SOD2 and obesity due to melanocortin 4 receptor deficiency: Cellular oxidative stress is also affected by other host factors: (1) obesity, insulin resistance, and NAFLD increase cellular oxidants, (2) fatty liver increases lipid peroxidation, and (3) obesity, insulin resistance, and NAFLD are related to cellular antioxidation (e.g., SOD2, GPx1[23]) depletion of antioxidants.