The human body contains ten times more bacteria than human cells, with hundreds of trillions of bacteria residing in the intestines alone. These microbiota play an important role in the extraction of energy and nutrients from food, and previous research suggests that changes in the gut microbial community may be associated with the development of diet‐induced obesity. The current study aims to observe shifts in the gut microbiomes of rats fed a junk‐food diet. Sprague Dawley rats were fed either a junk‐food diet or regular chow diet (n=12/group) for four weeks. During this period, rats were monitored for changes in the gut microbiota as well as anxiety‐like behaviors and cognitive function. Fecal samples were collected weekly and a portion of the slurried fecal samples were diluted, filtered, and plated on modified mTEC agar plates in order to obtain E. coli counts. Real‐time PCR will be used to analyze the microbial composition of the fecal samples as well as intestinal samples collected later in the study. A better understanding of the interactions between diet, obesity, the brain and the gut microbiome will potentially lead to new methods for the prevention and treatment of diet‐induced obesity.