What is the Glycemic Index?
The glycemic index (GI) helps us understand how to rate simple and complex carbohydrates relative to how quickly they breakdown and are absorbed into our body as glucose (sugar). For diabetics this process is critical as we may need to compensate with insulin, medications, exercise or other food choices (i.e., protein based foods). For athletes it is important, as carbohydrates affect your blood sugar metabolism and can thus affect your performance ability. For "normal" people, too many carbohydrates might show up as a sugar high, where your head or heart is pounding, or you experience over-excitability. The crash of a sugar low might manifest itself as a migraine, fatigue, sleepiness or nausea. The glycemic index is basically calculated by measuring the blood glucose response to 50 grams of a specific food over a two hour period to obtain a relative index value.
What is Glycemic Load?
Glycemic load (GL) is different in that it rates food according to its carbohydrate and fiber composition. It is calculated by multiplying the GI value by the "available carbs" per serving (carb grams minus the fiber grams = available carbs) and then dividing it by 100 to obtain the index value.
Foods with a GL of 10 or less are good choices for stabilizing blood sugar levels. These foods normally include fresh vegetables and fruits with fiber, rather than processed items. Foods rated in the 11-19 load category (see chart below), have a moderate affect on blood sugar, and those 20 and over should be eaten sparingly as they spike blood sugar levels very quickly. (There are a couple food list links posted below.)