When asked "what is a glycemic diet?", I typically find that the person asking is under the assumption that a glycemic diet is complicated. Wouldn't you agree that the word "glycemic" sounds pretty scientific? And science is complicated, right?
In fact it is quite simple to follow a glycemic diet without knowing too much about the science behind it. In the simplest of terms it is a "diet" where you are solely eating foods with a low to moderate Glycemic Index.
The reason I emphasize "diet" is because it is not really a diet in the negative "fad -diet" sense of the word. In fact the glycemic index has been around and in use for more than 25 years, and has been used to help diabetics and others with glucose related conditions (such as hypoglycemia) formulate an appropriate nutrition plan.
Glycemic index (also glycaemic index, GI) is a ranking system for carbohydrates based on their effect on blood glucose levels in the first two hours after ingestion.
Carbohydrates that break down rapidly during digestion have the highest glycemic indices. Carbohydrates that break down slowly, releasing glucose gradually into the blood stream, have a low glycemic index. A lower glycemic index suggests slower rates of digestion and absorption of the sugars and starches in the foods.
The glycemic index of a food is defined by the area under the 2 hour blood glucose response curve (AUC) following the ingestion of a fixed portion of carbohydrate (usually 50 g). The AUC of the test food is divided by the AUC of the reference food. The current validated methods use glucose as the reference food, giving it a glycemic index value of 100 by definition.
The average GI value is calculated from data collected in 10 human subjects. Both the standard and test food must contain an equal amount of available carbohydrate. The result gives a relative ranking for each tested food.
Foods that have been scientifically measured for GI value usually fall within a low, moderate, or high range.
Low: 55 or less
Moderate: 56 - 69
High: 70 or more
Note: It is possible for some foods to have a GI value of greater than 100. That is higher than the response for the reference food glucose.