This comes and goes with regard to popularity, and right now it seems to be back. The Glycemic Index (GI) shows what happens to our blood sugar when we digest different types of carbohydrates. Carbohydrates that break down quickly cause a quicker rise in blood sugar than those that break down more slowly. Foods are ranked according to the effect of 50 grams of carbohydrate from a particular food on blood sugar in comparison to the effect of 50 grams from glucose. The index is a scale of 1-100, with glucose being assigned 100. Originally, the GI was developed as a research tool for use with people with diabetes.
In general, foods that have a lower GI score will have a lower impact on glucose levels. Foods that have a GI of less than 55 are considered “low”. Foods with a GI of 55-70 are considered “moderate”, and foods that are above 70 are considered “high”.
There are many problems with trying to apply the data from the GI to every day eating.
First of all, most eating does not involve eating carbohydrate by itself. Second, the GI is based on 50 GRAMS of carbohydrate of a single food, which may be significantly more than a person would eat of a particular food. Third, there are many variables that can affect the GI of a food: ripeness, the presence of acid in a food, individual differences in people’s digestion, cooking time, just to name a few.
Another key issue with the GI index is that you can’t make an educated guess about which foods are low or high. You have to look it up. Potatoes are not all the same. Orange juice is different from oranges.
With all that being said, there is certainly nothing wrong with looking for ways to increase your intake of foods that are good for you. If the GI is something you feel is valuable and helpful, have at it! There are plenty of great books and cookbooks out there on the subject. Just remember one thing: Eating should be easy. Don’t get so caught up in a “system” that you forget to enjoy the simple pleasure of eating foods you enjoy.