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Featured researches published by M Byrd.


Journal of The American Dietetic Association | 2011

A Structured Diet and Exercise Program Promotes Favorable Changes in Weight Loss, Body Composition, and Weight Maintenance

Richard B. Kreider; Monica C. Serra; Kristen M. Beavers; Jen Moreillon; Julie Kresta; M Byrd; Jonathan Oliver; Jean Gutierrez; Geoffrey M. Hudson; E Deike; Brian Shelmadine; Patricia Leeke; C Rasmussen; Mike Greenwood; Matthew B. Cooke; Chad M. Kerksick; J Campbell; Jeannemarie Beiseigel; Satya S. Jonnalagadda

BACKGROUND A number of diet and exercise programs purport to help promote and maintain weight loss. However, few studies have compared the efficacy of different methods. OBJECTIVE To determine whether adherence to a meal-replacement-based diet program (MRP) with encouragement to increase physical activity is as effective as following a more structured meal-plan-based diet and supervised exercise program (SDE) in sedentary obese women. DESIGN Randomized comparative effectiveness trial. PARTICIPANTS/SETTING From July 2007 to October 2008, 90 obese and apparently healthy women completed a 10-week university-based weight loss trial while 77 women from this cohort also completed a 24-week weight maintenance phase. INTERVENTION Participants were matched and randomized to participate in an MRP or SDE program. MAIN OUTCOME MEASURES Weight loss, health, and fitness-related data were assessed at 0 and 10 weeks on all subjects as well as at 14, 22, and 34 weeks on participants who completed the weight maintenance phase. STATISTICAL ANALYSES PERFORMED Data were analyzed by multivariate analysis of variance for repeated measures. RESULTS During the 10-week weight loss phase, moderate and vigorous physical activity levels were significantly higher in the SDE group with no differences observed between groups in daily energy intake. The SDE group lost more weight (-3.1 ± 3.7 vs -1.6 ± 2.5 kg; P = 0.03); fat mass (-2.3 ± 3.5 vs -0.9 ± 1.6 kg; P = 0.02); centimeters from the hips (-4.6 ± 7 vs -0.2 ± 6 cm; P = 0.002) and waist (-2.9 ± 6 vs -0.6 ± 5 cm; P = 0.05); and, experienced a greater increase in peak aerobic capacity than participants in the MRP group. During the 24-week maintenance phase, participants in the SDE group maintained greater moderate and vigorous physical activity levels, weight loss, fat loss, and saw greater improvement in maximal aerobic capacity and strength. CONCLUSIONS In sedentary and obese women, an SDE-based program appears to be more efficacious in promoting and maintaining weight loss and improvements in markers of health and fitness compared to an MRP type program with encouragement to increase physical activity.


The Physician and Sportsmedicine | 2011

A Carbohydrate-Restricted Diet during Resistance Training Promotes More Favorable Changes in Body Composition and Markers of Health in Obese Women with and without Insulin Resistance

Richard B. Kreider; Christopher Rasmussen; Chad M. Kerksick; Colin Wilborn; Lemuel W. Taylor; Bill Campbell; Teresa Magrans-Courtney; Donovan L. Fogt; Maria Pontes Ferreira; R Li; M Galbreath; M Iosia; Matthew B. Cooke; Monica C. Serra; Jean Gutierrez; M Byrd; Julie Kresta; S Simbo; Jonathan Oliver; Mike Greenwood

