In the present study, we used an experimental rat model of moderate (20%) maternal caloric restriction during pregnancy, which is known to be associated with alterations in hypothalamic circuitry that program a higher propensity to develop obesity in the offspring, particularly in males [6], to investigate whether oral supplementation with physiological doses of leptin throughout lactation is able to ameliorate or normalize developmental malprogramming of hypothalamus, which may be responsible, at least in part, for the adverse health outcomes later in life. The gene discussed is LEP; the disease is obesity due to melanocortin 4 receptor deficiency.