Obesity risk was higher in inactive individuals homozygous to FTO rs9939609 compared to inactive individuals heterozygous to FTO rs9939609 (OR = 1.78, 95% CI 1.23–2.57; p = 0.002 and OR = 1.4, 95% CI 1–1.93; p = 0.04), respectively. Here, FTO is linked to obesity due to melanocortin 4 receptor deficiency.