What is a High Glycemic Index?

A high glycemic index is a nutritional indicator which denotes a large concentration of sugar in a food and the strong potential for that food to severely affect blood sugar generally within three hours of eating. The root word “glyco” means sugar. A glycemic index is a sugar scale which ranks foods according to their carbohydrate content. Simple carbohydrates generally score high on the sugar scale and are ranked as high-glycemic index foods, while vegetables typically rank the lowest because they have little sugar and generally do not cause great shifts in blood sugar. Fruits can have a moderate impact on blood sugar and often rank as medium- or low-glycemic index snacks.

Complications related to diabetes necessitated the original glycemic index, which was created by a Canadian doctor in 1981 to guide sugar-sensitive diabetics who suffered from great swings in blood sugar and the related anxiety, lethargy, and headaches that excess carbohydrates can cause. Some sufferers even experienced comas. The high glycemic index, however, has become a coveted staple in areas beyond medical circles; many health-conscious individuals use the indicator on a daily basis to balance sugar intake with protein and vegetables. Loyalists to diet plans like the high-protein Atkins diet also gravitate to glycemic indexes to minimize carbs. Bodybuilders and athletes might rely on a high glycemic index to choose high-quality, sugar-packed foods before a major workout, marathon, or demanding competition so they can have long-lasting energy.

Foods are arranged from high to low on the glycemic index scale of 100. Those rated at a glycemic level of zero have absolutely no sugar, such as meats and fish. Low-glycemic index foods are frequently encouraged by dieticians and include dairy, vegetables and most fruits, which rank at level 55 or below on the index scale. Spinach, apples, and milk are some examples of low-glycemic index foods. Index levels between 56 and 69 indicate medium-glycemic index foods; they include white potatoes, corn chips, and oatmeal.

Simple carbohydrates, like white bread, and foods with sugar or corn syrup added, like most breakfast cereals, rank between levels 70 and 100 on the glycemic scale and are considered high-glycemic index foods. Aside from meats, nearly all foods contain some measure of sugar. A few surprises are revealed through the index; for example, watermelon, at level 72, is a high-glycemic index food similar to French fries, which rank at level 75. The benefit of using a glycemic index is that those who are sensitive to sugar can choose to combine low-glycemic index foods with high-glycemic index ones to meet cravings and still stabilize blood sugar. Glycemic indexes are available in nutrition books, health magazines, and online.