APOA4 and APOC3 apolipoproteins were increased in the plasma of obese rats and four apolipoproteins were elevated in the heart (A1, APOA4, APOC3, and E), suggesting the high vulnerability of cardiac tissue toward the lipidomic changes accompanying diet-induced obesity. The gene discussed is APOC3; the disease is obesity due to melanocortin 4 receptor deficiency.