In vivo measurement of changes in body composition: description of methods and their validation against 12-d continuous whole-body calorimetry.
The accuracy of a variety of in vivo body-composition techniques (densitometry, total body water, skinfold thicknesses, whole-body impedance and resistance, body mass index, and two three-compartment models) was assessed by comparison with fat balance. Three subjects were overfed and three underfed while confined to a 30-m3 whole-body calorimeter continuously for 12 d. Mean weight changes were +2.90 kg during overfeeding and -3.47 kg during underfeeding. The change in fat mass accounted for 37.1% during overfeeding and 59.3% during underfeeding. In comparison with energy and nitrogen balance, a three-compartment model yielded the least bias and greatest precision. The smallest change in fat mass that can be measured by such a method in an individual subject is 1.54 kg (2 SD). Of the prediction techniques considered, skinfold thicknesses or the body-mass-index formula appear to be more precise than estimates based on resistance or impedance.
MRC Dunn Clinical Nutrition Centre, Cambridge, UK.
S A
SA
Jebb
P R
PR
Murgatroyd
G R
GR
Goldberg
A M
AM
Prentice
W A
WA
Coward
D000293:Adolescent; D000328:Adult; D001823:Body Composition; D001834:Body Water / Q000737:chemistry; D001835:Body Weight; D002151:Calorimetry / Q000379:methods*; D002149:Energy Intake; D004734:Energy Metabolism; D005508:Food Deprivation; D006801:Humans; D006963:Hyperphagia; D008297:Male; D010084:Oxidation-Reduction; D011188:Potassium / Q000032:analysis; D012885:Skinfold Thickness
D011188:Potassium