The Glycemic Index Diet for Dummies - Meri Raffetto [8]
Getting to Know the Glycemic Index
The glycemic index is a scientific way of looking at how the carbohydrates in foods affect blood glucose, or blood sugar, levels. Scientists know that all carbohydrates raise blood sugar, but the glycemic index takes this understanding one step further by figuring out how much a specific food raises blood sugar.
When you use the glycemic index to plan your meals and snacks, you're following a glycemic index diet. It's not a "diet" in the sense that there are specific meal plans you need to follow, lists of foods to eat and foods to avoid, and other types of rules that are all too familiar to people who've tried various weight-loss diet plans. Instead, the glycemic index gives you a method for selecting foods that meet your specific needs and desires.
You know those oerlay maps, where you start with a very basic map, add an overlay with more detail, then add another overlay with yet more detail, and so on until you have a complete picture of a specific area? Think of using the glycemic index in a similar way.
The first "overlay" is basic meal planning. Your body tells you it's hungry and wants food.
Next comes the layer of basic nutrition, which is all about balance. Your meal needs to include protein (chicken, fish, lean red meat, soy products, eggs, nuts/seeds), vegetables, and starch (potato, pasta, rice, bread) to keep your body happy. If you throw in a glass of milk and some fruit on the side, your body will be even happier.
Finally, you add in the glycemic index for a complete picture. Because the glycemic index applies solely to foods that contain carbohydrates, it applies only to the vegetable, starch, milk, and fruit portions of your meal. Theoretically you already have an understanding of these foods' nutritional values. The glycemic index completes the picture by telling you how these foods will impact your blood sugar, which affects everything from your energy level to your food cravings.
Now that you have a basic understanding of the glycemic index, check out the following sections for the scoop on how it's measured and how an added bit of information makes it even more valuable.
Measuring the glycemic index
The glycemic index ranks foods on a scale of 0 to 100 based on how quickly they raise blood sugar levels. Foods that raise blood sugar quickly have a higher number, whereas foods that take longer to affect blood sugar levels have a lower number.
To measure the glycemic index of a food, a specific weight of the digestible carbohydrates in the food (usually 50 grams, which is about 4 tablespoons of sugar) is fed to at least ten different people who volunteer for the study. Their blood sugar levels are measured every 15 to 30 minutes over a two-hour period to develop a blood sugar response curve. The blood sugar response of each food is compared to that of a test food, typically table sugar (glucose), which is assigned the number 100. The responses for each test subject are averaged, resulting in the glycemic index number for that food. Every individual person may have a slightly different glycemic (blood sugar) response to foods, which is why the tests use a number of volunteers and average their results together.
The information on glycemic index (GI) lists is divided into three basic categories so you don't have to get caught up in numbers and can instead focus on the primary goal of the glycemic index — choosing foods that keep your blood sugar levels more even, resulting in longer-lasting satiety (the feeling of fullness) and improved health. Here are the