What is the Glycemic Index

Imagine a Celsius thermometer. Zero (0) degrees is the measure for the Freezing point of water and 100 degrees is the measure for the Boiling point of water. Having these 2 measurements allows us to measure all the other temperatures relative to these 2 standards.  For example, room temperature is 20C (68F)

The Glycemic Index was created to operate kind of like a thermometer.  When people drink plain water, it’s doesn’t affect their blood sugar levels in any way, so water is ranked as “zero” on the Glycemic Index.  Pure glucose, on the other hand, sends a person’s blood sugar skyrocketing, so glucose is ranked as a “100″ on the Glycemic Index.  With these 2 standards, we can now rank other foods relative to these.

Foods with a high GI are those which are rapidly digested and absorbed and create large fluctuations in blood sugar levels. Low-GI foods, because of they are slowly digested and absorbed, produce gradual rises in blood sugar and insulin levels.  Low GI diets have been shown to improve both glucose and lipid levels in people with diabetes (type 1 and type 2). They have benefits for weight control because they help control appetite and delay hunger. Low GI diets also reduce insulin levels and insulin resistance.

GI ratings are determined by feeding measured portions of the food containing 10 – 50 grams of carbohydrate to 10 healthy people after an overnight fast. Finger-prick blood samples are then taken at 15-30 minute intervals over the next two hours. These blood samples are used to construct a blood sugar response curve for the two hour period.

The rankings for foods are as follows:

0 – 55 = Best choices

56 – 69 = Moderate choices

70 + = Worst choices

Click HERE for a document that provides a very thorough listing of the Glycemic Index of many foods.  You may be shocked by some of the numbers.  For example:

most vegetables – 0
apple – 38
cherries – 22
grapefruit – 25
grapes – 48
raisins – 64
white sugar – 62
bagel – 72
French baguette – 95
Rice Chex cereal – 89
Corn Flakes – 84
dried dates – 103
Gatorade drink – 78
French fries – 79

Glycemic index can be lowered by adding fat, fiber or protein.  Fructose, while a “simple” sugar, must be converted into glucose, and that takes time. Starch, while a “complex” carbohydrate, is basically just glucose linked in a chain. The bonds are rapidly broken, and the former starch is quickly sent into the blood in the form of glucose.  This is why fruit has a lower GI rating than bread.

Spiking your blood sugar sends your insulin levels soaring, stresses the pancreas and leads to a “crash” which then causes more sugar cravings.  Eat low glycemic foods for better health.

From Linda Miner's "My Healthy Balance"