Doctor of Philosophy / Department of Human Nutrition / Mark D. Haub / Background: Mixed Martial Arts (MMA) is a growing sport that places competitors into specific weight classes to level the competition field. Athletes “cut weight” to compete in a weight class lower than their “walk around” weight. Techniques for cutting weight include dehydration, starvation and exercise in hot environments jeopardizing health and performance. Higher-protein diets (HPD) have been shown to improve weight loss by increasing satiety, thermogenesis, decreasing total energy intake, and maintain lean mass during periods of energy deficiency, such as weight loss. Research regarding the impact of HPD on performance is limited and conflicting. Specific Aims: The central hypothesis for this study was: HPD diets will elicit greater weight loss and enhance body composition compare to tradition low-fat diets in non-obese, active individuals. The three specific aims of this study are: 1) examine the effects of HPD on weight loss, 2) evaluate the impact of HPD of athletic performance, and 3) determine the effectiveness of HPD for accelerated weight loss. Methods: Military personnel participating in the Combatives program were recruited. Participants were assigned a HPD (40% CHO, 30% PRO, 30% fat), traditional low-fat, high-carbohydrate diet (65% CHO, 15% PRO, 20% fat), or an ad libitum diet for 12-day to 6-weeks depending on their training program. Fields tests for pre- and post-intervention measures of performance included: vertical jump and leg power index to measure explosive power, 600 meter shuttle run for anaerobic capacity and 1.5 mile run for aerobic capacity. Pre- and post-intervention of weight and body composition were determined using dual energy x-ray absorptiometry. Diet analysis software was used to determine nutrient intakes during the study. SPSS statistical software was used to determine descriptive statistics, paired t-tests, Pearson’s Correlations and one-way ANOVA. Results & Conclusions: Due to the unanticipated high rate of dropout, statistical significance was difficult to determine, however, there was a trend for the HPD to elicit fat-free mass retention and it not negatively impact performance. Discrepancies in energy and nutrient intake made dietary comparison difficult. Future studies with larger samples and greater dietary control are needed to further evaluate the research goals of this study.

<p>Energy restriction-induced weight loss results in the loss of both fat mass (FM) and fat free mass (FFM). Declines in FFM, comprised mostly of skeletal muscle, have the potential to impair metabolic health. A recent meta-analysis demonstrated higher protein hypo-energetic diets (≥ 1.25 g/kg/d) can help retain FFM (Weinheimer, Sands, & Campbell, 2010). This effect is attributed to protein ingestion induced stimulation of muscle protein synthesis (MPS), which is dependent on protein source (Tang, Moore, Kujbida, Tarnopolsky, & Phillips, 2009). However, protein source on modulating FFM preservation during ER remains understudied. In a double blind investigation, 40 adults (BMI 28-40) undertook a moderate 14 day hypo-energetic diet. Subjects were randomized to be supplemented twice daily with whey (WHEY) or soy (SOY) protein, or a carbohydrate (CHO) powder as part of their ER diet. Preliminary and post diet intervention testing included skeletal muscle biopsies, blood samples and DXA measures. Absolute changes in body mass (-2.3 ± 0.18 kg), FM (-1.2 ± 0.16 kg) and FFM (-0.8 ± 0.24 kg) did not significantly differ between groups. Basal serum cortisol was unchanged in WHEY but increased significantly in SOY and CHO (p</p> / Master of Science in Kinesiology

<p>Obesity is a major health concern. Strategies to reduce obesity including weight loss by energy restriction have disease risk reduction benefits, however, energy restriction alone often leads to the loss of muscle mass. Muscle is a very important tissues in the body particularly from a metabolic standpoint, thus, efforts to maintain it by promoting weight loss with the greatest ratio of fat:lean mass loss should be implemented. Also, bone health may be negatively affected by weight loss if hypoenergetic diets are suboptimal in calcium. Hence, the objective of this thesis was to determine how hypoenergetic diets varying in protein (amount and type) with exercise impacted the composition of weight lost and bone health in premenopausal, overweight and obese women. Ninety women were randomized to three groups (n=30/group): HiDairyPro, DairyPro and Control, differing in the quantity of total protein consumed (30%, 15% or 15% of energy, respectively) and the amount from dairy foods (high, moderate or low, respectively). Body composition was measured by DXA and fourier-transform near infrared spectroscopy (FT-NIR) at 0, 8 and 16 weeks, and visceral adipose tissue by MRI (<em>n</em>=39) at 0 and 16 weeks. Blood and urine samples were taken at 0 and 16 weeks. All groups lost similar body weight, but HiDairyPro lost significantly more total and visceral fat, and gained significantly more lean mass than Control (Chapter 2). HiDairyPro significantly improved bone health and vitamin D status compared to Control (Chapter 3). DXA and FT-NIR measured fat mass correlated and agreed well with each other (Chapter 4). Therefore, diet- and exercise-induced weight loss with higher protein and dairy promoted more favourable body composition changes and improved bone health versus diets with lower protein and no dairy. These data have strong implications for the design of weight loss programs to combat obesity.</p> / Doctor of Philosophy (PhD)