Efficacy of High Carbohydrate versus High Protein Meal Replacements onWeight Reduction - A Randomized Controlled Trial

Abstract

Background: While formula diets as meal replacements are evident for weight loss, the macronutrient composition is still in the focus of interest. This study was designed to determine effects of a carbohydrate-riched meal replacement on weight loss and waist circumferences (WC) in comparison with a protein-riched meal replacement. Methods: Two groups (high carbohydrate formula diet (HC) and high protein formula diet (HP)) of 80 matched subjects each underwent a randomized parallel intervention trial for eight weeks followed by a 12-week follow-up. The intervention consisted of three phases: (1) week 1 and 2: total replacement of three meals, (2) week 3 and 4: replacement of two meals and (3) week 5 to 8: replacement of one meal. Measurements were taken at week 0, 2, 8, and 20. Results: After two weeks of total meal replacement, there was a significant (p<0.001) weight loss in both groups (HC: -4.0 ± 4.7 kg vs. HP: -4.3 ± 1.8 kg). After eight weeks, 66.2% of all subjects achieved a weight loss of 5% and more (HC: -8.5 ± 2.5%, p<0.001 vs. HP: -8.8 ± 2.8%, p<0.001), and 18.2% of the participants lost more than 10% of their initial body weight. Waist circumferences decreased from 105.9 ± 9.7 cm to 97.4 ± 8.4 cm (p<0.001) after eight weeks. During the follow up, further weight loss was observed in both groups. There were no significant differences between the HC and HP-group regarding changes in weight and WC. Conclusion: Both dietary intervention strategies had a similar effect on weight loss and WC reduction. In this short-term study macronutrient compositions of meal replacements are not crucial for the efficacy of formula diets. Trial registration: German Clinical Trials Register DRKS00005481.