Beyond BMI: We are discussing a new concept for the definition and diagnosis of clinical obesity

Obesity is a serious threat to public health worldwide. Being an integral component of the unfavorable cardiometabolic continuum, obesity is mainly considered as a risk factor for the development of a number of non-communicable diseases. At the same time, according to current approaches to its definition, obesity is an independent disease that leads to a deterioration in human health. In this regard, the growing burden of obesity, which is closely associated with an increased risk of developing a number of non-communicable diseases, such as cardiovascular diseases, type 2 diabetes mellitus, chronic kidney disease, metabolic-associated fatty liver disease, and diseases of the musculoskeletal system, dictates the need to revise established views on this complex problem. In January 2025, a new concept “Definition and diagnostic criteria of clinical obesity” was presented, developed by a Lancet journal commission consisting of 56 leading clinical experts. The authors call for a “rethink of the understanding of obesity, arguing both for and against the current definition of obesity. A division into preclinical and clinical obesity is proposed, taking into account the organ dysfunction caused by overweight. The definition of clinical obesity, according to the authors, fills an important conceptual gap in the concept of obesity, since it provides clinical identity to the characteristic changes in organ function directly caused by overweight, regardless of other diseases associated with it. This rethinking provides a meaningful medical mechanism for informing diagnosis, clinical decision-making, and management decisions in healthcare. This article provides an overview of the basic information about current approaches to the diagnosis of obesity and the principles of a new concept for the definition and staging of obesity.