It seems that the alteration of lipid and carbohydrate metabolism because of exposure to pesticides and activation of PPARs is mainly due to an increase in the concentration of lipids, triglycerides, and cholesterol, which are directly related to the increase in the expression of PPARα and PPARγ and the genes activated by these receptors, thus linking them to the development of obesity. The gene discussed is PPARG; the disease is obesity due to melanocortin 4 receptor deficiency.