Reference View Full Guide Medically Reviewed by Zilpah Sheikh,MD on June 24, 2024Written by Jody Braverman5 min readBody composition is a term often used often by doctors and health and fitness professionals. It refers to the percentage of fat, bone, and muscle in your body. It can give your doctor a better idea of your physical health and fitness than your body weight alone. Your doctor may use it to learn more about your nutrition, health status, and risks of disease. In the fitness world, it's used to keep track of how effective a particular program is for fat loss and muscle gain.Why Is Body Composition Important?Weighing yourself only tells you one thing: your total weight. Body composition, on the other hand, gives you a much more detailed picture of your weight health because muscle is denser than fat. Someone with lots of muscle can weigh more than someone with a lot of extra fat, even though they look leaner.Making this distinction helps you have a clearer picture of your fit...