Lean body mass

Lean Body Mass is a component of body composition, calculated by subtracting body fat weight from total body weight: total body weight is lean plus fat. In equations:

LBM = BW − BF

Lean Body Mass equals Body Weight minus Body Fat

LBM + BF = BW

Lean Body Mass plus Body Fat equals Body Weight

The percentage of total body mass that is lean is usually not quoted – it would typically be 60–90%. Instead, the body fat percentage, which is the complement, is computed, and is typically 10–40%. The Lean body mass (LBM) has been described as an index superior to total body weight for prescribing proper levels of medications and for assessing metabolic disorders, as body fat is less relevant for metabolism.

Estimation of Lean body mass

LBM is usually estimated using mathematical formulas.

The following formula may be used:^[1]

For men : LBM = (0.32810 * W) + (0.33929 * H) - 29.5336

For women : LBM = (0.29569 * W) + (0.41813 * H) - 43.2933

where W is body weight in kilograms and H is body height in centimeters.

A Nomogram based on height, weight and arm circumference may be used.^[2]

Actual measurement of LBM

Instead of mathematical estimation the actual value of LBM may be calculated using various technologies such as dual energy X-ray absorptiometry (DEXA).

References

1. Hume, R (Jul 1966). "Prediction of lean body mass from height and weight." (PDF). Journal of clinical pathology 19 (4): 389–91. doi:10.1136/jcp.19.4.389. PMC 473290. PMID 5929341.
2. Fuchs, RJ; Theis, CF; Lancaster, MC (Apr 1978). "A nomogram to predict lean body mass in men.". The American Journal of Clinical Nutrition 31 (4): 673–8. PMID 637039.