"Body composition assessment is a physical test that measures the proportion of the various components of a person's body. The human body is comprised of water, protein, fat, and minerals, but for most purposes, it is the level of fat compared to lean mass that is of interest. In general, most body composition analysis tests measure the ratio of fat to lean tissue. Body fat, or adipose tissue,has chemical and physical properties that allow for a number of analytical methods, each with its own advantages and limitations."