Recently, our collaborators, Vijay-Kumar et al [24] reported that TLR5 deficient mice also developed obesity, hyperlipidemia, and insulin resistance in response to high fat diet and the transfer of gut microbiota from TLR5 deficient mice to WT-germ-free mice conferred obesity, hyperlipidemia, and insulin resistance (features of metabolic syndrome) to the recipients suggesting that the gut microbiota mediate metabolic derangements associated with high fat diet. Here, TLR5 is linked to metabolic syndrome.