The glycemic index (GI) method was developed a quarter century ago as a measurement tool for characterizing foods to assist diabetes patients in controlling postprandial glucose through diet. The method has inspired significant research on this approach to measuring the impact of available carbohydrates on human physiological response.

• All methods require careful scientific assessment for validity.
• A multilaboratory study demonstrated that the GI measurement purporting to differentiate one food from another is not reproducible from one eating occasion to the next and therefore does not differentiate foods.
• Extensive research on the GI method results attempting to show cause and effect relationships with health states has been conducted.
• Research results on GI-characterized foods have generally not shown significant relationship with health outcomes.
• The inability of the GI method to differentiate between foods on eating occasions leads to the conclusion that the food itself is a minor contributor to a given GI measurement, and therefore the GI method does not measure a meaningful property of a food.