Body Composition – LBM and Body Fat %
Body weight is the sum of the skeletal mass, the muscle tissue, the organs, the body fluids and the adipose tissue. The relative proportion of all these is referred to as the body composition.
It is influenced by many factors and is subject to change. Water makes up 65-70% of the body weight and is the most variable component depending on the state of hydration.
According to the original two component model for body composition measurement, the body was separated into two components –
Fat Mass, including essential and non- essential fat; and
Fat-free Mass, including protein, water, carbohydrate (glycogen) and minerals.
However, a more practical approach is to bifurcate body composition into Adipose Tissue (Body fat %) and Lean Body Mass (all non-adipose tissue, mainly muscle mass).
Lean Body Mass (LBM)
It consists of mainly the muscle tissue and all other non-adipose tissue such as bones, body fluids, organs and essential body fat. Essential body fat is the fat stored in the bone marrow, visceral/internal organs, muscles, and that present in the tissue of the central nervous system and all cell membranes. It is so-named because it is essential for normal physiological functioning. In females, an extra 5-9% sex-specific fat is present in the breast, pelvic regions and thighs.