测量BMI
BMI 是诊断肥胖的最常见方法，定义为体重除以身高的平方（[ 体重 (kg)]/[ 身高 (m)]^2）。[1]Jensen MD, Ryan DH, Apovian CM, et al; American College of Cardiology/American Heart Association Task Force on Practice Guidelines; Obesity Society. 2013 AHA/ACC/TOS guideline for the management of overweight and obesity in adults: a report of the American College of Cardiology/American Heart Association Task Force on Practice Guidelines and The Obesity Society. Circulation. 2014 Jun 24;129(25 suppl 2):S102-38.http://circ.ahajournals.org/content/129/25_suppl_2/S102.longhttp://www.ncbi.nlm.nih.gov/pubmed/24222017?tool=bestpractice.com[2]World Health Organization. Obesity: preventing and managing the global epidemic. Report of a WHO consultation. Geneva, Switzerland: World Health Organization; 2000.http://whqlibdoc.who.int/trs/WHO_TRS_894.pdf[3]Kopelman PG. Obesity as a medical problem. Nature. 2000 Apr 6;404(6778):635-43.http://www.ncbi.nlm.nih.gov/pubmed/10766250?tool=bestpractice.com[29]Caballero B. The global epidemic of obesity: an overview. Epidemiol Rev. 2007;29:1-5.http://www.ncbi.nlm.nih.gov/pubmed/17569676?tool=bestpractice.com 在绝大多数人群中，BMI 是一种合理的确定肥胖的方法，但在孕妇或有大量肌肉组织（例如职业运动员）的人中并不准确。 另外，BMI并不因性别、年龄或者骨架等因素不同而不同，而这些因素都可以影响脂肪的含量。 尽管存在以上这些缺点，BMI还是标准化的、常用的诊断成人肥胖的方法。
腰围
腰围增加通常被用作肥胖相关疾病风险的标志，并且似乎与高血压、糖尿病、血脂异常和代谢综合征的风险增加有关。[1]Jensen MD, Ryan DH, Apovian CM, et al; American College of Cardiology/American Heart Association Task Force on Practice Guidelines; Obesity Society. 2013 AHA/ACC/TOS guideline for the management of overweight and obesity in adults: a report of the American College of Cardiology/American Heart Association Task Force on Practice Guidelines and The Obesity Society. Circulation. 2014 Jun 24;129(25 suppl 2):S102-38.http://circ.ahajournals.org/content/129/25_suppl_2/S102.longhttp://www.ncbi.nlm.nih.gov/pubmed/24222017?tool=bestpractice.com[103]Pouliot MC, Despres JP, Lemieux S, et al. Waist circumference and abdominal sagittal diameter: best simple anthropometric indexes of abdominal visceral adipose tissue accumulation and related cardiovascular risk in men and women. Am J Cardiol. 1994 Mar 1;73(7):460-8.http://www.ncbi.nlm.nih.gov/pubmed/8141087?tool=bestpractice.com[104]Alberti KG, Zimmet P, Shaw J. The metabolic syndrome - a new worldwide definition. Lancet. 2005 Sep 24-30;366(9491):1059-62.http://www.ncbi.nlm.nih.gov/pubmed/16182882?tool=bestpractice.com[105]Booth ML, Hunter C, Gore CJ, et al. The relationship between body mass index and waist circumference: implications for estimates of the population prevalence of overweight. Int J Obes Relat Metab Disord. 2000 Aug;24(8):1058-61.http://www.ncbi.nlm.nih.gov/pubmed/10951546?tool=bestpractice.com
实验室评估和影像学检查
诊断肥胖并不需要实验室检查和影像学检查。 极少情况下，若怀疑存在肥胖的继发因素或与肥胖相关的临床情况，可行如下实验室检查包括血常规、血电解质、转氨酶、TFTs、以及LFTs。 若临床症状怀疑心脏病可做心电图，若怀疑脂肪肝可做腹部超声。 若怀疑阻塞性睡眠呼吸暂停，可行多导睡眠记录。
身体成分检测
虽然有些实验室方法可以检测身体成分，但没有一个方法是简单、便宜、受欢迎以及可以广泛应用的。 这些检查包括皮褶厚度测量、水下称重法、生物电阻抗分析、DXA 和很多其他检查。[106]Heyword VH, Wagner DR. Applied body composition assessment. 2nd ed. Champaign, IL: Human Kinetics; 2004.
