TNF and obesity due to melanocortin 4 receptor deficiency: In addition, elevated levels of fatty acids due to the increased lipolysis, high-fat diets, and hypoxia can result in ectopic fat deposition (as triglycerides and long-chain fatty acid forms) in skeletal muscles, liver, and β-cells; this increased ectopic fat deposition interferes with the normal functions of these tissues; for instance, the high levels of blood fatty acids and TNF-α occurring in obesity can induce insulin resistance [32–34].