Beyond BMI: Practical Guide for Clinicians to Integrate the Lancet Commission's Obesity Framework and King's Obesity Staging System.

Body mass index (BMI) on its own is a poor diagnostic and staging tool for obesity because it does not measure health status. The newly published Lancet Clinical Obesity Criteria (LCOC) for defining clinical obesity distinguish preclinical and clinical obesity based on organ or tissue dysfunction. The King's Obesity Staging System (KOSS) goes further and incorporates biomedical, psychosocial, and economic factors while offering a practical, holistic, and health domain-specific assessment of obesity's impact. This paper compares and maps the LCOC against the KOSS to highlight their complementary aspects, strengths, and potential for integration. By combining the LCOC philosophical framework with the practical patient-centred approach of the KOSS, we propose a unified model that enhances diagnostic ability and allows the clinician to track the impact of any obesity treatment. This integrated framework advances obesity management, addressing both medical, functional, and broader psychosocial challenges.