Currently, metabolic surgery (Laparoscopic Roux-en-Y gastric bypass, LRYGB) has an important role in the treatment of type 2 diabetic patients with obesity and should be recommended as an intervention in the management of obese patients with type 2 diabetes mellitus. For the success of bariatric surgery, effective meal management is essential. In the short term meal management, patient meals should be monitored to reduce the side effects after surgery (especially, vomiting). As the insulin sensitivity may be blunt due to stress or inflammation, proper energy intake should be assured, especially that of protein. In long term meal management, essential supplements such as vitamins and minerals should be taken, and healthy dietary life should be recommended to prevent the recurrence of diabetes and weight gain.