In wild type (WT) and PKR-/- mice, blood glucose, insulin and lipid levels and the brain expression of the phosphorylated components of the metaflammasome—PKR, JNK, IRS1 and IKKbeta—were studied after the induction of obesity by a high fat diet (HFD). The gene discussed is MAPK8; the disease is obesity due to melanocortin 4 receptor deficiency.