Gut microbiome-derived metabolites as predictors of bariatric surgery outcomes

Bariatric surgery remains the most effective treatment for severe obesity and obesity-associated metabolic disorders. However, substantial interindividual variability exists in postoperative weight loss and type 2 diabetes mellitus remission. Increasing evidence suggests that gut microbiome-derived metabolites may influence metabolic responses after bariatric surgery.

This narrative review synthesizes current evidence regarding the predictive role of gut microbiome-derived metabolites, particularly short-chain fatty acids, bile acids, and tryptophan-derived metabolites, in bariatric surgery outcomes.

A narrative literature review was conducted using PubMed, Web of Science, Embase, and ClinicalTrials.gov to identify studies published through May 2026. Studies examining associations between microbiome-derived metabolites and postoperative bariatric outcomes were reviewed and narratively synthesized.

Available evidence suggests that higher preoperative levels of beneficial microbiome-derived metabolites are associated with improved postoperative weight loss, enhanced insulin sensitivity, and greater likelihood of type 2 diabetes mellitus remission. Short-chain fatty acids appear to influence satiety and glucose metabolism, bile acids regulate metabolic signaling through farnesoid X receptor and Takeda G protein receptor 5 pathways, and tryptophan metabolites modulate inflammation and gut-brain communication. Nevertheless, findings remain inconsistent because of methodological heterogeneity, limited cohort sizes, and differences in metabolomic profiling techniques.

Gut microbiome-derived metabolites represent promising candidate biomarkers for predicting bariatric surgery outcomes. However, large-scale longitudinal studies using standardized metabolomic approaches are required before clinical implementation can be achieved.