Comparison of methods for assessing body composition changes during weight loss.

Area of Science:

• Human Physiology
• Body Composition Analysis
• Weight Management

Background:

• Percent body fat (%BF) measurements vary between dual-energy x-ray absorptiometry (DXA) and air displacement plethysmography (ADP).
• Previous studies indicate higher %BF with DXA compared to ADP in normal-weight individuals.
• Overweight populations require similar comparative analysis of these body composition methods.

Purpose of the Study:

• To confirm if DXA yields higher %BF than ADP in overweight individuals.
• To assess if DXA and ADP detect similar body composition changes after weight loss.
• To compare fat mass (FM) and fat-free mass (FFM) estimations between DXA and ADP.

Main Methods:

• Cross-sectional study involving 12 women and 10 men (mean age 40-42 years).
• Body composition measured using DXA and ADP before and after an 8-week weight loss program.
• Weight loss involved moderate energy restriction and exercise.

Main Results:

• Significant body weight reduction observed in both women and men.
• DXA and ADP showed significant differences in estimating %BF, FM, and FFM.
• ADP estimates were lower for %BF and FM, and higher for FFM compared to DXA.
• High correlations (r=0.98-0.99) existed between DXA and ADP for %BF, FM, and FFM.
• Correlations for changes in %BF, FM, and FFM were lower (r=0.34-0.86).
• No significant differences in mean changes of %BF, FM, and FFM between methods post-weight loss.

Conclusions:

• DXA and ADP are comparable in measuring body composition changes after moderate weight loss.
• Both methods demonstrate similar sensitivity in detecting changes in %BF, FM, and FFM.
• These findings support the use of either DXA or ADP for tracking body composition adjustments during weight management programs.