fat-free body mass


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.