The glycemic index gives an indication of the rate carbohydrates affect blood glucose (sugar) levels. The blood glucose level is measured after the ingestion of a carbohydrate, giving us the food’s glycemic index. This blood glucose value is compared to the blood glucose value acquired following an equal carbohydrate dose of glucose or white bread. Glucose is absorbed into the bloodstream faster than any other carbohydrate, and is thus given the value of 100. Other carbohydrates are given a number relative to glucose. Foods with low GI indices are released into the bloodstream at a slower rate than high GI foods, and create less of an insulin response.
Research appearing in the American Journal of Clinical Nutrition (2010; 92(3): 634-43) looked at the relationship between a diet with a high glycemic index and death from an inflammatory disease. The subjects of the study were 1245 men and 1490 postmenopausal women (the average age of the subjects was 49). A diet with a high glycemic index is usually high in refined sugars and starches. The researchers found that those whose diets were in the highest tertile of glycemic index had a 2.9-fold increase in the risk for death from an inflammatory disease when compared to those eating a diet with a low glycemic index.