Effect of Total and Partial Meal Replacements on Factors Related to Glucose Metabolism: A Systematic Review and Meta-analysis of Randomized Controlled Trials

Although some evidence shows the beneficial effects of meal replacements (MRs) on glucose metabolism as one of the main factors of diabetes, there are still no comprehensive findings in this field. We investigated the effects of total and partial MRs on fasting blood sugar (FBS), insulin, glycated hemoglobin (HbA1c), and homeostatic model assessment for insulin resistance (HOMA-IR) in this comprehensive study and meta-analysis. To find pertinent randomized controlled trials (RCTs) up to March 2024, databases including PubMed/Medline, Web of Science, Scopus, and Embase were searched. This study included all RCTs investigating the effects of MRs on factors related to glucose metabolism. The pooled weighted mean difference (WMD) and 95% CIs were computed using the random-effects model. The findings from 52 studies indicated significant reductions in FBS (WMD: -3.10 mg/dL; 95% CI: -4.99, -1.20; P < .001), insulin (WMD: -1.79 μU/mL; 95% CI: -3.51, -0.08; P = .40), HOMA-IR (WMD: -0.86; 95% CI: -1.68, -0.04; P = .040), and HbA1c (WMD: -0.24%; 95% CI: -0.35%, -0.13%; P 50-years age group compared with those aged ≤50 years and also during interventions ≤24 weeks compared with >24 weeks. In conclusion, it appears that MRs, along with other lifestyle factors, can lead to significant improvements in glucose metabolism.