Agaricus blazei murill is a variety of mushroom purported to have anti-carcinogenic potential as well as liver enhancing characteristics. While previous research on rats cited a potential for increased natural killer cells and potential benefits for those with Hepatitis B, the dietary supplement may also potentially help fight obesity and other metabolic disorders such as insulin-resistance and low-grade inflammation. The present study aimed to test whether supplementation with Agaricus blazei murill (ABM) extract could have an effect on diet-induced obesity in rats. Rats were fed a control diet or high-fat diet (HF) which was either supplemented with Agaricus blazei Murill or not. The rats remained on the dietary regimen for 20 weeks. Compared to the control diet, the high fat diet induced weight gain and increased fat mass in the rats. In addition, HF rats developed hyperleptinemia and insulinemia as well as insulin resistance and glucose intolerance. And consistent with humans, the HF rats increased visceral adipose tissue which expressed biomarkers of inflammation. Interestingly, the rats that consumed the high fat diet and ABM supplement experienced a protective effect against body weight gain and all study related disorders. Their food intake remained significantly higher regardless of the ABM supplement. ABM supplementation induced an increase in both energy expenditure and locomotor activity which could partially explain its protective effect against diet-induced obesity. In addition, a decrease in pancreatic lipase activity was also observed in jejunum of ABM-treated rats suggesting a decrease in lipid absorption. According to researchers this data highlights a potential role for ABM to prevent body weight gain and related disorders in peripheral targets independent of food intake. (Obesity, 2012)