Body composition describes the percentages of fat, bone and muscle in your body. These percentages provide an overall view of your health and fitness in relation to your weight, health, and age. Weight and fat are often used together, but they are not interchangeable. Being overweight does not imply obesity - in fact, many physically fit people are overweight due to muscle gain. However, being "overfat" poses health risks. This version is the first release on CNET Download.com.