BACKGROUND: This study was aimed to investigate the level of satisfaction after introducing green whole grain mixed diet as a staple food and its effects on reduction in body weight and blood glucose level in patients with type 2 diabetes. METHODS: The enrolled subjects involved patients who had been receiving treatment for type 2 diabetes since their visit to the Diabetic center at Chungnam National University Hospital. A mixed diet that consisted of 30% green whole grains was introduced to these subjects as staple food for 12 weeks. Anthropometric measurements were taken, blood tests for glucose and lipid levels were conducted, and survey was done to assess the subjects' dietary habits before and after the green whole grain diet.and their level of satisfaction with the green whole grain diet. RESULTS: No significant changes in either average body weight or BMI were observed whereas a significant decrease in waist circumference (P = 0.01) was noted. However, the obese group (BMI > or = 25 kg/m2) in particular, showed a decrease in body weight (P = 0.012), significant decrease in both BMI (P = 0.013), and also in waist circumference (P < 0.01). Among the total subjects, 81.6% expressed high level of satisfaction with the mixed diet and were willing to consume the mixed diet consistently. CONCLUSION: A 12-week green whole grain mixed diet induced waist circumference reduction in patients with type 2 diabetes mellitus. Also, in obese diabetic patients, this mixed diet led to body weight reduction and improvement of abdominal obesity.