This present study was intended for investigation of, first, circulating ghrelin levels (AcG, UnG and their ratio) in Obesity, second, their interdependencies with insulin resistance, third, their kinetic response after a glucose load during an oGTT and, fourth, their association with the FTO SNP rs8050136. The gene discussed is GHRL; the disease is obesity due to melanocortin 4 receptor deficiency.