The glycaemic index concept has more and more supporters all over the world. Many years will no doubt pass before the beneficial impact of a low glycaemic index diet in the prevention of heart diseases is fully confirmed, but we already know that the risk of heart diseases is lower when we use such a diet. Additionally, the diet is consistent with the other dietary changes necessary in the prevention of heart diseases. The data resulting from epidemiological and clinical investigations show that a low GI diet facilitates body mass reduction and an improved lipid profile. However, we still need further research to learn more about many processes which influence carbohydrate and lipid metabolism and the determination of the role of various genetic and environmental factors.