To determine a food’s index list (GI), laboratories typically conduct controlled experiments using human subjects.
Here is a general summary of the procedure:
Choice of Participants:
Laboratories recruit healthy people who are prepared to have fun playing the study. The participants might need to meet specific criteria, for example getting stable bloodstream sugar levels.
Test Food List:
The laboratory selects the meals to become tested. Typically, your meals are ingested in a standardized portion size that contains a quantity of carbohydrates.
Reference Food:
A reference food, frequently pure glucose or white-colored bread, can be used like a control. This meals are assigned a index list worth of 100, becoming a benchmark to compare.
Experimental Protocol:
Participants are expected to fast overnight prior to the experiment. Around the test day, they take in the test food or reference food under controlled conditions. Bloodstream samples will be collected at regular times, usually every fifteen to thirty minutes, more than a specific period of time, for example two hrs.
Bloodstream Glucose Measurement:
The collected bloodstream samples are examined to look for the glucose concentration. This really is typically done using enzymatic methods or automated glucose analyzers.
Glycemic Response Calculation:
The laboratory calculates the region underneath the glucose curve for the test food and also the reference food. This requires summing in the glucose concentrations each and every time point and modifying for that fasting glucose level. The region underneath the glucose curve supplies a way of measuring the entire fall and rise of bloodstream glucose within the testing period.
Index List Determination:
The index list will be calculated by evaluating the region underneath the glucose curve from the test food to that particular from the reference food. The formula used is: (Area under test food curve ÷ Area under reference food curve) × 100.
Record Analysis:
The laboratory may perform record analysis to guarantee the reliability and validity from the results. Including figuring out the variability among participants and assessing the value of any variations observed.
Most importantly the index list can differ between individuals and can also be affected by factors for example food processing, cooking methods, and the existence of other nutrients within the meal. Therefore, multiple trials and bigger sample sizes are frequently necessary to obtain additional accurate and reliable index list values for any specific food.