Created by researchers at the University of Sydney in Australia, the Glycemic Index, or GI, ranks carbohydrate-containing foods by how quickly you digest them and convert them into glucose, your body's main form of energy. This tool can help people with diabetes determine the best carbohydrates to eat to control their blood sugar levels, avoiding spikes and crashes that come from consuming too many refined foods and simple sugars. The best diet for diabetes consists of low GI foods.
Diabetes and Blood Sugar
Diabetes is a metabolic disorder in which the body either cannot produce insulin or produces too little. Insulin is a hormone manufactured by the pancreas, necessary for the metabolizing of carbohydrates into glucose. In people who do not have diabetes, the pancreas creates just enough insulin to process food into glucose, which feeds the body's cells and fuels its processes. In diabetics, however, a dangerous level of glucose accumulates in the bloodstream and is eventually eliminated in the urine, depriving the body of its main energy source. Unprocessed glucose may also contribute to complications of diabetes, which may include diseases of the heart, eyes and kidneys.
How the GI Works for Diabetics
Carbohydrates are macronutrients necessary for fueling the body's many functions, yet not all carbs are good for you. Diabetics, in particular, must be careful about the types and amounts of carbohydrates they consume to control their blood sugar levels and slow the onset of some of the complications of the disease. The GI ranks carbohydrate-containing foods -- which include legumes and beans, fruits, vegetables, whole and refined grains, processed foods and sugars -- on a scale of 0 to 100, according to how quickly your body can digest them. Foods rated under 55 are low glycemic, while those over 55 are high glycemic. Animal proteins and fats have little effect on blood sugar and are not ranked on the GI.
Benefits of Low GI Foods
Your body digests low GI foods slowly, creating a steady flow of glucose as fuel for the cells and preventing fluctuations in blood sugar levels that can lead to dizziness, confusion and other problems. For diabetics, a diet of low GI foods may also help prevent complications of the disease. According to the American Diabetes Association, a study of 1,441 people with type 1 diabetes, called the Diabetes Control and Complications Trial, DCCT, found that those who kept blood sugar levels low cut their risk of complications such as eye and kidney disease. In addition, those who already had these complications did not see their symptoms worsen.
Types of Low GI Foods
The best glycemic diet for diabetes is rich in whole foods rather than processed and refined foods, which include snacks and sugary desserts and cereals. Whole foods such as legumes and fresh produce are low on the GI scale. For example, kidney beans, lentils, peas and soybeans are among the beans and legumes with the lowest GI ratings. Many vegetables rate lower than 20 on the GI, including asparagus, bell peppers, broccoli, cabbage, celery, eggplant, green beans, lettuce, mushrooms, spinach and zucchini. The lowest GI fruits include cherries, apples, oranges, peaches and pears. Among grains, oatmeal, oat bran, stoneground whole wheat and sourdough have the lowest ratings. Low-fat yogurt is also low GI.
References
- National Diabetes Information Clearinghouse; Diabetes Overview; November 2008
- American Diabetes Association: Tight Diabetes Control
- "The Encyclopedia of Healing Foods"; Michael Murray, ND, and Joseph Pizzorno, ND; 2005
- The Glycemic Index: What Is the Glycemic Index?
