PYY and fatty liver disease: Fermentable fibers that serve as substrates for beneficial gut bacteria, leading to the production of short-chain fatty acids (SCFAs: butyrate, propionate, and acetate). SCFAs enhance gut hormone release (GLP-1 and PYY via FFAR receptors) and provide energy to enterocytes, strengthening the gut barrier. This reduces endotoxemia (LPS leakage) and liver inflammation. Also, fiber fermentation shifts microbiome composition (e.g., increases Bifidobacteria) and can reduce microbial choline conversion to TMA, mitigating fatty liver.