In the context of assessing weight-related health risk, BMI is most reliably used as an indicator of total body _____.

• A. hydration status (total body water)
• B. bone mineral density
• C. lean muscle mass
• D. fatness (overall adiposity)

Answer: (D)

Verified step by step guidance

1. Understand that BMI (Body Mass Index) is a calculation based on a person's weight and height, given by the formula \(BMI = \frac{weight\ (kg)}{height\ (m)^2}\).
2. Recognize that BMI is used as a screening tool to categorize individuals into weight categories such as underweight, normal weight, overweight, and obese, which relate to body fat levels.
3. Note that BMI does not directly measure body composition components like hydration status, bone mineral density, or lean muscle mass, but rather provides an estimate of overall body fatness or adiposity.
4. Recall that total body fatness (adiposity) is the primary health risk factor associated with BMI, as excess fat is linked to various metabolic and cardiovascular diseases.
5. Conclude that among the options given, BMI most reliably indicates total body fatness (overall adiposity) rather than hydration status, bone mineral density, or lean muscle mass.