Food glycemic index, as given in glycemic index tables, is a significant determinant of glycemic responses elicited by composite breakfast meals.

Background: Recent studies have concluded that the carbohydrate content and glycemic index (GI) of individual foods do not predict the glycemic and insulinemic effects of mixed meals. We hypothesized that these conclusions may be unwarranted because of methodologic considerations.

Objective: The aim was to ascertain whether the GI and carbohydrate content of individual foods influence glucose and insulin responses elicited by realistic mixed meals in normal subjects.

Glycemic load and chronic disease.

The glycemic index (GI) has proven to be a useful nutritional concept, providing new insights into the relationship between foods and chronic disease. Observational studies suggest that diets with a high glycemic load (GI x carbohydrate content) are independently associated with increased risk of type 2 diabetes and cardiovascular disease. Postprandial hyperglycemia plays a direct pathogenic role in the disease process.

Glycemic index and obesity.

Although weight loss can be achieved by any means of energy restriction, current dietary guidelines have not prevented weight regain or population-level increases in obesity and overweight. Many high-carbohydrate, low-fat diets may be counterproductive to weight control because they markedly increase postprandial hyperglycemia and hyperinsulinemia. Many high-carbohydrate foods common to Western diets produce a high glycemic response [high-glycemic-index (GI) foods], promoting postprandial carbohydrate oxidation at the expense of fat oxidation, thus altering fuel partitioning in a way that may be conducive to body fat gain.

International table of glycemic index and glycemic load values: 2002.

Reliable tables of glycemic index (GI) compiled from the scientific literature are instrumental in improving the quality of research examining the relation between GI, glycemic load, and health. The GI has proven to be a more useful nutritional concept than is the chemical classification of carbohydrate (as simple or complex, as sugars or starches, or as available or unavailable), permitting new insights into the relation between the physiologic effects of carbohydrate-rich foods and health. Several prospective observational studies have shown that the chronic consumption of a diet with a high glycemic load (GI x dietary carbohydrate content) is independently associated with an increased risk of developing type 2 diabetes, cardiovascular disease, and certain cancers.