Secondly, Jia et al., investigated the effects of coffee consumption on insulin resistance in mice fed a high fat diet known to induce obesity [15]. Mice were fed a high fat diet mixed with green coffee, caffeinated coffee, decaffeinated coffee, or no coffee for 9 weeks. Green coffee is made from unroasted coffee beans where the caffeinated and decaffeinated coffee used in the study were derived from roasted coffee beans. Each type of coffee attenuated the body weight gain by the high fat diet, without altering the food intake. Consumption of any type of coffee attenuated the high fat diet-induced insulin resistance, as evidenced by a greater decrease in blood glucose levels after insulin stimulation, however, only the green coffee group reached statistical significance. Consumption of any type of coffee tended to increase tyrosine phosphorylation of IRS-1 in skeletal muscle, but did not reach statistical significance.