The current diagnostic criteria for obesity are based on body mass index (BMI). However, BMI does not directly reflect fat accumulation or its adverse health effects, making it inadequate for clinical needs. In response, the Lancet Diabetes & Endocrinology Commission has proposed a refined definition and diagnostic criteria of obesity, including Pre-clinical Obesity which is defined as having only abnormal anthropometric indicators, thus only lifestyle interventions is recommended to improve body composition and reduce disease risk; as well as Clinical Obesity which is diagnosed when abnormal anthropometric indicators are accompanied by obesity-related comorbidities or limitations in daily activities, necessitating active medical intervention. While several academic societies have raised concerns that this classification may reclassify some obesity cases from a disease state to a risk factor, potentially depriving patients of treatment opportunities, the new criteria overall represents a significant advancement in enabling more precise diagnosis and management of obesity, based on fat accumulation and its impact on organ function.