Systems and methods are disclosed to stimulate gastrointestinal tissue to treat medical conditions such as eating disorders, gastroparesis, and gastric reflux. The invention uses electrical stimulation of the nerve, where vibrational energy from a source is received by an implanted device and converted to electrical energy and the converted electrical energy is used by implanted electrodes to stimulate the pre-determined gastrointestinal tissue site. The vibrational energy is generated by a controller-transmitter, which could be implanted or located externally. The vibrational energy is received by a receiver-stimulator, which could be located in the various regions on or around the gastrointestinal tissue that needs to be stimulated. The implantable receiver-stimulator stimulates different gastrointestinal tissue to provide the desired therapeutic benefit.