Background: Arguments have continued about Low Carbohydrate Diet (LCD) and Calorie Restriction (CR). Authors have reported clinical research of LCD and Morbus (M) value. Subjects and Methods: Subjects enrolled are 84 patients with Type 2 diabetes mellitus (T2DM), 60.9 ± 10.9 years. The protocol were as follows: 1) CR diet on day 1, 2 with 60% carbohydrates, and LCD on day 3-14 with 12% carbohydrates, 2) Daily profile of blood glucose 7 times a day on day 2 (CR) and day 4 (LCD), 3) urinary C-Peptide radioimmunoassay (u-CPR) excretion, 4) M value calculation, 5) investigation of these data with correlation. Results: Subjects were classified into 4 groups according to M value, which were .4–21, 23–66, 29–192, 200–728, respectively. HbA1c value was 6.2, 8.0, 7.8, 9.2 %, respectively. Blood glucose in median from day 2 to day 4 were 123 to 107 mg/dL, 164 to 130 mg/dL, 193 to 156 mg/dL, 277 to 201 mg/dL, respectively. M value in median from day 2 to 4 was 6.3 to 9, 41 to 7, 108 to 16, 367 to 88, respectively. u-CPR was 88 to 58, 53 to 35, 65 to 52, 74 to 64, respectively. There were significant correlations among among glucose, M value and u-CPR. Discussion and Conclusion: Average glucose, M value and u-CPR decreased remarkably on day 4. As average glucose and M value were higher, decrease degree were larger. These results suggested that carbohydrate in meal would influence glucose variability in T2DM. Our data would become basic data for pathophysiological analysis of glucose variability research in the future.