A special commission in The Lancet Diabetes & Endocrinology has published a groundbreaking report aimed at redefining obesity and its diagnostic criteria. Currently, body mass index (BMI) is widely used to diagnose obesity. However, BMI has significant limitations, as it does not take into account the actual distribution and impact of body fat on health.
Why rethink the definition of obesity?
Obesity affects almost one eighth of the world's population, but its definition remains vague and simplistic. BMI, while useful for large-scale epidemiological studies, is ill-suited to an accurate assessment of individual risk. For example, a person with a high BMI may be in good health, while another with a lower BMI may present significant risks linked to excess abdominal fat.
Clinical vs. preclinical obesity
The Commission introduces two key concepts:
Clinical obesity: Considered a chronic disease, it manifests itself as organ dysfunction caused directly by excess fat. Its consequences can include serious illnesses such as heart attacks, strokes and kidney failure. Diagnosis is based on clinical signs such as limitations in daily activities and medical test results demonstrating organ damage.
Pre-clinical obesity: refers to excess body fat with no apparent organ dysfunction, but with an increased risk of developing chronic diseases in the future. The aim is to identify these at-risk individuals early so as to prevent progression to clinical obesity through targeted interventions and regular follow-up.
This distinction makes it possible to adapt management strategies: preclinical obesity would mainly require health advice and follow-up, while clinical obesity might require more intensive treatment, such as medication or surgery.
New methods for diagnosing obesity
The Commission recommends the use of more precise indicators than BMI alone, such as :
Waist circumference and waist-to-hip ratio to better assess cardiovascular risk.
Direct analysis of body fat (using DEXA or impedancemetry) for a more detailed assessment.
These methods aim to identify at-risk individuals more effectively, and propose personalized prevention and treatment strategies.
A call to action for political decision-makers
The Commission underlines the urgent need to reform public health policies to better respond to the challenges posed by obesity. It stresses the importance of guaranteeing equitable access to evidence-based care, irrespective of individuals' economic resources. In addition, combating weight-related stigma is essential to improving the effectiveness of treatment. Healthcare professionals should be better trained to deal with obesity without prejudice, and to offer respectful and appropriate support.
Why this new definition is important
This new approach could profoundly transform the way obesity is perceived and treated. Early identification of those at risk would help prevent serious complications and direct patients towards more targeted, personalized interventions. By recognizing clinical obesity as a genuine chronic disease, it would become easier to obtain funding and resources for appropriate treatments, while avoiding simplistic diagnoses and inadequate care based solely on BMI.
Changing our vision of obesity for a healthier future
The new definition of obesity proposed by the Commission offers a more nuanced perspective, adapted to clinical realities. By distinguishing clinical obesity from preclinical obesity, it enables more targeted and fairer treatment. This approach could also help reduce the stigma associated with obesity, and better guide public health policies. If these recommendations are adopted, they could improve the quality of life of those concerned, while optimizing the allocation of medical resources.