How Do You Calculate Glycemic Index?


Quick Answer

A Glycemic Index for a food is calculated from blood samples of human test subjects who have fasted overnight and then eaten that food, states Self NutritionData. To ensure the index is as consistent as possible, the portions used for these calculations are specified and fixed.

Continue Reading
Related Videos

Full Answer

Glycemic Index measures the effect on blood sugar for a certain food; the higher the number, the greater the effect on blood sugar, Self NutritionData informs. Glycemic Index values are calculated on a scale from 0 to 100, with pure glucose assigned a value of 100. Increased blood sugar creates a signal within the body to produce more insulin, which lowers the blood sugar level by turning the extra sugar present into fat. This reaction can be excessive, as a very high surge of insulin may decrease blood sugar to an undesirably low level. Insulin also plays a role in transporting glucose to muscle cells, so an elevated blood sugar level may be desirable after exercising.

Glycemic Index has a number of drawbacks that restrict its usefulness, mostly stemming from imperfect calculation methods and from interaction with other variables in real-world settings. Glycemic Index calculations are time-consuming, expensive and yield wide-ranging results that must be averaged to provide a useful estimate. In addition, glycemic response varies considerably among individuals, and different types of foods are eaten in isolation rarely, making it difficult to calculate the total Glycemic Index of a meal, notes Self NutritionData.

Learn more about Medical Ranges & Levels

Related Questions