ABSTRACT
The glycemic index (GI) concept has been well reviewed [1], with a number of informative metaanalyses performed on the topic [2,3]. The benets of lower GI diets appear best established in the dietary management of type 2 diabetes [2]. However even in this situation the therapeutic advantage of lower GI diets has not always been demonstrated, for example in type 2 diabetes participants with low mean HbA1C levels (6.2%) who were controlled by diet alone [4]. There are also studies that weight loss may be promoted by low-glycemic-load (GI × carbohydrate) diets, especially in those with raised 30 min insulin levels [5]. However, not all studies have shown this effect consistently. The relation of high-GI diets to hyperinsulinemia and cancer promotion has also attracted attention. The concept is strong from the theoretical standpoint with type 2 diabetes being associated with more cancer [6,7] with the exception of prostate cancer and lymphoma [8]. Though the association of high-GI diets and increased cancer risk has been demonstrated in some cohort and case control studies [9-13], in others it has not [14]. The same applies to the association of low-GI diets and heart disease. For these and other reasons, the use of the GI concept has continued to be a matter of debate for 30 years. It is perhaps timely to review the concepts and issues that are relevant to this debate.
