Variations In Body Composition Derived Energy Balance Across Throughout Six Weeks Of Overfeeding

PURPOSE: Energy balance (EB) knowledge is crucial for weight management and optimizing athletic performance. A positive, or neutral EB, is vital for proper recovery and increasing body mass (BM) and fat free mass (FFM). While, a prolonged negative EB is necessary for weight loss, however, if unmanaged can lead to numerous deleterious effects. Changes in dual-energy X-ray absorptiometry (DXA) fat mass (FM) and FFM have previously been used to estimate average daily EB. However, little is known about this relation to other body composition devices. Thus, the purpose of this investigation was to assess the variance between the established DXA derived EB method and EB estimated from other body composition devices. METHODS: 21 males (Age: 21.9 ± 2.6 yrs; Weight:74 ± 10.9 kg; BF%:15 ± 9.5) completed a 6-week overfeeding and supervised resistance training protocol in which they were required to gain ≥0.45 kg of BM per week. Body composition was assessed at pre and post by DXA, BIA, BIS, digital anthropometry (Fit3D, SS), ADP, and 4-compartment model (4C). Averaged daily EB across the 6 weeks was estimated via changes in FM and FFM from each body composition method used in the following equation: EB = (∆FFM/∆t) + (9.5*∆FM/∆t) where ∆t represents the days between assessments. A one-way repeated measures ANOVA was performed to assess differences in EB across methods. Significance was accepted at p ≤ 0.05. RESULTS: A main effect of method was seen (p < 0.001). Post hoc pairwise comparisons with a Bonferroni correction revealed significant differences between Fit3D (1041+/-873 kcals/day; p = 0.006) and BIS (75+/-358 kcals/day; p = 0.004) when compared to DXA criterion (397+/-324 kcals/day). CONCLUSIONS: Fit3D had overestimation by 644.8 kcals/day on average when compared to DXA while BIS underestimated by 321.7 kcals/day. These data suggest BIA, BIS, ADP, SS, and 4C may provide comparable EB estimations to DXA. However, Fit3D and BIS should not be used in place of DXA derived EB.