<b>Methods:</b> We performed a cross-sectional analysis in a random sample of 487 individuals (53.03 ± 13.71 years, 48.3% male) which were classified based on body mass index (</≥25 kg/m<sup>2</sup>) and insulin resistance (HOMA-IR cut-off value 2.5) as Insulin-Sensitive/Insulin-Resistant Normal Weight (ISNW/IRNW) and Insulin-Sensitive/Insulin-Resistant Obesity (ISO/IRO). The gene discussed is INS; the disease is obesity due to melanocortin 4 receptor deficiency.