An elastic bladder is provided that is in constant fluid communication with the expandable balloon portion of a gastric band in order to automatically and continuously adjust the gastric band. The fluid pressure between the bladder and the balloon portion of the gastric band automatically and continuously adjusts so that there is no lasting pressure differential between the bladder and the expandable balloon. As the level of restriction imparted by the gastric band on the stomach of the patient changes, fluid from the bladder automatically and substantially instantaneously flows to or from the expandable balloon portion of the gastric band thereby maintaining neutral fluid pressure equilibrium between the bladder and the balloon and automatically adjusting the band to the correct level of restriction to keep the patient in the optimum zone for weight loss.
