Do We Need Body Composition Analysis in Patients with Obesity? A Rethinking of Body Composition Assessment in...

Recent consensus statements from the European Association for the Study of Obesity and the 2024 Lancet Obesity Commission have renewed the debate on how obesity should be defined and clinically characterized. Although both frameworks acknowledge the limitations of body mass index (BMI), they continue to rely largely on anthropometric measures such as BMI and waist circumference for diagnosis and risk stratification. In these definitions, body composition analysis (BCA) received comparatively little attention. However, obesity represents a heterogeneous condition characterized not only by excess adiposity but also by alterations in fat distribution, ectopic fat accumulation, and skeletal muscle mass. Advances in imaging and body composition methodology now allow a more detailed characterization of these components and their metabolic consequences. In this perspective, we examine the potential role of BCA in the assessment of preclinical and clinical obesity. Rather than focusing on what can technically be measured, we address the clinically relevant question of what should be measured and in which patients. Specifically, we discuss whether measures of fat mass should replace BMI for diagnosing obesity, whether visceral adipose tissue should replace waist circumference for cardiometabolic risk assessment, whether liver fat should be routinely assessed, and whether skeletal muscle mass should be evaluated in clinical practice. We conclude that BCA provides clinically relevant information that complements traditional anthropometric measures. When applied selectively, it may improve risk stratification, help monitor treatment responses, and support individualized management strategies in patients with obesity.