Body composition refers to the proportion of different components that make up the human body, typically expressed as percentages of fat mass and lean mass (including muscle, bone, water, and other tissues). It looks beyond total body weight to detail how much of the body is fat compared to muscles and other non-fat tissues. Monitoring body composition gives insights into fitness, health risks, and nutritional status because excess body fat can increase the risk of diseases while lean mass supports metabolic functions and physical performance.