Abstract Objective: To determine whether sedentary obese women with elevated levels of homeostatic model assessment (HOMA) insulin resistance (ie, > 3.5) experience greater benefits from an exercise + higher-carbohydrate (HC) or carbohydrate-restricted weight loss program than women with lower HOMA levels. Methods: 221 women (age, 46.5 ± 12 years; body weight, 90.3 ± 16 kg; body mass index, 33.8 ± 5 kg/m2) participated in a 10-week supervised exercise and weight loss program. The fitness program involved 30 minutes of circuit-style resistance training 3 days per week. Subjects were prescribed low-fat (30%) isoenergetic diets that consisted of 1200 kcals per day for 1 week (phase 1) and 1600 kcals per day for 9 weeks (phase 2) with HC or higher protein (HP). Fasting blood samples, body composition, anthropometry, resting energy expenditure, and fitness measurements were obtained at 0 and 10 weeks. Subjects were retrospectively stratified into lower (LH) or higher (HH) than 3.5 HOMA groups. Data were analyzed by multivariate analysis of variance with repeated measures and are presented as mean ± standard deviation changes from baseline. Results: Baseline HOMA levels in the LH group were significantly lower than those in the HH group (LH, 0.6 ± 0.7; HH, 6.3 ± 3.4; P = 0.001). Diet and training significantly decreased body weight (−3.5 ± 3 kg), fat mass (−2.7 ± 3 kg), blood glucose (−3%), total cholesterol (−4.5%), low-density lipoproteins (−5%), triglycerides (−5.9%), systolic blood pressure (−2.6%), and waist circumference (−3.7%), while increasing peak aerobic capacity (7.3%). Subjects in the HP group experienced greater weight loss (−4.4 ± 3.6 kg vs −2.6 ± 2.9 kg), fat loss (−3.4 ± 2.7 kg vs −1.7 ± 2.0 kg), reductions in serum glucose (3% vs 2%), and decreases in serum leptin levels (−30.8% vs −10.8%) than those in the HC group. Participants in the HH (−14.1%) and HP-HH (−21.6%) groups observed the greatest reduction in serum blood glucose. Conclusion: A carbohydrate-restricted diet promoted more favorable changes in weight loss, fat loss, and markers of health in obese women who initiated an exercise program compared with a diet higher in carbohydrate. Additionally, obese women who initiated training and dieting with higher HOMA levels experienced greater reductions in blood glucose following an HP diet.


Journal of The International Society of Sports Nutrition | 2011

Comparative effectiveness of two popular weight loss programs in women II: metabolic markers

M Byrd; Michelle Mardock; Brittanie Lockard; Jonathan Oliver; S Simbo; Andrew R. Jagim; Julie Kresta; C Baetge; Peter Jung; M Koozehchian; D Khanna; Mike Greenwood; C Rasmussen; Richard B. Kreider

Background A number of commercial diet and exercise programs are promoted to help people lose weight and improve fitness. However, few studies have compared the effects of following different types of exercise and diet interventions on weight loss. The purpose of this study was to compare the efficacy of a more structured meal plan based diet intervention and supervised exercise program that included resistance-exercise to a traditional point based diet program with weekly counseling and encouragement to exercise. Methods Fifty-one sedentary women (35±8 yrs, 163±7 cm; 90±14 kg; 47±7% body fat, 34±5 kg/m 2 ) were randomized to participate in the Curves (C) or Weight Watchers (W) weight loss programs for 16-weeks. Participants in the C program were instructed to follow a 1,200 kcal/d diet for 1-week, 1,500 kcal/d diet for 3-weeks, and 2,000 kcals/d diet for 2-weeks, consisting of 30% carbohydrate, 45% protein, and 30% fat. Subjects repeated this diet for the 16-week period. Subjects also participated in the Curves circuit style resistance training program 3-days/week and were encouraged to walk at a brisk pace for 30-minutes on non-training days. This program involved performing 30-60 seconds of bi-directional hydraulic-based resistance exercise on 13 machines interspersed with 30-60 seconds of low-impact callisthenic or Zumba dance exercise. Participants in the W group followed the W pointbased diet program, received weekly counseling at a local W facility, and were encouraged to increase physical activity. Fasting blood samples were obtained at 0, 4, 10, & 16 weeks and analyzed by multivariate analysis of variance (MANOVA) with repeated measures for changes in triglycerides (TG), total cholesterol (CHL), low density lipoprotein cholesterol (LDL-c), high density lipoprotein cholesterol (HDL-c), the CHL:HDL-C ratio, and blood glucose. Data are presented as percent changes from baseline for the C and W groups, respectively, after 4, 10, and 16 weeks. Results


