By now you've probably read or heard something about the glycemic index (GI) — for example, how using the index to make food choices may help prevent and manage certain diseases, such as type 2 diabetes and heart disease. Many health organizations, including the Canadian Diabetes Association and the World Health Organization, support the use of the GI for individuals with diabetes.
But the GI is becoming an increasingly hot nutritional concept for people who don't already suffer from a chronic disease. Many prominent nutrition researchers and dietitians see it as a promising approach to healthy eating and the prevention and treatment of some chronic diseases.
The GI is a valid and potentially useful concept, but it is also complex and can be difficult to follow. Because the science around the GI is still quite young, there are some unanswered questions. As the science evolves, and researchers learn more about the GI and its role in the prevention and treatment of chronic diseases, these questions will be answered. Until then, read “The GI Diet Made East&" in the October 2004 issue of Canadian Living for a no-nonsense, nuts-and-bolts approach to incorporating GI principles into your family's diet.
Also, Emily Richards has chosen some delicious low-GI recipes from The Canadian Living Test Kitchen to help make the healthy eating transition a little easier:
1. Mexican Style Bean Salad
2. Bean Burgers with Coriander Cream
3. Cajun Rainbow Trout (Salmon)
4. Three Cheese Polenta with Quick Chunky Tomato Sauce
5. Chicken in Tomato Zucchini Sauce
6. Stir-Fried Beef and Greens
What Is the glycemic load?
The glycemic load is a relatively new way to assess the impact of carbohydrate consumption on your blood sugar. It takes the GI into account but gives a fuller picture than the GI alone. A GI value tells you only how quickly a particular carbohydrate-containing food turns into sugar; it does not tell you how much of that carbohydrate is in a serving of a particular food. You need to know both things to understand a food's effect on blood sugar.
When you eat a carbohydrate-containing food, your blood sugar rises as the food is digested, then falls as the glucose is used by cells for energy or stored as fat for later use. The extent to which it rises and remains high depends on the amount of a carbohydrate in the food and the glycemic index of that food. The glycemic load combines these two factors to provide a measure of blood-sugar response to a particular food as well as the insulin demand produced by a normal serving of that food. For example, if a food contains very little carbohydrate, it will not have much impact on blood sugar and insulin levels, regardless of its glycemic index. On the other hand, if a given food has a high glycemic index and a high carbohydrate content, blood glucose and insulin will quickly increase.
How the glycemic load is calculated:
Glycemic Load = (GI of the food x amount of carbohydrate in the serving*) /100
For example, a medium orange has a GI value of 44 and contains 10 grams of carbohydrate. Its glycemic load is (44 x 10) /100 = 4.4. A small potato has a GI value of 90 and 15 grams of carbohydrate. It has a glycemic load of (90 x 15) /100 = 14. One small potato will raise your blood glucose level higher than one orange.
*The amount of carbohydrate in a serving of food can be found on the product label in the Nutrition Facts Panel of most packaged foods and in the nutrition information at the end of Canadian Living recipes.
Glycemic load range:
Low glycemic load = 10 or less
Medium glycemic load = 11 to 19
High glycemic load = 20 or more
The glycemic index can be used to compare foods, and the glycemic load can be used when you're deciding on the portion size of the food you plan to eat.
What are the GI values of my favourite foods?
Foods that contain carbohydrates are classified as having a low, medium or high GI. A low-GI food has a GI of 55 or less, a medium-GI food has a GI of 56 to 69, and a high-GI food has a GI of 70 or more.
Low-GI foods (55 or less)
Grain products: multigrain bread, 100% stone-ground whole wheat bread, pumpernickel bread, sourdough bread; bran cereal with psyllium, oat bran cereal, rolled oats, wheat bran cereal (not flakes); pasta; brown rice, parboiled or converted rice (partially cooked rice, such as Uncle Ben's), wild rice; barley; bulgur
Vegetables: broccoli; cabbage; cauliflower; celery; fennel bulb; green and yellow beans; leafy green vegetables, such as arugula, bok choy, collard greens, kale, romaine lettuce and spinach; mushrooms; peppers (sweet and hot); salsa; sweet potatoes; tomatoes; vegetable cocktail; yams; zucchini
Fruits: apples, avocados, bananas, berries, cherries, grapefruit, nectarines, pears, unsweetened fruit juice
Milk products: low-fat ice cream or frozen yogurt, milk, yogurt
Meat and alternatives: eggs; legumes, such as black beans, chickpeas, lentils and kidney beans; meats, including lean beef, chicken and pork; fish; tofu
Other: oatmeal cookies, sponge cake
Medium-GI foods (56 to 69)
Grain products: basmati rice, couscous, instant oatmeal, pita bread, rye bread
Vegetables: beets, boiled white potatoes, new potatoes, sweet corn
Fruits: cantaloupes, figs, papaya, pineapples, raisins
Milk products: full-fat ice cream
Other: angel food cake, croissants, shortbread cookies, tortilla chips
High-GI food (70 or more)
Grain products: bran flakes, cornflakes, soda crackers, white bread, white rice
Vegetables: carrots; french fries; mashed, baked or microwaved white potatoes; parsnips, pumpkin, rutabaga
Meat and alternatives: broad beans
Other: cookies (except oatmeal), cupcakes, doughnuts, popcorn, potato chips, pretzels, regular soft drinks, scones