Reframing obesity through the gut microbiota: functional dysbiosis and metabolic disease.

Purpose Of Review Obesity and its metabolic complications remain major global health challenges. Beyond excess caloric intake, emerging evidence implicates diet-induced gut microbiota dysfunction as a modulator of metabolic homeostasis. This review examines recent advances in understanding how functional alterations of the gut microbiota contribute to obesity pathogenesis. Recent Findings Current data indicate that obesity is characterized less by specific microbial taxa and more by disruption of key microbial functions. Diet-induced dysbiosis alters short-chain fatty acid production, bile acid metabolism, tryptophan-derived signaling, and intestinal barrier integrity. These changes promote metabolic endotoxemia, impair enteroendocrine hormone secretion, and disrupt gut-brain and gut-liver communication, contributing to adipose tissue inflammation, hepatic steatosis, and insulin resistance. Experimental and clinical studies further suggest that microbiota-targeted interventions, including dietary fiber enrichment, prebiotics, synbiotics, and fecal microbiota transplantation, can partially restore microbial metabolic function and improve selected metabolic outcomes. Summary Obesity is increasingly conceptualized as a state of diet-driven functional gut microbiota disruption. Targeting microbial metabolic pathways rather than individual taxa may offer a promising adjunctive strategy to complement established therapies for obesity-related metabolic disease.