Essential Body Fat

Some body fat is essential: it serves as an energy store, protects internal organs, is a component of nerves and cell membranes, and insulates against heat loss. Essential body fat is 3% to 5% of total body weight for adult males and 11% to 14% for adult females. These values represent the lower limits of body fat necessary to maintain good health. The larger quantity of fat in females presumably relates to childbearing functions.

A second passage in the source (page 484) frames the total body fat as existing in two sites — depot (essential) fat stored in bone marrow, central nervous system, liver, muscle, intestines, and other internal organs (necessary for normal, healthy physiological functioning), and storage fat in adipose tissue. In that passage essential fat is given as 3–4% in males and 12% in females (including sex-characteristic fat). The two passages give slightly different female figures (11–14% vs. 12%) and male figures (3–5% vs. 3–4%); both are preserved here.

• Essential fat (page 124): 3%–5% (adult males), 11%–14% (adult females) of total body weight.
• Essential/depot fat (page 484): 3–4% (males), 12% (females, including sex-characteristic fat).
• These are the lower limits of body fat needed for good health.
• The greater female fat quantity is presumably related to childbearing.

• body-composition — essential fat is part of fat mass.
• obesity-thresholds — the upper end of body-fat percentages.
• storage-fat — the adipose-tissue site of fat we don't want to accumulate.
• body-fat-norms — current ACSM/ACE essential-fat figures (~2-5% men, ~10-13% women) sit close to this source's numbers, confirming they still hold up.