Background: Protein is suggested to be the nutrient providing the most satiety and is frequently used in meal-replacement products to achieve weight loss. Commercial products such as Herbalife high-protein (HP) products have been studied in various clinical trials, but controversy remains regarding their efficacy and safety.
Methods: We searched the PubMed, Center for Clinical and Translational Research (CCTR), and Google Scholar databases for randomized controlled trials of Herbalife HP products used as meal replacement (MR) published through July 2019 in peer-reviewed journals. We reviewed changes in efficacy and safety-related outcomes in treatment and control groups, and we estimated the pooled standardized mean difference (SMD) and corresponding 95% confidence intervals (CIs) with a DerSimonian and Laird random-effects method.
Results: By pooling data from nine identified studies (934 participants: 463 in treatment groups and 471 in control groups), we found that participants who consumed HP products experienced significantly larger decreases in body weight (SMD = -0.24; 95% CI: -0.37 to -0.10), body mass index (SMD = -0.31; 95% CI: -0.50 to -0.11), and fat mass (SMD = -0.37; 95% CI: -0.65 to -0.09) than did individuals consuming control diets. Concerning safety outcomes, the participants in the treatment group had a significantly larger decrease in aspartate aminotransferase (SMD = -0.23; 95% CI: -0.42 to -0.03). There were no significant between-group differences in alanine aminotransferase or creatinine. However, blood urea nitrogen levels increased in both groups, with a significantly larger increase in the treatment group (SMD = 0.53; 95% CI: 0.15 to 0.92).
Conclusions: Herbalife HP MR products appear effective and do not evidence significant risk in reducing body weight.
Keywords: fat-free mass; high-protein diet; meal replacement; waist circumference; weight loss.