Here the authors report that the heat shock proteins HSP70 and GRP78 are increased in the jejunum of rats on HFD, and their continuous infusion leads insulin resistance and NASH, while in rats on a high-fat diet infused with monoclonal antibodies against HSP70 and GRP78 these phenotypes are reversed. This evidence concerns the gene HSPA5 and metabolic dysfunction-associated steatohepatitis.