Obesity is known to present an inflammatory process of low grade, with elevated levels of cytokines such as interleukin 6 (IL-6), tumor necrosis factor alpha (TNF-α), and interleukin 1 beta (IL-1β), contributing to the pathogenesis of important disturbances of the obese condition, as insulin resistance and metabolic defects. Here, TNF is linked to obesity due to melanocortin 4 receptor deficiency.