Previous studies in humans and animal models have shown that the 5-LOX/LT pathway and, more recently, the 12/15-lipoxygenase pathway are linked to the pathogenesis of obesity and its associated metabolic disorders [38,39], as well as to insulin resistance and fatty liver disease [40,41,42]. This evidence concerns the gene ALOX5 and obesity due to melanocortin 4 receptor deficiency.