OBESITY IS ASSOCIATED WITH AN ALTERED GUT MICROBIOTA PROFILE. DIETARY FIBER, FOOD COMPONENTS BROKEN DOWN BY GUT BACTERIA, BENEFICIALLY SHAPE THE GUT MICROBIOTA, AND INCREASING DAILY FIBER CONSUMPTION PROMOTES WEIGHT LOSS IN BOTH OBESE RODENTS AND HUMANS. WE RECENTLY ANALYZED THE EFFICACY OF BOTH PLANT-BASED FLOURS AND FIBERS ON IMPROVING METABOLIC HOMEOSTASIS, AND FOUND THAT FLOURS HIGH IN BETA-GLUCAN, AND BETA-GLUCAN DIRECTLY, ALONG WITH OLIGOFRUCTOSE, ARE MOST EFFECTIVE AT REDUCING ADIPOSITY AND BODY WEIGHT IN DIET-INDUCED OBESE RODENTS. DESPITE THE KNOWN INTERACTION BETWEEN DIETARY FIBER AND THE GUT MICROBIOME, LITTLE IS KNOWN ABOUT THE EXACT MECHANISMS FOR HOW SPECIFIC DIETARY FIBERS IMPROVE ENERGY HOMEOSTASIS. OUR RECENT WORK HIGHLIGHTS A ROLE FOR THE SMALL INTESTINAL MICROBIOTA IN METABOLIC HOMEOSTASIS, AN OFTEN OVERLOOKED SITE OF ACTION, THROUGH BOTH CHANGES IN SPECIFIC BACTERIA, AS WELL AS GUT DERIVED METABOLITES. BASED ON OUR PRELIMINARY DATA, WE WILL EXAMINE HOW DIETARY FIBER CAN IMPROVE SMALL INTESTINAL NUTRIENT SENSING MECHANISMS THAT REGULATE FOOD INTAKE VIA A GUT-BRAIN AXIS, WHICH IS DEPENDENT ON CHANGES IN THE SMALL INTESTINAL MICROBIOME. WE WILL IDENTIFY SPECIFIC SMALL INTESTINAL BACTERIA THAT COULD ACT AS POTENTIAL PROBIOTICS. ADDITIONALLY, WE WILL EXAMINE HOW FIBERINDUCED CHANGES IN THE SMALL INTESTINAL MICROBIOME ALTERS BILE ACID HOMEOSTASIS THESE AIMS DIRECTLY ADDRESS THE FOOD AND HUMAN HEALTH (3D) SECTION OF THE FOOD SAFETY, NUTRITION, AND HEALTH PROGRAM AREA, AS IT EXAMINES THE IMPACT OF FOOD COMPONENTS AND ITS METABOLITES ON THE GUT MICROBIOME TO PROMOTE HUMAN HEALTH