fat-free body mass

Also found in: Acronyms.

fat-free bod·y mass

(FFM) (fat'frē bod'ē mas)
Body mass, primarily of muscle and bone, devoid of storage fat; a theoretic entity that contains the small percentage of non-sex-specific essential fat equivalent to approximately 3% of body mass (located chiefly within the central nervous system, bone marrow, and internal organs).
Synonym(s): lean body mass.
References in periodicals archive ?
Total body water is then used to estimate fat-free body mass and--by calculating the difference with body weight--body fat.
The study highlights the importance of adequate sleep for maintenance of fat-free body mass when dieting to lose weight.