Body fat percentage measures the proportion of body mass composed of fat. For example, a person weighing 150 pounds with 25 pounds of body fat has a body fat percentage of 25% (25/150 x 100%). Body fat percentage is a more accurate indicator of health and fitness than weight alone, as it takes into account individual body composition. It is used to assess risk factors for certain diseases, such as obesity, cardiovascular disease, and diabetes.
Measuring body fat percentage became more accessible with the development of bioelectrical impedance analysis (BIA) in the 1960s. This method uses a small electrical current to estimate body composition. BIA devices are widely available and relatively inexpensive, making them a popular option for measuring body fat percentage.