Glycemic Index and Glycemic Load: Know the Difference



By Amber Alexander

Amber Alexander

Much of dieting focus recently has been placed on the glycemic index. While understanding and managing the glycemic index is important, it's equally important to go one step further and understand glycemic load. The glycemic load is a relatively new way to measure the impact of food to blood glucose levels. Simply put, glycemic index represents glucose conversion speed, while glycemic load represents the amount of glucose created.

So What's the Glycemic Index?

The glycemic index is the relative degree to which blood sugar increases after the consumption of food, that is, relative to the effect of pure sugar. High glycemic index foods can raise blood glucose levels very quickly, as well as insulin levels. In contrast, low glycemic index foods don't significantly raise blood glucose levels and insulin levels after eating. Pure glucose is given a value of 100 while other foods are given an index number representing its relative effect on blood glucose levels.

For example, sweet corn has an index number of 55 meaning it raises blood glucose levels 55 percent as much as pure glucose. Generally, foods below 55 are considered low glycemic index foods, 55-70 represents mid-glycemic index foods and over 70 are considered high glycemic foods. Previous belief was that simple sugars dramatically increased blood glucose levels while starches such as potatoes and bread were digested slowly. The results from numerous studies, however, show this is not the case. Potatoes, for example, reported an average index of 84, making it one of the higher glycemic foods available.