If you're struggling with your weight and comparing popular diets, you might have come across something called the "glycemic index." The Zone, South Beach Diet, Atkins Diet, Nutrisystem and the Diabetic Exchange List are all based on choosing carbohydrates low on the glycemic index. In theory, foods low on the glycemic index have little effect on your blood sugar, which may help you lose weight and lower your risk of developing type 2 diabetes and heart disease.
Understanding the Glycemix Index
The glycemic index tells you the potential of any carbohydrate to raise your blood sugar level. Only carbohydrates raise glucose levels -- protein, fat and fiber all slow down the conversion of food into glucose. Pure glucose is rated 100 on the glycemic index, or GI, and all foods are compared to glucose. The lower the score of any food, the less effect it has on your blood sugar level.
How Foods are Tested
Australia's Sydney University GI Research Service, or SUGiRS, is the official testing center for the glycemic index. To test any food, a group of at least 10 healthy adults are given 50 g of pure glucose. In the following two hours, their blood sugar levels are monitored at specific timed intervals. A few days later, the same group of people are given 50 g of carbohydrates of the test food and have their blood sugar levels tested at the same timed intervals. The difference in blood sugar levels between the test food and the pure glucose is calculated for each individual and then averaged together to produce the final GI score.
Glycemic Index Categories
Foods that score below a 55 on the glycemic index are considered "low-GI" foods. Most vegetables, fruits, excluding dried fruits because of their concentrated natural sugar, and a few whole grains, such as rice and barley, are low-GI foods. Diets based on the GI recommend that most carbs consumed are low-GI carbs. Medium-GI foods score between 55 and 69 and include most breads, cold breakfast cereals and starchy root vegetables. High-GI foods, ranked 70 and above, include very sugary foods like jelly beans and corn chips.
Using the Glycemic Index
The glycemic index is a great guideline for making healthy choices, but it isn't perfect. Because fat, protein and fiber slow down the absorption of sugar into your bloodstream, low-GI foods may be high in fat. High-fat chocolate candy may score low on the glycemic index -- a Snickers bar is lower on the GI than an orange and Peanut M&Ms are lower than an apple. And nutrient-dense fruits and vegetables that contain natural sugars may score very high on the GI; watermelon scores higher than macaroni and cheese, parsnips score higher than a doughnut and dates score 103 -- higher than pure glucose. Use the glycemic index as a tool to help you make healthier choices, but use your common sense to choose foods rich in the vitamins and minerals your body needs to look good and feel even better.
