect the latest scientific knowledge. A key update in this new framework is the revised approach to the anthropometric component of obesity diagnosis. The authors explain, “An important novelty of our framework regards the anthropometric component of the diagnosis. The basis for this change is the recognition that BMI alone is insufficient as a diagnostic criterion, and that body fat distribution has a substantial effect on health.” They specifically highlight the health risks associated with the accumulation of abdominal fat, noting its association with an increased risk of cardiometabolic complications and its significance as a determinant of disease, even in individuals with a BMI below traditional obesity thresholds.

The new framework underscores the importance of considering abdominal (visceral) fat accumulation as a critical health risk factor, even in individuals with lower BMI (≥25–30 kg/m^2) who exhibit significant abdominal fat but may lack overt clinical symptoms. This broader definition aims to reduce the risk of undertreating these individuals compared to the current BMI-based criteria.

Treatment recommendations within the framework align with existing guidelines but emphasise behavioural changes such as dietary adjustments, increased physical activity, stress management, and improved sleep quality. Psychological therapy, obesity medications, and metabolic or bariatric procedures are also considered crucial, depending on individual needs.

The steering committee has pointed out that the traditional reliance on BMI cut-offs in clinical trials and guidelines often excludes individuals who, despite having a lower BMI, carry a significant obesity-related health burden. The committee suggests a shift towards including patients with a BMI of at least 25 kg/m^2 and a waist-to-height ratio above 0.5, who also exhibit medical, functional, or psychological impairments, in obesity medication and treatment programmes.

The authors make a call to action to pharmaceutical companies and regulatory bodies: “This statement may also be seen as a call to pharmacological companies and regulatory authorities to use inclusion criteria that are more adherent to the clinical staging of obesity and less to traditional BMI cut-offs when designing future clinical trials with obesity medications.”

In conclusion, the authors advocate for a paradigm shift in obesity management, likening it to the management of other chronic non-communicable diseases. They emphasise the importance of defining long-term, personalised therapeutic goals from the outset of treatment, considering the disease’s stage and severity, therapeutic options, side effects, patient preferences, and individual challenges. They stress the necessity for a comprehensive, life-long treatment plan over mere short-term weight reduction, stating, “Emphasis on the need for a long-term or life-long comprehensive treatment plan rather than short-term body weight reduction is warranted.”