Objective The aim of this study was to determine serum glucose, insulin and lipid levels in response to two different types of traditional breakfasts, one with a low glycaemic index (meal 1) and the other with a high glycaemic index (meal 2) that were prepared under supervision of a research dietitian and given to exogeneous obese adolescents.

Methods Ten boys and 10 girls with a mean age of 12.5 ± 1.35 years were recruited to the study. Two different traditional meals were given after 12-h fasting on different days. Venous blood samples were taken from the subjects for glucose at the beginning of the study and at 30, 60 and 120 minutes after consumption of meals. C-peptide, insulin and lipid profiles were determined at 60th minute after each meal.

Results Blood glucose values after meal 2 were higher compared with the consumption of meal 1. However, there was no significant difference among meals in terms of blood glucose levels. The increase in C-peptide and insulin values after meal 1 and meal 2 was compatible with previous data. Consumption of meal 2 caused a remarkable increase in insulin, C-peptide values, but the only significant difference between the two meals was in C-peptide values, being higher in those after meal 2.

Conclusions Our findings are similar to previous reports, which have shown that the consumption of high glycaemic index foods may cause hyperglycaemia and lead to obesity. However, our study was a 2-h long study, which limits its value, therefore we conclude that larger and longer studies are required in order to determine the metabolic effects of glycaemic index.