Meal replacements on obesity and leptin: a systematic review and meta-analysis.

The global prevalence of obesity and overweight is a significant concern in the field of public health. Numerous interventional studies have been conducted to assess the possible meal replacements (MRs) effect on anthropometric indicators and indices and laboratory test that reflect obesity. However, there are no comprehensive results in this field. The study aim was to understand the possible effects of MRs on body weight, body mass index (BMI), fat mass, waist circumferences (WC), and leptin levels. A systematic search was conducted in five electronic databases in order to find randomized clinical trials (RCTs) that examined the possible MRs effect on obesity. Analyses were performed in R software, version 4.2.1. The random-effects model analysis was used to provide pooled mean difference and 95% confidence intervals (95% CI). Seventy studies were included. Body weight (WMD: -3.35 kg, 95% CI: -4.28 to -2.42), BMI (WMD: -1.12 kg/m2, 95% CI: -1.51 to -0.72), fat mass (WMD: -2.77 kg, 95% CI: -3.59 to -1.6), WC (WMD: -2.82 cm, 95% CI: -3.51 to -2.12) were significantly reduced after MRs compared to control. No significant effect was observed on leptin (WMD: -3.37 ng/ml, 95% CI: -8.23 to 1.49). Subgroup analyses indicated that impact of total MRs on anthropometric factors was greater in comparison to partial MRs. Considering other lifestyle factors, MRs can lead to anthropometric indicators and indices reduction.