The gut microbiome and its role in obesity and metabolic disease

Obesity is a global health problem driven by the complex interplay between genetic, environmental and microbial factors. Over the last decade, evidence from animal models and human studies suggests that the trillions of bacteria in our gastrointestinal tract act as a metabolic organ and influence energy harvest, fat storage and systemic inflammation. This review describes how early‐life events shape the adult gut microbiota, how microbial composition differs in obesity and metabolic syndrome, and the mechanistic pathways particularly short‑chain fatty acids, bile acid signalling and immune crosstalk through which the microbiota may promote or protect against obesity. Finally, current and emerging therapeutic strategies, such as dietary modulation, probiotics, prebiotics, antibiotics and faecal microbiota transplantation, are discussed.