The Glycemic Index is a numerical Index that ranks carbohydrates based on their rate of glycemic response, or in other words, their conversion to glucose within the human body. The Glycemic Index uses a scale of 0 to 100, with higher values given to foods that cause the most rapid rise in blood sugar. Pure glucose serves as a reference point and is given a Glycemic Index (GI) of 100.
Your body performs best when your blood sugar is kept relatively constant. If your blood sugar drops too low, you become lethargic and/or experience increased hunger. And if it goes too high, your brain signals your pancreas to secrete more insulin. Insulin brings your blood sugar back down, but primarily by converting the excess sugar to stored fat.
When you eat foods that cause a large and rapid glycemic response, you may feel an initial elevation in energy and mood as your blood sugar rises, but this is followed by a cycle of increased fat storage, lethargy, and more hunger.
The theory behind the Glycemic Index is simply to minimize insulin-related problems by identifying and avoiding foods that have the greatest effect on your blood sugar. What are some of those foods?
Most fruits have a low GI rating because they contain lots of fiber. Fruits such as apples, bananas, grapes, nectarines, plums, and peaches are a few to add to your eating lifestyle. You should avoid dried fruits such as dates, raisins, and sweetened cranberries because they do not contain fiber.
Grains and Starchy Vegetables
One thing is for sure: if you are going to eat grain foods, pick the ones that are most nutritious. Choose whole grains which are rich in vitamins, minerals, phytochemicals (phyto is Greek for plant) and fiber.
Reading ingredient labels on packages is essential so that you make the best choices. Every time you choose to eat a starchy food, make it count. Leave the processed white flour-based products, especially the ones with added sugar, on the shelves. Select foods that have the entire grain, which includes the bran, germ, and endosperm.
I am not suggesting that you avoid all high-GI foods. For non-diabetics, there are times when a rapid increase in blood sugar (and the corresponding increase in insulin) may be desirable. For example, after you finish a strenuous workout the insulin helps move glucose into muscle cells, where it aids tissue repair.