Journal of The International Society of Sports Nutrition | 2011

The effects of IQPLUS Focus on cognitive function, mood and endocrine response before and following acute exercise

Adam G Parker; Josh Gordon; Aaron Thornton; Allyn Byars; John R. Lubker; Michelle L. Bartlett; M Byrd; Jonathan Oliver; S Simbo; C Rasmussen; Mike Greenwood; Richard B. Kreider

BackgroundPhosphatidylserine (PS) is a phospholipid found in cell membranes of most animals and plants. PS has been shown to reduce stress and increase performance in runners, cyclists and golfers. The purpose of this study was to investigate the effects of a PS containing formulation on cognitive function, mood and endocrine response before and after intense resistance exercise.Methods18 lower body, resistance trained, college aged males ingested 14 days of supplement (IQPLUS Focus, providing 400 mg of soy-derived PS) and a Placebo (PL), in a randomized, double-blind, placebo controlled, cross-over manner. Following 14 days of supplementation, participants performed an acute bout of lower body resistance training. Mood (Profile of Mood States, POMS) and cognitive function (Serial Subtraction Test, SST) were measured prior to, 5 minutes after, and 60 minutes after exercise. Venous blood samples were collected prior to, and 5, 15, 25, 40 and 60 minutes after exercise. Blood samples were analyzed for plasma cortisol and testosterone. Data were analyzed using repeated measures ANOVA.ResultsPS supplementation significantly reduced the time needed for a correct calculation on the SST by 20% (reduced by 1.27 s per calculation; PL: 6.4 s, PS: 5.13 s; p = 0.001), and reduced the total amount of errors by 39% (PL: 1.28 + .69, PS: .78 + .27, p = 0.53), and increased the amount of correct calculations by 13% (PL: 22.1 + 2.24, PS: 24.9 + 1.52, p = 0.07) prior to or in response to exercise compared to PL. Following exercise, there was no difference in SST scores between PS and PL. There were no significant changes in regards to mood or endocrine response to exercise as a result of PS supplementation.ConclusionPS supplementation significantly increased cognitive function prior to exercise. Improved cognitive function could benefit athletes and non-athletes alike. PS did not appear to affect mood or endocrine response prior to or following resistance exercise.


Journal of The International Society of Sports Nutrition | 2011

Comparative effectiveness of two popular weight loss programs in women III: health and fitness markers

Jonathan Oliver; Michelle Mardock; Brittanie Lockard; M Byrd; S Simbo; Andrew R. Jagim; Julie Kresta; C Baetge; Peter Jung; M Koozehchian; Deepesch Khanna; Mike Greenwood; C Rasmussen; Richard B. Kreider

Background A number of commercial diet and exercise programs are promoted to help people lose weight and improve fitness. However, few studies have compared the effects of following different types of exercise and diet interventions on weight loss and/or changes in health and fitness markers. The purpose of this study was to compare the efficacy of a more structured meal plan based diet intervention and supervised exercise program that included resistance-exercise to a traditional point based diet program with weekly counseling and encouragement to increase physical activity.


Journal of The International Society of Sports Nutrition | 2011

Comparative effectiveness of two popular weight loss programs in women I: body composition and resting energy expenditure

Michelle Mardock; Brittanie Lockard; Jonathan Oliver; M Byrd; S Simbo; Andrew R. Jagim; Julie Kresta; C Baetge; Peter Jung; M Koozehchian; Deepesch Khanna; Mike Greenwood; C Rasmussen; Richard B. Kreider

Background A number of commercial diet and exercise programs are promoted to help people lose weight and improve fitness. However, few studies have compared the effects of following different types of exercise and diet interventions on weight loss. The purpose of this study was to compare the efficacy of a more structured meal plan based diet intervention and supervised exercise program to a traditional point based diet program with weekly counseling and encouragement to exercise.


