Fat weight is excess baggage for the body and this can be a detriment to health. The most accurate way to measure lean weight is to weigh a person underwater. This is done by scientists for research mainly on athletes. It is not practical for everyday use. Skinfold measurements using special calipers are more practical for estimating the fat and lean components of total body weight.
Skinfold measurements are available at most health clubs that have certified fitness instructors.
Some health clubs provide circumference measurements of the arms, legs, and trunk to estimate lean and fat weight. These measurements are not sensitive to changes that take place in the lean and fat components of the body. For example, after being sedentary for several months, the fat component may decrease without any change taking place in the leg circumference. Skinfold measures would be more accurate in detecting the increase in leg fat in this example. Bioelectric impedance is also used by some health clubs to estimate the amount of fat and lean in the body.