The typical western diet is high in fat and simple sugars but low in fiber. This leads to increased hunger, food consumption, and weight gain, along with detrimental shifts in the gut microbial community, coined the gut microbiota. Prebiotics, like oligofructose, have been shown to reduce food intake and adiposity in rodents and humans, but the mechanism is unknown. A recent study in rats, by the Duca Lab at the University of Arizona, found that the mechanism may include the small intestinal microbiota and the gut-brain axis. Two days of oligofructose supplementation reduced food intake in rats on a high-fat diet, and after 6 weeks, the rats also had reduced body weight and adiposity. Further tests revealed that oligofructose altered the small intestinal microbial community, increasing the abundance of Bifidobacterium in particular. This led to improved detection of fats by the small intestine during a meal and increased satiation signaling to the brain. Even just transplanting the small intestinal microbiota of rats with 3 days of oligofructose into naïve rats on a high-fat diet had similar effects, as did administering Bifidobacterium pseudolongum alone. More research is needed, but the results suggest that oligofructose improves nutrient sensing by rapidly altering the small intestinal microbiota and establish the small intestinal microbiota as a potential target to regulate food intake and treat obesity.