Objective: To determine the efficacy of a weight-loss diet using packaged portion-controlled entrees compared with a self-selected diet based on the U.S. Department of Agriculture Food Guide Pyramid (FGP) (United States Department of Agriculture, Center for Nutrition Policy and Promotion, Washington, DC; 1996).
Research methods and procedures: Sixty healthy women (BMI 26 to 40 kg/m(2); 24 to 60 years old) were randomized into two intervention groups for an 8-week parallel arm study. The portion-controlled group consumed two frozen entrees daily, plus additional food servings from the FGP. The self-selected diet group consumed a recommended number of servings from the FGP. Diets were designed to be the same in composition (55% carbohydrate, 25% protein, 20% fat) and energy level (1365 kcal). Each group met weekly to monitor compliance and take measures. Outcomes included weight, body composition by DXA, hip and waist circumference, blood pressure, fasting blood lipids, glucose, insulin, and C-reactive protein. Significant differences were assessed using repeated measures ANOVA.
Results: The portion-controlled group (n = 26) experienced greater decreases in weight (5.6 +/- 2.2 kg or 6.5% vs. 3.6 +/- 2.5 kg or 4.2%), fat mass (3.6 +/- 1.8 vs. 2.3 +/- 1.4 kg), total cholesterol (24.4 +/- 21.5 mg/dL or 12.4% vs. 13.0 +/- 13.9 mg/dL or 6.7%), and fasting insulin (-1.8 +/- 3.7 vs.+0.3 +/- 3.8 micro U/mL) than the self-selected diet group (n = 27) (p < 0.05).
Discussion: Consumption of portion-controlled entrees resulted in greater losses of weight and fat, thereby reducing cardiovascular disease risk. Accurate portion control is an important factor in weight loss success, and use of packaged entrees is an effective method of achieving this.