The glycemic food index is based on the idea that different types of carbohydrates affect your blood sugar levels differently. The goal of the glycemic food index is to choose foods that keep your blood sugar levels steady, as to avoid rapid increases or decreases that can be harmful for a diabetic.
Physiology
When you consume carbohydrates, your body breaks them down into a simple sugar called glucose. Glucose travels through your digestive system until it reaches the small intestine, where it is deposited into your bloodstream. Once glucose enters your bloodstream, the pancreas releases a hormone called insulin, which binds to glucose and carries it to every one of your cells. The cells utilize this glucose for energy.
Those who are diabetic have some type of disruption in this process. In type 1 diabetes, the pancreas cannot produce enough insulin to carry glucose to your cells. In type 2 diabetes, the pancreas is able to produce insulin, but the cells cannot utilize it correctly. As a result, both types of diabetes are characterized by high levels of glucose in the bloodstream.
Diet Basics
The theory behind the glycemic index diet is that not all carbohydrates are "created" equal. Some carbohydrates move through the digestive system quickly, causing rapid increases in blood sugar. Other carbohydrates move through the digestive system slowly and, as a result, don't have much effect on blood sugar. The goal of the glycemic index diet is to base your diet around carbohydrates that can keep your blood sugar levels steady.
Glycemic Food Scale
The glycemic food scale ranks carbohydrates on a scale from 0 to 100 based on their effect on your blood sugar. Foods ranked from 0 to 55 are classified as low. These foods do not have a dramatic effect on blood sugar levels and should provide the basis of a glycemic index diet. Examples of low glycemic foods include apples, skim milk and beans. Foods ranked from 56 to 69 increase blood sugar levels moderately and should be limited. Examples of medium glycemic foods include bananas and raisins. Foods with a glycemic ranking from 70 to 100 are considered high and should be avoided entirely. Examples of high glycemic foods include potatoes and rice.
Considerations
The glycemic index classifies foods based on their individual effect on blood sugar levels. The amount of a certain food you eat, the time of day you eat and which foods you eat in combination can all affect your blood sugar. The glycemic index does not take these factors into account when rating foods. Because of this, MayoClinic.com notes that while it can provide a good foundation for a diabetic trying to control his blood sugar, it should not be relied upon solely.
