Several studies showed that circulating levels of leptin are highly related to percentage of body fat in humans suffering from obesity and normal body weight individuals; increased size of adipocytes due to accumulation of triglyceride induces an increase of leptin as an adaptive response signaling control of energy balance to the central nervous system (CNS) (Rosenbaum and Leibel, 1999; Ahima et al., 2000; Schwartz et al., 2000; Hafizuallah, 2006; Myers et al., 2009). This evidence concerns the gene LEP and obesity due to melanocortin 4 receptor deficiency.