The glycemic index of a starchy food is a measure of its digestibility, based on the extent to which it raises the blood concentration of glucose compared with an equivalent amount of glucose or a reference food such as white bread or boiled rice. Eating foods with low glycemic index will result in lower glucose levels after meals. Low glycemic index foods have values of 55 or less and include many fruits (apples, oranges) and vegetables, grainy breads, pasta, legumes, milk, and yoghu. High glycemic index foods have values of 70 and over and include baked potato, white bread, and most white rice. Glycemic index is lowered by the presence of fats and protein when the food is consumed in a mixed meal. Cooking methods can also affect the glycemic index--thus mashed potatoes have a higher glycemic index than baked potato. Ref: German M.S. (2011). Chapter 17. Pancreatic Hormones and Diabetes Mellitus. In D.G. Gardner, D. Shoback (Eds), Greenspan's Basic & Clinical Endocrinology, 9e.