Body composition refers to the proportion of fat, muscle, bone, and other tissues in the body, whereas body weight only measures total mass. Evaluating body composition provides a more comprehensive health assessment, as it distinguishes between lean tissue and fat mass. A higher muscle-to-fat ratio is often associated with better health outcomes, such as improved metabolic function and physical performance. In contrast, focusing solely on body weight may obscure these important health aspects, potentially leading to misinformed health and fitness decisions.