Utility of the SenseWear Pro 3 armband monitor and the Weight Management System for evaluating energy balance in adults
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The progression of the obesity epidemic stems directly from the inability of individuals to achieve a balance between energy expenditure (EE) and energy intake (EI). To enhance research on obesity prevention it is important to develop and validate instruments that can facilitate monitoring of energy balance (EB) under free-living conditions. The SenseWear Pro 3 armband (SWA) monitor and associated weight management system (WMS) offer promise as a non-invasive method suitable for energy balance research. The primary purpose of the study was to evaluate the utility of the SWA and WMS to assess EB during a week of free-living activity. A total of 68 healthy adult participants (31 male and 37 female) wore the SWA monitor for a week while recording a detailed 7-day dietary food record. Estimates of EE were obtained directly from the SWA software. Estimates of EI were obtained by entering the dietary food records into both the Nutritionist Pro and the SenseWear WMS dietary assessment systems. The estimated EB (EI-EE) was compared with the observed EB (obtained from fasted weight measures taken at the beginning and ending of the study). Differences in EB values (observed - estimated) were statistically tested using standard t-tests. A secondary purpose was to compare the assessed EI between Nutritionist Pro and SenseWear WMS. A mixed model analyses of variance was used to evaluate the difference between EI values as well as macronutrient intakes of carbohydrate, fat, and protein. Results indicated that participants lost weight during the week long protocol (mean weight loss = -0.5 y 1.6 lbs) without an apparent intention to lose weight. Similarly, estimated EB was significantly different than zero, indicating a negative EB (weight loss). Difference in weight difference (observed - estimated) was positive (difference = 0.9 lbs y 2.0), indicating a significant overestimation of weight loss (p < 0.001). Supplemental analyses indicated that individuals completing more detailed dietary records had a significantly higher weight loss than those providing less detailed records. More interestingly, individuals providing high quality dietary records had a small (non-significant) average EB difference (difference = -0.03 y 1.4 lbs, p = 0.09) while individuals providing poor quality records had large EB differences (difference = 2.0 y 1.0 lbs, p < 0.001). Collectively, this suggested that the estimates of EB from the WMS are accurate when participants provided detailed dietary records. Correlations between nutrient intake (EI, protein, carbohydrate, and fat) assessments (SenseWear WMS vs. Nutritionist Pro) were high for all comparisons (range: r = 0.93 to 0.99). The estimates of EI from the two dietary assessment systems were not significantly different (p = 0.07) and the gender by method interaction was also not significant (p = 0.32). Similar results were noted for macronutrient comparisons; however, a significant gender by method interaction was evident for protein (p = 0.048). In conclusion, the SWA monitor with its integrated WMS demonstrated promising attributes for assessing EB in free-living individuals.
Key Words: activity monitors, energy balance assessment, dietary assessment system