An apparatus for controlling the food flow in the food passageway formed by the tissue wall of a patient's stomach comprises an implantable constriction device for gently constricting (i.e. without substantially hampering the blood circulation in the tissue wall) at least one portion of the tissue wall to influence the food flow in the food passageway, and a stimulation device for stimulating the wall portion of the tissue wall. A control device controls the stimulation device to stimulate the wall portion, as the constriction device constricts the wall portion, to cause contraction of the wall portion constricted by the constriction device to further influence the food flow in the food passageway. The apparatus can be used for treating obesity, with a low risk of injuring the stomach.
