What are the BMI categories?

Underweight: below 18.5. Normal weight: 18.5–24.9. Overweight: 25.0–29.9. Obese Class I: 30–34.9. Obese Class II: 35–39.9. Obese Class III: 40 and above.

Is BMI accurate for athletes?

BMI often overestimates fatness in muscular individuals. A bodybuilder may have a BMI of 30+ despite very low body fat. Waist circumference and body fat percentage are more informative for athletes.

Is BMI calculated differently for children?

Yes. For those under 20, BMI is calculated the same way but then plotted on age- and sex-specific growth charts. A percentile, not a fixed number, determines the weight category.

How does ethnicity affect BMI interpretation?

Research shows that Asian populations have higher health risks at lower BMI values. The WHO recommends lower cut-off points for Asian populations (overweight at 23, obese at 27.5).