Journal of The International Society of Sports Nutrition | 2013

Analysis of efficacy and cost effectiveness of popular weight loss and fitness programs

R Dalton; C Baetge; B Lockard; K Levers; Elfego Galvan; Andrew R. Jagim; S Simbo; M Byrd; Y Jung; Jonathan Oliver; M Koozehchian; D Khanna; B Sanchez; Julie Kresta; K Horrell; T Leopold; M Cho; S Springer; A Rivera; C Cerda; C Rasmussen; Richard B. Kreider

Background Obesity is associated with many negative health outcomes. Diet and exercise has been shown to reduce obesity and various other factors linked to poor health. One of the major concerns is the expense of diet and exercise programs. This study compared the cost effectiveness of four popular weight loss programs and controls in terms of weight loss success and outcomes. Methods


Journal of The International Society of Sports Nutrition | 2010

Effects of high carbohydrate or high protein energy-restricted diets combined with resistance-exercise on weight loss and markers of health in women with serum triglyceride levels above or below median values

Jonathan Oliver; Julie Kresta; M Byrd; Claire N. Canon; Michelle Mardock; S Simbo; Peter Jung; Brittanie Lockard; D Khanna; M Koozehchian; C Rasmussen; Chad M. Kerksick; Richard B. Kreider

Effects of high carbohydrate or high protein energy-restricted diets combined with resistanceexercise on weight loss and markers of health in women with serum triglyceride levels above or below median values Jonathan M Oliver, Julie Y Kresta, Mike Byrd, Claire Canon, Michelle Mardock, Sunday Simbo, Peter Jung, Brittanie Lockard, Deepesh Khanna, Majid Koozehchian, Chris Rasmussen, Chad Kerksick, Richard Kreider


Journal of The International Society of Sports Nutrition | 2013

Effects of immediate and delayed nutrient timing following resistance exercise on changes in mixed muscle fractional synthesis rate (FSR) in post-menopausal women participating in a weight loss program

M Byrd; S Simbo; Y Jung; B Sanchez; M Cho; Chang-Woock Lee; B Lockard; C Baetge; K Levers; Elfego Galvan; Andrew R. Jagim; Jonathan Oliver; R Dalton; B Bessire; K Horrell; T Leopold; M Koozehchian; D Khanna; Kevin L. Shimkus; W Gapinsky; M Perez; J Hart; Steven E. Riechman; James D. Fluckey; Mike Greenwood; C Rasmussen; Richard B. Kreider

Effects of immediate and delayed nutrient timing following resistance exercise on changes in mixed muscle fractional synthesis rate (FSR) in post-menopausal women participating in a weight loss program M Byrd, S Simbo, YP Jung, B Sanchez, M Cho, CW Lee, B Lockard, C Baetge, K Levers, E Galvan, A Jagim, JM Oliver, R Dalton, B Bessire, K Horrell, T Leopold, M Koozehchian, D Khanna, K Shimkus, W Gapinsky, M Perez, J Hart, S Riechman, J Fluckey, M Greenwood, C Rasmussen, R Kreider


Journal of The International Society of Sports Nutrition | 2013

Effects of exercise and diet-induced weight loss on markers of inflammation I: impact on body composition and markers of health and fitness

K Levers; S Simbo; B Lockard; C Baetge; Elfego Galvan; M Byrd; Y Jung; Andrew R. Jagim; Jonathan Oliver; M Koozehchian; R Dalton; D Khanna; B Sanchez; Julie Kresta; K Horrell; T Leopold; M Cho; S Springer; A Rivera; C Cerda; C Rasmussen; Richard B. Kreider

Background The purpose of this study was to determine the effects of participating in a resistance-exercise based circuit training program while adhering to a higher protein diet designed to preserve fat free mass (FFM) during weight loss on body composition and markers of health. Then, in a companion paper, determine if exercise and diet-induced weight loss affect markers of inflammation.

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