从BMI到体脂百分比：精准医疗时代肥胖诊断的重新定义

From BMI to Body Fat Percentage: Redefining Obesity Diagnosis in the Era of Precision Medicine

摘要: 肥胖已成全球重大公共卫生挑战。长期作为核心筛查工具的身体质量指数(BMI)因无法区分脂肪与瘦体重、忽视脂肪分布异质性及存在种族差异，在精准医疗背景下局限性凸显。本综述系统阐述肥胖诊断从“以BMI为中心”向“以体脂为核心”的范式演进，重点解析2025年《柳叶刀》委员会提出的“临床肥胖”新框架——该框架将肥胖界定为脂肪过量直接导致的慢性疾病，区分“临床前肥胖”与“临床肥胖”，推动诊断从“体重评估”转向“脂肪与功能联合评估”。文章评价体脂百分比、腰围、腰高比、相对脂肪质量等替代指标效能，阐明正常体重肥胖等BMI掩盖表型的临床意义，并结合中国人群特征与医疗资源配置现状，提出分层落地路径，为构建适配中国人群的精准肥胖诊断体系提供参考。

Abstract: The global obesity epidemic is a major public health challenge. The long-standing screening tool, Body Mass Index (BMI), is limited in the era of precision medicine due to its inability to distinguish fat from lean mass, ignore fat distribution heterogeneity, and vary across ethnicities. This review outlines the paradigm shift in obesity diagnosis from BMI-centric to adiposity-centered assessment, with a focus on the 2025 Lancet Commission’s novel “clinical obesity” framework. This framework defines obesity as a chronic disease caused by excess adiposity, differentiates between pre-clinical and clinical obesity, and shifts diagnosis from weight-focused to integrated adiposity and functional evaluation. We appraise alternative metrics including body fat percentage, waist circumference, waist-to-height ratio, and relative fat mass, clarify clinical implications of BMI-masked phenotypes such as normal-weight obesity, and propose a tiered implementation pathway tailored to Chinese populations to support precise obesity diagnosis.