The glycemic index (GI) is a ranking of carbohydrate foods individuals with diabetes use to manage their disease. This ranking is based on the rate carbohydrates affect blood glucose levels relative to glucose or white bread.
Generally, the glycemic index is calculated by measuring blood glucose levels following the ingestion of a carbohydrate. This blood glucose value is compared to the blood glucose value acquired following an equal carbohydrate dose of glucose or white bread.
Glucose is absorbed into the bloodstream faster than any other carbohydrate, and is thus given the value of 100. Other carbohydrates are given a number relative to glucose. Foods with low GI indices are released into the bloodstream at a slower rate than high GI foods.
A number of factors influence the digestion and absorption rate of food, including ripeness, particle size, the nature of the starch, the degree of processing and preparation, the commercial brand, and the characteristics of the diabetic patient, and these factors naturally affect each food’s glycemic index position or rank.
In addition, differences exist in the glycemic indeces of foods due to the choice of reference food, the timing of blood sampling, or the computational method used to calculate the glycemic index.
The glycemic index measures the quality rather than the quantity of carbohydrates found in food. Quality refers to how quickly blood sugar levels are raised following eating.
The GI is a standard— 10รพ healthy people consume a digestible carb (usually white bread), and their blood glucose rise is followed for the next two hours—that is assigned an index value of 100.
Other foods are compared to the standard in order to arrive at their ratings. The higher the GI number, the faster blood sugar increases when that particular food is consumed.
A high GI is considered to be 70 and greater, a medium GI is 56–69, and a low GI value id 55 or less.
In general, low-carb diets recommend a glycemic load (the total GI number in foods consumed per day) of 80 or less. Ahigh glycemic load is considered to be 120 or more.
