A method for delivering a large molecule to the brain includes administering the large molecule via an intermittent bolus regimen intrathecally to a subject at a level of C3 or above. A method for delivering a large molecule to the brain includes rostrally advancing a catheter in the intrathecal space of a subject until a delivery region of the catheter is located at a level of C3 or above and delivering the large molecule via the delivery region. Employing aspects of such methods, a method for altering eating behavior is described.