The aim of this clinical study was to evaluate a practicable method to improve metabolic control and body weight in obese patients suffering from Type 2 diabetes. Eighteen overweight Type 2 diabetic patients received an outpatient psychoeducational group program over 1 year, which was centered on aspects of metabolic control in diabetes. This group was compared with 18 control patients who did not obtain any special psychoeducational training. There was a significant reduction of glycosylated hemoglobin and body weight over 1 year in the treatment group compared with the controls. In conclusion, 1 year of psychoeducational training of obese Type 2 diabetic patients significantly improved body weight and glycosylated hemoglobin. Implications are described for professional health care management of the disorder and aspects of the learning theory.