BIO 111 Lecture Notes - Lecture 20: Lean Body Mass, Dual-Energy X-Ray Absorptiometry, Leptin
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3 other methods of estimating body fatness: density: measure of body weight compared to volume. Lean tissue is denser then fat, therefore, the denser a person"s body is the more lean tissue it must contain. Density can be determined by underwater weight or by air displacement methods: conductivity: measures the body ability to conduct electric current. Only lean tissue and water conduct electrical current. Bioelectric impedance (bia) measures how well a tiny, harmless electrical charge is conducted through the body"s lean tissue. A disadvantage is that fluctuations in the body"s water content can impact results. Water conducts electrical charge, so over hydration can underestimate body fatness, and dehydration can overestimate body fatness: radiographic techniques: images of the body tissues and an assessment of body composition. An example is dual energy x-ray absorptiometry (dexa), which measures two beams of x-ray energy as they pass harmlessly through the body tissue. The beams differentiate between fat-free soft tissue, fat tissue and bone tissue.
