** AWARDS ISSUED PRIOR TO JANUARY 20, 2025, WERE FUNDED UNDER PREVIOUS ADMINISTRATIONS AND MAY NOT REFLECT THE PRIORITIES AND POLICIES OF THE CURRENT ADMINISTRATION.** THE PREVALENCE OF OBESITY AND TYPE 2 DIABETES HAS INCREASED DRAMATICALLY OVER THE LAST 40 YEARS, EMPHASIZING THE NEED TO INVESTIGATE THEIR ETIOLOGY AND DEVELOP NEW THERAPEUTICS FOR TARGETING METABOLIC DISEASE. OBESITY IS INFLUENCED BY OVERCONSUMPTION OF THE WESTERN DIET, WHICH IS HIGH IN FAT AND SUGAR AND LOW IN FIBER. THE GUT MICROBIOTA COMPOSITION IS LARGELY SHAPED BY DIET, SUGGESTING THAT TARGETING THE GUT MICROBIOTA THROUGH DIETARY INTERVENTION CAN BE A POTENTIAL THERAPEUTIC APPROACH FOR METABOLIC DISEASE. HOWEVER, HOW SHIFTS IN THE GUT MICROBIOTA FROM A WESTERN DIET IMPACT THE DEVELOPMENT OF OBESITY IS STILL LARGELY UNKNOWN.MY PRELIMINARY DATA DEMONSTRATE THAT OLIGOFRUCTOSE (OFS) OR BETA-GLUCAN SUPPLEMENTATION INTO A HIGH-FAT DIET (HFD) SIGNIFICANTLY REDUCES BODY WEIGHT AND ADIPOSITY AND LOWER BLOOD GLUCOSE LEVELS COMPARED TO SEVERAL OTHER PLANT-DERIVED FIBERS. ADDITIONALLY, OUR LAB HAS DEMONSTRATED THAT OFS SUPPLEMENTATION IN HF-FED RODENTS INCREASES SMALL INTESTINAL BACTERIAL ABUNDANCE OF ALLOBACULUM, HOWEVER, ITS ROLE IN METABOLIC HOMEOSTASIS IS COMPLETELY UNKNOWN. THEREFORE, I HYPOTHESIZE THAT BETA-GLUCAN AND OLIGOFRUCTOSE SUPPLEMENTATION IN A HFD IMPROVES METABOLIC HOMEOSTASIS VIA INCREASE IN ABUNDANCE OF BENEFICIAL BACTERIA IN THE GUT, SPECIFICALLY ALLOBACULUM.THUS, THIS PROPOSAL WILL 1) DETERMINE THE IMPACT OF VARIOUS DOSAGES OF BETA-GLUCAN AND OLIGOFRUCTOSE ON METABOLIC HOMEOSTASIS, 2) DETERMINE THE ROLE OF THE GUT MICROBIOTA IN PLANT-BASED FIBERS' EFFECT ON METABOLIC HOMEOSTASIS, AND 3) DETERMINE THE IMPACT OF A POTENTIAL PROBIOTIC ALLOBACULUM ON METABOLIC HOMEOSTASIS. A BETTER UNDERSTANDING OF THE IMPACT OF PLANT-BASED FIBER ON ALTERING THE GUT MICROBIOTA TO IMPROVE METABOLIC HOMEOSTASIS PROVIDES A POTENTIAL TREATMENT OPTION FOR OBESITY AND OTHER METABOLIC-RELATED CONDITIONS IN HUMANS AND PROVIDES THE AGRICULTURAL STAKEHOLDERS WITH GREATER KNOWLEDGE AS TO WHICH PLANTS CAN HAVE THE GREATEST IMPACT ON HUMAN HEALTH.