The composition of the gut microbiome can be affected by environmental factors, such as diet. The Western dietary pattern is associated with microbiome dysbiosis and adverse health outcomes, including obesity and metabolic disorders. The objective of this study was to examine the effect of gut microbiota from lean or obese human donors on metabolism and weight gain in recipient mice fed one of three basal diets: 1) the standard AIN93G diet, which promotes rodent health; 2) the total Western diet (TWD), which mimics the American dietary pattern and promotes inflammation-associated colorectal carcinogenesis; and 3) a 45% high fat diet-induced obesity (DIO) diet, which promotes excessive weight gain and symptoms of metabolic syndrome. We hypothesized that fecal microbiome transfer (FMT)from obese human donors would lead to an obese phenotype with symptoms of metabolic syndrome in recipient mice, and that consumption of TWD or DIO diets would further exacerbate the metabolic syndrome phenotype. The experiment design consisted of two main factors: body type of the human donor (obese or lean) and experimental diet (AIN, DIO or TWD), which was fed to mice for 22 weeks. Prior to FMT, the resident gut microbiome in mice was depleted using an established broad spectrum antibiotic/antifugal oral dosing regimen. Interestingly, human donor body type did not significantly affect final body weight or body composition in recipient