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. 221 women (age, 46.5 ± 12 years; body weight, 90.3 ± 16 kg; body mass index, 33.8 ± 5 kg/m(2)) 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. 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. 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.
|Number of pages||14|
|Journal||Physician and Sportsmedicine|
|State||Published - May 2011|
Bibliographical noteFunding Information:
The authors would like to thank all of the doctoral, masters, and undergraduate students, and staff/colleagues at Baylor University and Texas A&M University who assisted with various aspects of this study. Although we cannot recognize the contributions on the author line, the effort and commitment has not been overlooked and is greatly appreciated. The authors would also like to thank Dr. Ron Wilson and Dr. J. P. Bramhall for providing medical supervision for this research. Curves® International (Waco, TX) provided funding for this project through an unrestricted research grant to Baylor University when the principal investigator and the Exercise and Sport Nutrition Laboratory were affiliated with that institution, and currently provides funding to Texas A&M University to conduct exercise-and nutrition-related research. Investigators independently collected, analyzed, and interpreted the results from this study and have no financial interests in the results of this study. Data from this study have been presented at the American College of Sports Medicine’s conference on Integrated Physiology of Exercise meeting in 2010. Publication of this study does not constitute an endorsement by any of the authors or their respective institutions. Richard B. Kreider, PhD served as principal investigator and contributed to the design of the study, study management, statistical analysis, manuscript preparation, and procurement of external funding. Remaining coauthors assisted in study coordination, data collection, data analysis, and/or manuscript preparation.
ASJC Scopus subject areas
- Orthopedics and Sports Medicine
- Physical Therapy, Sports Therapy and Rehabilitation