Body composition refers to the proportion of different components that make up the human body, primarily fat mass and lean body mass. It includes the percentage of body fat relative to lean tissues such as muscle, bone, water, skin, and other organs. Body composition is often expressed as the percentage of total body weight that is fat versus lean mass. Unlike simply measuring weight or body mass index (BMI), body composition gives a more detailed insight into health and fitness because muscle is denser than fat, and two people with the same weight can have very different health profiles depending on their fat and muscle proportions. Body fat plays important roles in the body including hormone production, insulation, and energy storage, but excess body fat increases the risk of health problems such as heart disease, diabetes, and joint issues. Lean body mass includes bones, muscles, organs, and other tissues necessary for body function. Body composition is commonly used in fitness and medical contexts to assess health status, design exercise programs, and monitor changes over time. Methods to measure body composition range from simple skinfold calipers and bioelectrical impedance to more advanced techniques like air displacement plethysmography (Bod Pod), dual X-ray absorptiometry (DEXA), and underwater weighing. In summary, body composition is the breakdown of the body into fat and non-fat components, providing a clearer picture of an individual's health than weight alone. It helps distinguish between fat mass, muscle, bone, and other vital tissues, and is key for understanding physical fitness and risks associated with excess fat or muscle deficiency.
