What does the term "body mass index" (BMI) primarily assess?

The term "body mass index" (BMI) primarily assesses weight relative to height. It is calculated by taking a person's weight in kilograms and dividing it by the square of their height in meters. This ratio provides a general indication of whether an individual is underweight, normal weight, overweight, or obese based on established thresholds.

BMI is widely used because it is a simple and quick tool that does not require complex measurements or specialized equipment. While it can provide insight into weight status, it does not directly measure body fat percentage, body composition, or lean muscle mass. Therefore, it gives a broad overview of weight relative to height rather than detailed insights into an individual’s overall body composition or the distribution of muscle and fat.