Clinical Assessment of Obesity Beyond Body Mass Index: Adiposity Evaluation, Body-Composition Phenotyping and Disease Staging: A Narrative Review

Obesity is usually classified or assessed using the body mass index (BMI), mainly because BMI is simple and easy to apply. Its simplicity is also its main weakness. BMI does not measure fat mass, fat-free mass, or fat distribution. This is a relevant limitation, since individuals with the same BMI may have different amounts of visceral adipose tissue and different cardiometabolic risks. Recent recommendations from the Commission on Clinical Obesity also emphasize that BMI should be used mainly as a screening tool, while excess adiposity should be confirmed using additional anthropometric or body composition measures. This narrative review examines clinical methods for obesity assessment beyond BMI and discusses their practical value in routine care. A literature search was performed in PubMed and Google Scholar for articles published up to August 2026. Guidelines, consensus statements, reviews, meta-analyses, and original studies were considered. The review focused on anthropometric indices, body composition techniques, and imaging-based methods used to assess adiposity, fat distribution, and obesity-related risk. The reviewed evidence supports a complementary approach. Anthropometric indices help evaluate abdominal adiposity and cardiometabolic risk. Body composition methods add information on fat mass, fat-free mass, and regional distribution. Imaging techniques offer the most detailed assessment of visceral, subcutaneous, and ectopic fat, although their routine use is limited by cost, availability, technical requirements, or radiation exposure. BMI remains useful for initial screening, but it is not sufficient for a complete obesity assessment. Combining anthropometric, body composition, and imaging-based methods may improve the evaluation of excess adiposity, fat distribution, and clinical risk.