Answers from Expert: Michelle Cederberg

Fat-free mass refers to all parts of the body tissues not containing fat. These tissues include skeletal bones and muscles, skin, organs and body water, as well as hair, blood, and lymph. When we talk about an increase in overall fat-free mass, it usually pertains to an increase in skeletal muscle, such as when you have been weight training to add muscle. By comparison, fat mass is the actual fat mass (in pounds or kilograms) in the body. There are a number of methods available for estimating your fat mass, usually through a per cent of body fat measure. These days you can purchase home weigh scales that estimate this figure. Most have a "foot pad" that sends a low, safe electrical current through the body to measure its composition. The electrical current passes more easily through lean muscle than fat and body composition is calculated mathematically, based upon the speed at which the signal passes through the body. The scales certainly give you an idea of where you stand and can indicate accurate change over time, but the validity of the actual percentage is low. A more clear-cut option is to have a certified fitness appraiser measure your skinfolds and calculate an estimate using measures from various sites on your body. This method gives you more direct evidence of where you store higher or lower than normal fat deposits, but it isn't perfect either. Good results depend on skillful measures and accurate repeat measures, and even still, the error can be high. If you're interested in finding out more, ask a qualified fitness professional about options for determining per cent body fat. Good luck. Michelle Cederberg, MKin, PFLC www.liveoutloud.ca