What is Glycemic Index?

What is glycemic index of food that makes it so helpful for people with diabetes?  The index is a sophisticated scale which ranks carbohydrate-rich foods by how much they raise your blood glucose compared to a ‘standard’ food such as glucose. Foods that are harder to digest have a lower glycemic index. Easy as pie? Not quite. It is not just a matter of choosing low glycemic index foods and being done with it. Fat content in a food can make it harder to digest, and therefore have a lower glycemic index, but that doesn’t mean we can have our way with all the high fat foods.

Glycemic Index Chart: A low glycemic index food is assigned a number of 55 or less. A medium glycemic food has a value between 56 -69; high glycemic foods rank above 70. Glycemic index charts are really needed to sort out which foods, combined with which preparation methods, have a low glycemic index. Since most food labels do not list a glycemic index value, these charts are really necessary. Some charts are very creative using a green-amber-red traffic light analogy for food choices. Others use a food pyramid to help visualize how much of a certain food can be included in a healthy diet. Still others use a temperature gauge to indicate foods along the glycemic index.

Low Glycemic Index Foods: Keeping in mind that the glycemic index measures how long your body takes to digest a food and convert it to glucose, it is not surprising that many high fiber foods have a low glycemic index. Lentils, barley, whole grains and brown rice are low glycemic index foods. Processed grains or rice with the outer roughage stripped off have a higher glycemic index. Within a food group such as fruit, for example, pears have a lower glycemic index than watermelon. For the same food, a boiled new potato has a lower glycemic index than a baked potato.

Glycemic Index Table: Using a glycemic index table is a helpful method to start sorting these factors out. Some tables will show one food, such as a potato, across three columns from low to high glycemic index based on the method of preparation. We all know that just using a number as a basis for building a healthy diet is too simplistic. For example, so-called empty calories don’t provide us with much in the way of nutrition. Similarly, simply choosing low glycemic index foods does not consider factors such as fat content of a food, or the type of fat.