AIM: To compare the effects of a Western diet (WD) or a Novel Gubra Amylin NASH (GAN) diet on body weight gain, and on the composition of the gut microbiome and metabolome, between the background mouse strain and male and female Mtarc1- or Mtarc2-KO mice. This evidence concerns the gene MTARC2 and metabolic dysfunction-associated steatohepatitis.