Which BMI range defines underweight in adults?

Which BMI range defines underweight in adults?

• A. 18.5-24.9 kg/m²
• B. <18.5 kg/m²
• C. 25.0-29.9 kg/m²
• D. 30.0-34.9 kg/m²

Answer: (B)

BMI categories help classify weight status in adults by comparing weight to height. Underweight is defined as a BMI below 18.5 kg/m^2. This threshold comes from the World Health Organization’s classification, with the normal range defined as 18.5–24.9, overweight as 25.0–29.9, and obesity starting at 30.0. The reason this is the best answer is that being below 18.5 indicates weight not sufficient for height according to these standard cutoffs used in clinical practice. Remember, BMI is a screening tool, not a direct measure of body fat, and it can misclassify individuals with unusual body composition.

BMI categories help classify weight status in adults by comparing weight to height. Underweight is defined as a BMI below 18.5 kg/m^2. This threshold comes from the World Health Organization’s classification, with the normal range defined as 18.5–24.9, overweight as 25.0–29.9, and obesity starting at 30.0. The reason this is the best answer is that being below 18.5 indicates weight not sufficient for height according to these standard cutoffs used in clinical practice. Remember, BMI is a screening tool, not a direct measure of body fat, and it can misclassify individuals with unusual body composition.