TNF and obesity due to melanocortin 4 receptor deficiency: Insulin resistance as seen in obesity and T2DM is associated with a chronic inflammatory state with increased tissue infiltration of immune cells in multiple organs and tissues such as adipose tissue, liver, skeletal muscle, pancreas, and brain, and people with or animal models of obesity and diabetes have elevated plasma levels of inflammatory mediators such as TNF-α, C-reactive protein, and FFAs [2,76,77].