Obesity is associated with an altered gut microbiota profile. Dietary fiber, food componentsbroken down by gut bacteria, beneficially shape the gut microbiota, and increasing daily fiberconsumption promotes weight loss in both obese rodents and humans. We recently analyzed theefficacy of both plant-based flours and fibers on improving metabolic homeostasis, and foundthat flours high in beta-glucan, and beta-glucan directly, along with oligofructose, are mosteffective at reducing adiposity and body weight in diet-induced obese rodents. Despite theknown interaction between dietary fiber and the gut microbiome, little is known about the exactmechanisms for how specific dietary fibers improve energy homeostasis. Our recent workhighlights a role for the small intestinal microbiota in metabolic homeostasis, an oftenoverlooked site of action, through both changes in specific bacteria, as well as gut derivedmetabolites. Based on our preliminary data, we will examine how dietary fiber can improvesmall intestinal nutrient sensing mechanisms that regulate food intake via a gut-brain axis, whichis dependent on changes in the small intestinal microbiome. We will identify specific smallintestinal bacteria that could act as potential probiotics. Additionally, we will examine how fiber-induced changes in the small intestinal microbiome alters bile acid homeostasis These aimsdirectly address the "Food and Human Health (3d)" section of the Food Safety, Nutrition, andHealth program area, as it examines the impact of food components and its metabolites on thegut microbiome to promote human health