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Changes in weight loss, body composition and cardiovascular disease risk after altering macronutrient distributions during a regular exercise program in obese women

Chad M Kerksick12, Jennifer Wismann-Bunn3, Donovan Fogt4, Ashli R Thomas5, Lem Taylor6, Bill I Campbell7, Colin D Wilborn6, Travis Harvey8, Mike D Roberts9, Paul La Bounty5, Melyn Galbreath10, Brandon Marcello11, Christopher J Rasmussen12 and Richard B Kreider12*

Author Affiliations

1 Applied Biochemistry and Molecular Physiology Laboratory, Health and Exercise Science Department, University of Oklahoma, Norman, OK 73019-6081, USA

2 Endocrinology and Diabetes Section, Department of Pediatrics, University of Oklahoma Health Sciences Center, Oklahoma City, OK 73104, USA

3 Department of Exercise Science, Campbell University, Buies Creek, NC 27502, USA

4 Laboratory for Exercise Biochemistry and Metabolism Health and Kinesiology Department, College of Education and Human Development, San Antonio, TX 78249, USA

5 Department of Health, Human Performance and Recreation, Baylor University, Waco, TX 76798-7313, USA

6 Human Performance Lab, Exercise & Sport Science Department, University of Mary-Hardin Baylor, Belton, TX 76513, USA

7 School of Physical Education & Exercise Science, University of South Florida, Tampa, FL 33620, USA

8 75th Ranger Regiment, Ranger Athlete Warrior, 6420 Dawson Loop, Fort Benning, GA 31905-4625, USA

9 Dept of Biomedical Sciences, University of Missouri-Columbia, 1600 E. Rollins, Columbia, MO 65211, USA

10 King Faisal Heart Institute, MBC 16, KFSH&RC, P.O. Box 3354, Riyadh, 11211, Saudi Arabia

11 Department of Athletics, Stanford University, Palo Alto, CA 94305, USA

12 Department of Health & Kinesiology, Texas A & M University, College Station, TX 77843, USA

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Nutrition Journal 2010, 9:59  doi:10.1186/1475-2891-9-59

Published: 22 November 2010

Abstract

Background

This study's purpose investigated the impact of different macronutrient distributions and varying caloric intakes along with regular exercise for metabolic and physiological changes related to weight loss.

Methods

One hundred forty-one sedentary, obese women (38.7 ± 8.0 yrs, 163.3 ± 6.9 cm, 93.2 ± 16.5 kg, 35.0 ± 6.2 kg•m-2, 44.8 ± 4.2% fat) were randomized to either no diet + no exercise control group (CON) a no diet + exercise control (ND), or one of four diet + exercise groups (high-energy diet [HED], very low carbohydrate, high protein diet [VLCHP], low carbohydrate, moderate protein diet [LCMP] and high carbohydrate, low protein [HCLP]) in addition to beginning a 3x•week-1 supervised resistance training program. After 0, 1, 10 and 14 weeks, all participants completed testing sessions which included anthropometric, body composition, energy expenditure, fasting blood samples, aerobic and muscular fitness assessments. Data were analyzed using repeated measures ANOVA with an alpha of 0.05 with LSD post-hoc analysis when appropriate.

Results

All dieting groups exhibited adequate compliance to their prescribed diet regimen as energy and macronutrient amounts and distributions were close to prescribed amounts. Those groups that followed a diet and exercise program reported significantly greater anthropometric (waist circumference and body mass) and body composition via DXA (fat mass and % fat) changes. Caloric restriction initially reduced energy expenditure, but successfully returned to baseline values after 10 weeks of dieting and exercising. Significant fitness improvements (aerobic capacity and maximal strength) occurred in all exercising groups. No significant changes occurred in lipid panel constituents, but serum insulin and HOMA-IR values decreased in the VLCHP group. Significant reductions in serum leptin occurred in all caloric restriction + exercise groups after 14 weeks, which were unchanged in other non-diet/non-exercise groups.

Conclusions

Overall and over the entire test period, all diet groups which restricted their caloric intake and exercised experienced similar responses to each other. Regular exercise and modest caloric restriction successfully promoted anthropometric and body composition improvements along with various markers of muscular fitness. Significant increases in relative energy expenditure and reductions in circulating leptin were found in response to all exercise and diet groups. Macronutrient distribution may impact circulating levels of insulin and overall ability to improve strength levels in obese women who follow regular exercise.