The glycemic index is used to rank food on a scale from 1 to 100. The scale is used to tells us how the carbohydrate in the food affects our blood sugar.

Food with high glycemic-index digests quickly in the digestive system. A large amount of glucose is being released to the blood stream quickly, and that naturally sharply raises the blood sugar level. Due to the sudden high level of blood sugar, a large amount of insulin is released. Insulin is needed to regulate the level of blood sugar. The more sugar (glucose) that is present in the blood, the more insulin that will be released from the pancreas. Without insulin, sugar can not enter the various cells in our body. The insulin signals cells to absorb sugar from the bloodstream to be used for energy. If there’s more sugar in the blood than the body needs, insulin will “direct” it to be stored in the liver or muscles as glycogen, to be released at a later time, when the blood sugar level is low.

It is important to know that insulin inhibits the breakdown of stored body fat. It also forces fat cells to take up and store fat from the blood. High levels of insulin lead to increased fat storage, whereas low levels of insulin lead to fat depletion.

Food with low glycemic-index digests slower, the blood sugar level is raised in moderation and over time. The added benefits of having consistent low blood sugar levels are that less muscle tissue loss is minimal, the body uses energy that is stored in the body as fat, and we feel full longer.

High blood sugar level is bad for you on so many levels. The pancreas has to make high levels of insulin, and over time the pancreas can get damaged and not produce the necessary levels of insulin, which may lead to diabetes type II. In addition, high blood sugar levels damage blood vessels which can cause heart attacks, strokes, blindness, kidney failure, poor circulation to legs, and more.

To make a long story short, we DO NOT want to have high blood sugar.

One way is to decrease the amount of high glycemic food we eat. Foods with levels up to 55 are considered to have low glycemic index (GI), 56-69 are considered medium, and 70 and higher are considered to be high. Therefore, eating rice (27) is better than eating baked potato (121).

As a rule of thumb, foods with simple sugar, starch food, processed food and cooked food have higher GI.  Fiber and protein help lower the GI. Here is a link to a list of 100 common foods published by the Harvard Health Publication.

It’s important to remember that food with high GI can be a good choice under some circumstances (e.g., when you need to recover after exercise).