Methods and systems for treating patients suffering from eating disorders, e.g. obesity, through the dispensation of a drug by an implantable infusion pump (IIP) delivering drug into the cerebral spinal fluid (CSF) at a site of the intrathecal space in amounts and at times effective to suppress the patient's appetite through interaction of the drug transported through the CSF with receptors in the brain. Delivery of a programmed drug dosage is preferably by one of time-out of programmed time(s) of day, a command received from the patient, or a trigger signal developed from a sensed GI tract signal accompanying peristalsis.