Diabetic nutritional therapy has been changing from Calorie Restriction (CR) to a Low Carbohydrate diet (LCD). Authors et al. have developed LCD medically and socially through the Japan LCD promotion association (JLCDPA), and proposed meal tolerance test (MTT) using LCD breakfast. For our research protocol, healthy subjects (n=8, M/F=4/4, BMI 20.5kg/m 2 ) received 75g oral glucose tolerance test (OGTT) and MTT, and changes in blood glucose and immunoreactive insulin (IRI) were measured. LCD meal included energy 307kcal, protein 13.8g, fat 23.9g, and carbohydrate 5.7g. The results from 0-30 min in average showed: i) 75gOGTT; 87.3-124.6mg/dL, 4.9-41.4μU/mL, ii) LCD; 90.3-84.3mg/dL, 5.4-12.2μU/mL, respectively. Decreased glucose may be from enough ability to secrete insulin to a glucose stimulus. These results would become reference data for future diabetic research.