Which model involves relative fat mass and fat-free mass?

The model that involves relative fat mass and fat-free mass is the two-component model. This model divides body composition into two main categories: fat mass, which includes all the fat tissue in the body, and fat-free mass, which encompasses everything else—muscles, bones, water, and organs.

This approach simplifies the assessment of body composition, making it easier to understand the proportion of body weight represented by fat versus lean tissue. In practical applications, such as fitness and health assessments, the two-component model is widely used because it provides essential insights into an individual's biological makeup and helps in tailoring personalized health and fitness programs.

Other models, such as the three-component, four-component, and five-component models, introduce additional layers of complexity by further dividing body composition into other elements, such as water and mineral content, but the two-component model specifically emphasizes the distinction between fat and fat-free mass.