Which of the following best defines body mass index (BMI)?

Body Mass Index (BMI) is a numerical value derived from an individual's weight and height, which is used to categorize them into different weight status categories—underweight, normal weight, overweight, and obesity. This classification helps in identifying potential health risks related to weight, allowing healthcare professionals to assess whether a person falls within a healthy weight range.

The formula for calculating BMI is weight in kilograms divided by height in meters squared (kg/m²). This straightforward calculation provides a quick screening tool to identify individuals who may be at risk of weight-related health issues without requiring complex measurements of body composition.

Other options presented may refer to aspects of body composition and fat distribution, but they do not accurately summarize the primary purpose and function of BMI in public health assessments. For example, while measures of body density and lean versus fat mass are important in understanding body composition, they are not what BMI specifically represents. Similarly, a representation of visceral fat is more detailed than what BMI measures, which does not differentiate between types of body fat but rather provides a simple approximation based on height and weight.