Cellular-level body composition model. A new approach to studying fat-free mass hydration.
Fat-free mass hydration, the ratio of total body water (TBW) to fat-free mass (FFM), is stable at approximately 0.73 in mammals, and this constancy provides a means of estimating total body fat in vivo. As there is no mechanistic theory to explain the magnitude and variability in TBW/FFM, the present investigation describes a cellular-level model indicating that FFM hydration is determined by four factors: body cell mass hydration, extracellular fluid hydration, ratio of extracellular solids to TBW, and ratio of extracellular water to intracellular water. According to the model, TBW/FFM can be predicted for adult humans as a mean of 0.73, and a variation range 0.69-0.77. The suggested modeling approach provides a conceptual framework for TBW-fat estimation method and identifies important areas that remain to be studied.
Wang
Z
Z
Obesity Research Center, St. Luke's/Roosevelt Hospital, Columbia University, College of Physicians and Surgeons, New York, New York 10025, USA. ZW28@Columbia.edu
Deurenberg
P
P
Heymsfield
S B
SB
D000273:Adipose Tissue; D000328:Adult; D000375:Aging; D000818:Animals; D001823:Body Composition; D001834:Body Water; D001835:Body Weight; D005110:Extracellular Space; D006801:Humans; D007424:Intracellular Fluid; D008322:Mammals; D008954:Models, Biological; D012016:Reference Values; D015203:Reproducibility of Results