Skinfold (Fatfold) Measurement

The rationale for fatfold measurements is that a relationship exists between the fat located in the depots directly beneath the skin and both internal fat and body density. Approximately 50% of the fat in the body lies beneath the skin, so it is possible to predict overall body fat from subcutaneous measurements.

The source frames total body fat as existing in two sites:

1. Depot, or essential, fat — stored in the marrow of bones, the central nervous system, liver, muscle, intestines, and other internal organs. It is necessary for normal, healthy physiological functioning. Essential fat is about 3–4% in males and 12% in females (including sex-characteristic fat). See essential-fat.
2. Storage fat — stored in adipose tissue; it protects internal organs and is the fat deposited beneath the skin. This is the fat we do not want to accumulate. See storage-fat.

College-age men average about 18% of total weight as fat, while college-age women average about 22%. Men and women who exercise or are physically active tend to have less fat than their untrained counterparts.

• ~50% of body fat lies beneath the skin (subcutaneous).
• Skinfold measurement predicts total body fat from subcutaneous fat, internal fat, and body density relationships.
• Two fat sites: depot/essential fat (internal, ~3–4% male / 12% female) and storage fat (adipose).
• College-age fat averages: ~18% (men), ~22% (women).

• skinfold-accuracy — the five assumptions and sources of error.
• essential-fat — depot/essential fat values.
• storage-fat — adipose storage fat.
• body-composition — overall framework.
• regional-fat-distribution — where the measured fat sits also matters, not just how much.
• skinfold-assessment — the current protocol version of this same method (Jackson-Pollock 3-/7-site equations, ~±3.5% accuracy) with modern technique detail this source doesn't specify (site count, caliper timing, equation choice).
• body-composition-overview — where skinfolds rank among BIA, DEXA, and hydrostatic/Bod Pod -- skinfolds remain a solid field method, not superseded, just one option among several with different accuracy/cost tradeoffs.