FADS1 and obesity due to melanocortin 4 receptor deficiency: In this study, using global, untargeted metabolomics and an HNF4α exon swap (α7HMZ) mouse model that happens to express low levels of the enzymes (FADS1, EPHX1, ACOX1/2, CYP2Cs) that metabolize LA (and ALA) into oxylipins, we show that lower levels of LA/ALA diols in the liver correlate with resistance to soybean oil-induced obesity, reinforcing our previous finding that elevated levels of hepatic oxylipins in WT livers correlate positively with obesity (7) (Fig. 10A).