The effect of probiotics on weight management in patients with severe obesity undergoing metabolic and bariatric surgery: a systematic review and meta-analysis

Although metabolic and bariatric surgery (MBS) remains an effective intervention for severe obesity, postoperative weight regain persists as a significant clinical challenge. Probiotics have emerged as a potential adjunct therapy to optimize outcomes, but their efficacy in weight management remains controversial. This meta-analysis evaluates the effect of probiotics supplementation on weight management in patients following MBS. A comprehensive search strategy was executed across four databases (PubMed, Embase, Scopus and Cochrane Library) from inception to April 10th, 2025. Inclusion criteria encompassed randomized controlled trials comparing probiotics with placebo in patients with severe obesity undergoing MBS. Primary outcomes including percent excess weight loss (%EWL), postoperative body mass index (BMI), and BMI reduction. Data were pooled using the random-effects model. A total of 13 trials included 693 patients were finally analyzed in the meta-analysis. Pooled analysis demonstrated no significant difference in %EWL (MD 0.39, 95% CI −1.90 to 2.68, I²=43%), postoperative BMI (MD 0.07, 95% CI −0.21 to 0.35, I²=26%), and BMI reduction (MD −0.05, 95% CI −0.53 to 0.44, I²=60%) between probiotics and control groups. Subgroup analyses stratified by surgery type, probiotic formulation and treatment duration similarly revealed no clinically meaningful effects. Current evidence does not support the routine use of probiotics for enhancing weight loss after MBS, regardless of surgical technique and treatment duration. Further large-scale trials standardizing strains, dosages, and outcome metrics are warranted.