MICE ARE THE MOST COMMONLY USED MODEL ORGANISMS FOR MICROBIOME RESEARCH, YET IT IS NOT CLEAR THAT RELEVANT FINDINGS IN MICE ARE TRANSLATABLE TO HUMAN HEALTH. DIET INFLUENCES THE COMPOSITION AND METABOLIC ACTIVITY OF THE MICROBIOME, IN BOTH HUMANS AND MICE, YET LITTLE ATTENTION HAS BEEN PAID TO TRANSLATING DIETARY INTAKES BETWEEN THE TWO SPECIES. THIS IS ESPECIALLY TRUE FOR DIETARY FIBER. AMERICANS CONSUME, ON AVERAGE, 60% OF THE FIBER RECOMMENDED IN THE DIETARY GUIDELINES. DATA FROM PROSPECTIVE COHORT STUDIES HAS SUGGESTED THAT SUBOPTIMAL FIBER INTAKES PREDISPOSES INDIVIDUALS TO INCREASED GUT AND SYSTEMIC INFLAMMATION, METABOLIC DYSREGULATION, AND THE DEVELOPMENT OF CARDIOVASCULAR DISEASE AND TYPE 2 DIABETES. OUR LONG-TERM GOAL IS TO DETERMINE IF MICE CAN BE USED AS EFFECTIVE SURROGATES FOR MICROBIOTA STUDIES FOCUSED ON DIETARY FIBER, AND IF SO, TO IDENTIFY OPTIMUM FIBER PROFILES THAT ENHANCE METABOLIC HEALTH. OUR PRIMARY OBJECTIVE IS TO EVALUATE IF ADEQUATE HUMAN FIBER INTAKES, ALLOMETRICALLY SCALED TO RODENT DIETS, CAN PROTECT MICE AGAINST DEVELOPING INSULIN RESISTANCE WHEN FED A HIGH FAT DIET. IN HUMANS, FIBER INTAKE AT 100% OF THE RECOMMENDED LEVEL HAS BEEN SHOWN TO ALLEVIATE DIABETES SYMPTOMS AND THE EFFECT WAS MEDIATED VIA THE MICROBIOTA. THIS STUDY WILL ADDRESS A CLEAR KNOWLEDGE GAP REGARDING THE UTILITY OF MOUSE MODELS FOR MICROBIOTA RESEARCH.