Modulating the Gut Microbiome in Obesity: Interventions and Clinical Implications

Background: Obesity arises from complex interactions beyond energy imbalance, with the gut microbiome increasingly recognised as a key modulator of metabolic function in obesity. This narrative review examines microbiome-targeted interventions for obesity prevention and treatment. Objective: To synthesise evidence on diet, exercise, biotics (pre/pro/post/synbiotics) and faecal microbiota transplantation (FMT) as modulators of gut microbiota composition and function to improve body composition and metabolic health. Methods: A structured literature search of PubMed, Scopus and Web of Science (2015–2026) informed this narrative review, focusing on studies evaluating the role of the gut microbiome in obesity and the impact of microbiome-targeted interventions. Randomised controlled trials, systematic reviews, meta-analyses and key observational and preclinical studies were prioritised. Evidence was synthesised narratively. Results: Microbiome-targeted interventions including dietary modification, physical activity and biotic therapies demonstrate modest and variable effects on adiposity but may improve metabolic outcomes through mechanisms involving short-chain fatty acids (SCFA), inflammation and gut barrier function. High-fibre diets (e.g., resistant starch, Mediterranean) consistently enhance SCFA-producing taxa and reduce fat mass. Exercise induces modest microbiome shifts favouring beneficial bacteria such as Akkermansia / Bifidobacterium. Biotics (Lactobacillus / Bifidobacterium strains) yield small-moderate reductions in BMI / fat mass with next-generation strains (A. muciniphila, F. prausnitzii) showing promise in preclinical / human pilots. Evidence for FMT in obesity remains limited and inconsistent in humans. Mechanisms converge on energy harvesting, barrier integrity, endotoxemia reduction and GLP-1 / bile signalling. Conclusions: Microbiome modulation appears to complement lifestyle and therapeutic interventions but translation into clinical practice requires strain-specific, well-designed randomised controlled trials and longitudinal data. Personalised multiomics approaches offer future potential.