| Objective:
This study had two objectives: to determine the validity of
the leg-to-leg bioelectrical impedance (BIA) system in 1) estimating
body composition in obese and non-obese women cross-sectionally,
and 2) assessing changes in body composition in obese females
in response to 12 weeks of energy restriction and/or exercise
training
Design:
Subjects included 98 moderately obese females (43.2±0.6%
fat, 45.0±1.1 years) and 27 non-obese controls (24.0±1.5%
fat, 43.5±2.5 years). Obese subjects were randomly divided
into one of four groups, with fat-free mass (FFM), fat mass (FM)
and percent body fat estimated pre and post-12 weeks intervention
from BIA and underwater weighing. The four groups were diet only
(D) (4.19-5.44 MJ/day), exercise only (E)(five 45 min. sessions/week
at 78.5±0.5% maximum heart rate), both exercise and diet
(ED) and controls (C) (no diet or exercise). |
Results:
No difference was found between underwater weighing and BIA
in estimating the FFM of obese and non-obese females (all subjects
combined, r=0.78, P<0.001, SEE=3.7kg), or in estimating decreases
in FM during 12 weeks of energy restriction and/or exercise among
obese subjects [F(3.85)=1.45, P=0.233].
Conclusion:
The leg-to-leg bioelectrical impedance system accurately assessed
FFM in both obese and non-obese females, and changes in FM through
diet alone or when combined with exercise.
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