Date of Award

Spring 5-9-2015

Degree Type

Thesis

Degree Name

Master of Science (MS)

Department

Nutrition

First Advisor

Dr. Dan Benardot

Second Advisor

Dr. Anita Nucci

Third Advisor

Dr. Walter Thompson

Abstract

Background: Previous research suggests associations between energy balance, eating frequency, macronutrient content, and macronutrient distribution with body composition. In particular, energy balance and protein intake have been conventionally evaluated in 24-hr time blocks, consistent with dietary recommendations and general public understanding. However, there is a potential benefit to investigating energy balance and protein intake in smaller increments of time to account for dynamic changes that occur within-day.Objective: The purpose of this study was to evaluate protein intake/distribution relative to energy balance fluctuations during the day and body composition in collegiate female basketball players.Methods: Subjects provided information on dietary intake and expenditure. Body composition was assessed by multi-current bioelectrical impedance. Energy balance (EB) and related protein distribution variables were determined with a Computerized Time-Line Energy Analysis procedure. Data were analyzed for associations between energy balance, protein intake and distribution, and body composition. Data are displayed as either traditional 24-hr EB and total protein intake or dynamic protein variables in relation to real-time EB (ingestion within ± 400 kcal EB or > 0 kcal EB).Results: There was no relationship between net 24-hr energy balance and percentage body fat. A statistically significant positive relationship was observed between total protein intake and body fat mass (R = .597; p = .031). No relationship was observed between protein distribution variables (g in ± 400 kcal EB, g in > 0 kcal EB) and percentage body fat. Protein eating occurrences (>10g, ± 400 kcal EB) was inversely correlated with BMI (R = -.650; p = .016). Subjects with the greatest energy deficits presented with lower lean body mass (R= -.736; p = .004).Conclusion: These data suggest that within-day protein distribution relative to energy balance are associated with BMI, but not with percentage body fat. Those with the highest protein intake had the highest body fat mass, with no correlation between protein intake and total energy intake detected. In this group, no association between 24hr intake net values or within-day intake values were found to be related to body fat percentage. However, the greatest energy balance deficit during the day was strongly inversely associated with lean body mass, indicative of potentially deleterious effects of energy restriction.

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