The glycemic index is a dietary method used to promote weight loss and control insulin levels. The American Diabetes Association doesn't advocate this dietary regimen to promote diabetic control because it isn't based on evidence-based medicine or research. Other organizations, such as the European Association for the Study of Diabetes Nutrition Group recommends low glycemic foods as the carbohydrate of choice to help improve glucose control, according to Tori Irwin, a member of Glycemic Index, Ltd. When using the glycemic index to make food choices, keep certain considerations in mind for your meals and snacks.
Reference Range
Foods obtain their glycemic rating by how large of a glucose response you receive after eating a single serving of a food item. The basic principle of the glycemic index is the larger and more rapid the glucose response is to a food, the larger insulin output in an effort to bring your glucose level back down to pre-meal values. Low glycemic foods have a reference range under 50, medium glycemic is 51 to 70 and high glycemic is above 71.
High Glycemic Foods
When eating a high glycemic food, the University of Wisconsin Hospitals and Clinics recommends eating high glycemic foods in limited quantities and frequency. This can lessen the impact on your glucose level by decreasing the potential blood glucose release and insulin response. The glycemic index of a food changes based on your serving size, so the larger the portion size the bigger glucose response your body has to the food item. Another consideration is combining the high glycemic food with a low glycemic meal, especially if you are going to eat the high glycemic food close to your usual meal or snack time. Glycemic index of a food is altered when combined with foods that have a lower glycemic index. Fats and proteins don't contain carbohydrates, so the glycemic reference for these foods would be low and can potentially lower your glucose response to high glycemic foods.
Insulin Levels
Lowering your insulin response to foods is a guiding principle of the glycemic index. By lowering your glucose level, less insulin is produced, so fewer calories are stored as body fat versus being used to support your energy needs. Insulin impedes your fat cells from releasing fatty acids to use for energy. Lowering your glucose response to food and maintaining lower insulin levels promotes weight and fat loss.
Limitations
The glycemic index does not come without limitations and challenges. Food variability can affect how quickly or slowly food raises blood glucose levels. Also the main method of testing glucose response of food is using human subjects. Every person has their own chemical make up that can cause a food item to effect glucose levels differently. People are fed a 50 g portion size of a food item and the blood glucose levels achieved within 30 minutes of eating the food item are averaged together. Food processing, cooking methods, storage of the food items and ripeness can either raise or lower the glycemic effect, according to registered dietitian Sharon Palmer. No one eats a single food item in order to achieve the lowest possible insulin response, so relying on this method to control weight or manage a chronic disease has limitations. The main goal is to help you select foods with the highest fiber and nutritional value rather than completely eliminating certain foods based on a theorized number.
