Obesity Definitions and Diagnostic Criteria

Population-Specific Definitions

• The World Health Organization and other guideline societies recommend using ethnicity-specific BMI thresholds for South and Southeast Asian populations, with overweight defined as BMI ≥23 kg/m² or waist circumference ≥80 cm for women and ≥90 cm for men 1
• The American Heart Association defines severe pediatric obesity as BMI ≥120% of the 95th percentile or absolute BMI ≥35 kg/m², whichever is lower based on age and sex, replacing the previous 99th percentile cutoff due to statistical instability 2, 3, 4

Recognition as Chronic Disease

• The American Medical Association recognizes obesity as a complex, chronic disease requiring ongoing medical attention, with a multifactorial etiology involving genetics, metabolism, environment, and social determinants, and a progressive nature with potential for severe end-organ damage 5, 3

Clinical Implications of New Definitions

Assessment Requirements

• The American Heart Association recommends systematic evaluation of all patients with confirmed excess adiposity for clinical obesity, including assessment of cardiovascular function, metabolic function, respiratory function, and psychosocial functioning 7

Treatment Prioritization

• The American College of Cardiology and other guideline societies recommend immediate, evidence-based treatment for patients with clinical obesity, which may include pharmacotherapy, bariatric surgery, or endoscopic procedures, rather than just lifestyle counseling 6

Critical Pitfalls to Avoid

• The World Health Organization and other guideline societies advise against relying on BMI alone for clinical decision-making, as it may underestimate adiposity in some patients or overestimate health risk in others, and against delaying treatment in patients with functional impairment 1