Glycemic index: The glycemic index or GI is a ranking of foods on a scale from 0 to 100 according to the level to which they raise blood sugar levels subsequent to eating. The Glucose is given a relative number of 100 to give a baseline to which all others can be evaluated. For illustration, an apple has a glycemic index of 38 that is less than half that of glucose, however higher than soybeans (that contain a glycemic index of 18). Other common foods and their equivalent glycemic indices are dark rye bread (80), Corn Flakes (84), and bananas (54).