RecruitingDevice studyEffect of Gastric Electrical Stimulation on Serum Insulin LevelsThe goal of this observational study is to determine how much effect turning the subject's Gastric Electrical Stimulator off for up to four hours will have on levels of insulin, C-peptide, GLP-1 and Glucose levels in patients with gastroparesis who have had a GES for at least three months, who are not taking diabetic prescribed exogenous insulin. EKG recordings will be made and analyzed for Heart Rate Variability and Power Spectral Analysis.