Many popular diet books recommend avoiding foods with a high Glycemic Index. When you eat a food, your blood sugar level rises. The food that raises blood sugar the highest is pure table sugar. The Glycemic Index (GI) is a ratio of how high a food raises blood sugar in comparison to table sugar. Foods whose carbohydrates break down slowly release glucose into the bloodstream slowly, so blood sugar levels do not rise high and therefore these foods have low GI scores. Those that break down quickly cause a high rise in blood sugar and have a high GI. Most beans, whole grains and non-starchy vegetables have low GI; while sugars, refined grains, fruits and root vegetables have a high GI. A carrot has almost the same GI as sugar, but common sense tells you that a carrot is more healthful than table sugar. Foods that are mostly water or air will not cause a steep rise in your blood sugar even if their GI is high. That's why a new measure, called Glycemic Load (GL), is more useful. This tells you how much sugar is in a portion of food as well as how high it raises blood sugar levels. GL is calculated by multiplying the grams of carbohydrate in a serving of food by that food's glycemic index. Carrots dropped from high GI of 131 to a GL of 10. Potatoes fall from a GI of 121 to a GL of 45. Air-popped popcorn, with a GI of 79, has a GL of 4. GI and GL indexes are tools for research that will drive you crazy if you try to apply them to your daily selection of foods. Instead, use your own common sense and eat plenty of fruits, vegetables, whole grains, beans and other seeds. If you are diabetic, you can eat root vegetables and fruits with other foods to slow the rise in blood sugar they may cause. For more on GL and sensible nutrition, read "Eat, Drink, and Be Healthy: The Harvard Medical School Guide to Healthy Eating" (Simon & Schuster, June 2001), by Harvard School of Public Health professor and researcher Walter Willett, M.D -- highly recommended. |
