A global panel of 58 experts from diverse medical specialties proposed a transformative framework for understanding and diagnosing obesity, marking a significant shift in how the condition is approached in clinical and public health settings. Their recommendations, developed through consensus and endorsed by 76 global organizations, aim to redefine obesity as a chronic, systemic illness with far-reaching implications for patient care, public health policy, and societal attitudes.
The Commission emphasized that while Body Mass Index (BMI) is a widely used tool, it is limited as a measure of individual health. BMI can misclassify individuals, both underestimating and overestimating adiposity, and provide insufficient information about an individual’s overall health status.
Instead, the group advocates for a more nuanced diagnostic approach that includes direct adiposity measurements with advanced imaging techniques where feasible. Also, anthropometric criteria such as waist circumference, waist-to-hip ratio, or waist-to-height ratio, tailored to an individual’s age, gender, and ethnicity. The use of BMI should be used primarily for population-level screening or epidemiological studies rather than individual diagnosis.
Redefining Obesity: Clinical vs. Preclinical States
The Commission introduced two key definitions.
Clinical Obesity: A chronic illness characterized by structural or functional damage to organs, tissues, or the individual, caused directly by excess adiposity. It can lead to severe complications such as heart attack, stroke, and kidney failure.
Preclinical Obesity: A state of excess adiposity without evident organ dysfunction but with an increased risk of developing clinical obesity and related diseases, including type 2 diabetes and cardiovascular conditions.
Key Characteristics of Clinical Obesity
- An obesity phenotype combined with
- Signs, symptoms, or limitations in daily activities, such as impaired mobility or respiratory function.
Unlike metabolically unhealthy obesity, clinical obesity is not tied exclusively to cardiometabolic risk. For example, musculoskeletal or respiratory issues caused by excess adiposity qualify as clinical obesity even if metabolic function remains normal.
Diagnosing Clinical Obesity
Diagnosis requires both anthropometric and clinical criteria:
- Anthropometric Criterion
- Excess body fat must be confirmed through direct fat measurements (if available) or other validated anthropometric measures like waist circumference, in addition to BMI.
- For individuals with a BMI over 40 kg/m², excess adiposity can be assumed without further confirmation.
- Clinical Criteria (one or both of the following):
- Evidence of dysfunction in organ systems caused by obesity (e.g., respiratory distress, musculoskeletal pain).
- Age-adjusted limitations in daily activities, such as difficulty with bathing, dressing, or mobility.
Key Characteristics of Preclinical Obesity
- Not a pre-disease state: While it may precede clinical obesity in some individuals, it is not universally progressive.
- Not overweight or pre-obesity: Preclinical obesity requires confirmation of obesity-level adiposity and preserved organ function.
- Not metabolically healthy obesity: It encompasses the potential impact of obesity on multiple organs, not just metabolic ones.
Implications of Preclinical Obesity
Individuals with preclinical obesity face variable, but generally increased risk of:
- Developing clinical obesity.
- Acquiring related diseases like type 2 diabetes, cardiovascular conditions, or certain cancers.
Managing Preclinical Obesity
Management includes:
- Screening and monitoring for early signs of clinical obesity or related diseases.
- Targeted interventions for individuals at high risk to prevent progression or facilitate treatment of other conditions, such as orthopedic or cancer therapies.
Recommendations for Care and Policy
The report underscores the importance of timely, evidence-based treatment for people with clinical obesity, aiming to mitigate or reverse its effects and prevent further complications, noted the Commission in The Lancet. Those with preclinical obesity should receive health counseling, regular monitoring, and interventions to lower the risk of progression to clinical obesity.
Additionally, the Commission called for equitable access to obesity treatments as part of chronic disease care. Also, public health strategies should be informed by scientific evidence, rather than outdated assumptions about individual responsibility for obesity. Training should be provided for health care professionals and policymakers to combat weight-based stigma, a significant barrier to effective care.
Recognizing obesity as a chronic disease has been a topic of intense debate. Critics argue that defining obesity as a disease may shift focus away from individual responsibility and lead to overdiagnosis or unnecessary treatments. Supporters counter that this recognition is essential to reduce stigma, improve access to care, and acknowledge the complex, multifactorial nature of obesity.
This framework offers clinicians a path to more personalized, effective care. By moving beyond BMI and focusing on measurable health outcomes, physicians can better address the needs of patients with obesity while reducing stigma and improving overall health outcomes.
