Effects of Intermittent Dieting During Resistance Training in Women II: Health Markers

Abstract

Dieting has been reported to reduce resting energy expenditure thereby increasing the prevalence of weight gain after weight loss. Intermittent dieting during a weight loss and exercise program may help minimize these adverse effects. PURPOSE: To examine the efficacy of diet cycling with varying macronutrient diet compositions during an exercise and weight loss program on markers of weight loss, health, and fitness. METHODS: 43 overweight and sedentary women (35±8 yr; 89±18 kg; 43±4% fat, 33±6 kg/m2) were assigned to a high carbohydrate (HC, n=23) or high protein (HP, n=20) diet group. During the first 30-days, subjects consumed 1,200 kcals/d for 1-wk followed by ingesting 1,500 kcals/d for 3-wks. Subjects then followed a 2,200 kcals/d maintenance diet for 4-wks before repeating the 30-day diet. Diets were 45:30:25% or 30:45:25% carbohydrate, protein and fat for the HC and HP groups, respectively. Subjects also participated in the Curves™ circuit training program 3-d/wk and walked briskly for 30-min 3-d/wk. Data were analyzed by MANOVA with repeated measures and are presented as means ± SD changes from baseline after 1, 2, 3, 4, and 5 months, respectively. RESULTS: Training and dieting significantly decreased resting systolic blood pressure (-1.0±8, -2.0±10, -1.5±10, -3.6±9, -3.7±7%, p=0.002), circumference of the waist (-4.1±6, -5.1±5, -5.6±6, -5.9±6, -5.0±7%, p=0.001) and hips (-1.1±4, -1.6±4, -1.7±4, -2.1±5, -2.8±6%, p=0.002), the waist to hip ratio (-2.9±6, -3.5±6, -3.9±6, -3.6±7, -2.1±7%, p=0.05), and serum TG levels (-3.6±38, -9.12±32, -13.6±29, -9.9±28, -10.5±37, p=0.02). Total cholesterol and LDL levels also declined, but these changes were not significantly different. There were no significant changes in resting heart rate, diastolic blood pressure, glucose or HDL levels. No significant differences were observed between diet groups. CONCLUSION: Short-term diet cycling during a weight loss and exercise program may be an effective way to promote changes in waist and hip circumference while markedly reducing TG levels. In addition, no significant differences were observed between diets on health markers when diets were 45:30:25% or 30:45:25% carbohydrate, protein, and fat, respectively. Supported by Curves International, Waco TX.