Body Composition — Key Terms (Vocabulary)

Vocabulary flashcards covering key terms and definitions from the CH6 Body Composition notes.

fat-free mass

All nonfat tissues of the body (bone, water, muscle, connective tissue, organ tissues, teeth).

body fat

Fat stored in adipose tissue; includes essential fat and nonessential fat; essential fat is necessary for normal function (about 3–5% of body weight in males and 8–12% in females).

essential fat

Fat necessary for basic physiological function; typically 3–5% of body weight in males and 8–12% in females.

visceral fat

Fat located around major organs in the abdomen; more harmful to health than subcutaneous fat.

subcutaneous fat

Fat located just under the skin.

percent body fat

The percentage of total body weight that is fat.

overweight

Excess body fat beyond a healthy range; commonly defined as BMI 25.0–29.9 or similar excess fat regardless of weight.

obesity

Severe overweight; BMI typically ≥30 or high fat accumulation with increased health risks.

Body Mass Index (BMI)

A ratio of weight to height calculated as weight (kg) divided by height (m)²; used to classify weight status.

BMI classifications

Underweight <18.5; Normal 18.5–24.9; Overweight 25.0–29.9; Obesity Class I 30.0–34.9; Class II 35.0–39.9; Class III ≥40.

waist circumference

Measurement around the abdomen used to assess fat distribution and disease risk; higher values indicate greater risk.

waist circumference cutoffs

High risk thresholds: men >40 inches (102 cm), women >35 inches (88 cm).

waist-to-hip ratio

Waist circumference divided by hip circumference; another measure of fat distribution.

waist-to-hip ratio cutoffs

Higher risk: men >0.94, women >0.82.

metabolic syndrome

Cluster of conditions (e.g., large waist, high BP, high fasting glucose, high triglycerides, low HDL) that increase risk of heart disease and diabetes; diagnosis requires at least three factors.

female athlete triad

Three interrelated disorders: abnormal eating/excessive exercise, amenorrhea, and decreased bone density (osteoporosis).

energy balance

The relationship between energy intake (food) and energy expenditure (basal/resting metabolism, digestion, and physical activity).

resting metabolic rate (RMR)

Energy required to maintain vital body functions at rest; accounts for about 65–70% of daily energy expenditure.

set-point theory

Idea that body weight is regulated to stay within a narrow range; weight can change with long-term lifestyle factors, but metabolic adaptations can resist loss.

fat cells (adipocytes)

Cells that store fat; number may be determined genetically; fat content can change without changing cell number.

liposuction

Surgical removal of fat from specific areas; not a primary method for long-term weight loss and carries risk.

underwater weighing

A body composition assessment where body density is determined by hydrostatic weighing; used to estimate percent body fat.

Bod Pod

Air displacement plethysmography; estimates body composition by measuring air displacement to determine body density.

skinfold measurements

Assessment of body fat by measuring thickness of skinfolds at several sites and using equations to estimate percent fat.

bioelectrical impedance analysis (BIA)

TECHNIQUE: passes a small electrical current through the body; resistance estimates fat-free mass and percent body fat (margin of error ~±4–5%).

DEXA

Dual-energy X-ray absorptiometry; a precise method to measure body composition with margin of error around ±2%.

TOBEC

Total body electrical conductivity; estimates lean body mass using a magnetic field; used mainly in research.

U.S. Navy circumference method

Method to estimate percent fat using abdominal, neck (and hip for females) measurements with height; includes navigation charts.

somatotype

Big-picture body type classification: endomorph (round), mesomorph (muscular), ectomorph (linear).