Which statement about BMI is true?

• A. BMI directly measures body fat percentage.
• B. BMI is a ratio of height to weight, but not used for health screening.
• C. BMI is a ratio of weight to height.
• D. BMI is primarily a measure of bone density.

Answer: (C)

BMI relates weight to height to estimate whether someone falls into categories like underweight, normal, overweight, or obese, and is used as a quick health-screening tool rather than a direct measure of body fat. The best statement is that BMI is a ratio of weight to height. In practice, it’s calculated as weight in kilograms divided by the square of height in meters, which adjusts weight for a person’s height. This relationship is what lets BMI reflect weight status across different heights, unlike claims that it measures fat directly or bone density or that it isn’t used for screening. Remember, BMI has limits: it can’t distinguish fat from muscle and may misclassify some individuals.