The study measured the glycemic index (GI) values of common carbohydrate sources in Iran. Different types of bread and rice were tested on healthy adults to see how they affect blood sugar levels. Results showed that barley bread and brown rice have lower GI values compared to white rice and other types of bread commonly consumed in Iran. This suggests that choosing barley bread and brown rice over white rice and other bread types could help lower the overall GI values in the Iranian diet.