Prolonged feeding with a high-fat diet (HFD) or the disruption of leptin signalling in leptin-deficient (ob/ob) and leptin receptor-deficient (db/db) hyperphagic mice results in hepatic steatosis accompanied by obesity, IR, changes in lipid and glucose homoeostasis and oxidative stress [12,13]. This evidence concerns the gene LEP and obesity due to melanocortin 4 receptor deficiency.