Synergistic Effects of Fu Brick Tea Extract and Millet on Antiobesity in High-Fat Diet-Fed Mice through Gut Microbiota Modulation and Activation of the Ffar2 – Gcg / Pyy Molecular Pathway

This study elucidates the antiobesity mechanism of the Fu brick tea extract–millet complex (FTE-M). FTE-M exhibited a dense and smooth microstructure, resulting in improved digestive properties compared with millet alone, including a reduced glycemic index and increased slowly digestible starch and resistant starch contents. In a 10-week high-fat diet mouse model, dietary supplementation with FTE-M inhibited small intestinal α-amylase activity, delayed starch digestion, and improved glucose and lipid metabolism while alleviating inflammation. FTE-M also modulated gut microbiota composition, normalized bile acid profiles, and enriched short-chain fatty acids (SCFAs)-producing bacteria, including Akkermansia, leading to a 2.49-fold increase in total SCFAs. Mechanistically, elevated SCFAs were associated with the activation of free fatty acid receptor 2 ( Ffar2 ) and increased expression of glucagon ( Gcg ) and peptide YY ( Pyy ), contributing to enhanced satiety. These findings highlight the potential of combining traditional millet with bioactive components to enhance metabolic functionality, providing a theoretical basis for developing starch-based antiobesity foods.