Body Mass Index (BMI): Five Key Facts

1. Definition: BMI = weight (kg) / height (m)² — estimates body fatness from anthropometrics.
2. Categories: <18.5 underweight, 18.5–24.9 normal, 25–29.9 overweight, ≥30 obese (I/II/III).
3. Screening utility: Simple, inexpensive, non-invasive, population-level correlate of cardiometabolic risk.
4. Limitations: Doesn't differentiate fat vs. lean mass; misclassifies muscular, elderly, Asian populations (lower cutoffs); ignores fat distribution.
5. Best practice: Use with waist circumference, body composition, blood pressure, lipids, glucose for comprehensive assessment.