Glycemic Index and Blood Glucose Level

Glycemic Index (GI) is a relative ranking of carbohydrates (Sugar) in foods according to how it affects blood glucose levels. High GI foods are high in simple sugars that can rise blood sugar levels immediately after consumption. This further leads to a rapid rise in insulin levels with adverse effects on health.

Low Glycemic Index ranking foods are more slowly digested, absorbed, and metabolized. They cause a lower and slower rise in blood glucose and, therefore insulin levels. Our body will digest these foods slowly. You will feel full for a long time and you would be eating fewer calories without feeling hungry. This means foods with lower GI are beneficial for weight loss. They also decrease the risk of cardiovascular disease, type 2 diabetes, stroke, depression, formation of gall stones, chronic kidney disease, metabolic syndrome, neural tube defects, formation of uterine fibroid, and cancer of the breast, colon, prostate, and pancreas.

How is Glycemic Index given to a food?

The Glycemic Index is a value obtained by monitoring a person’s blood sugar serially at fixed intervals after eating the food. Initially, 10 or more healthy people are given a quantity of food to be tested containing 50 grams of carbohydrates, and their blood glucose levels are checked over the next two hours. For each person, the incremental area under their two-hour blood glucose response (glucose iAUC) for this food is then measured. On another occasion, the same 10 people consume an equal-carbohydrate portion of plain glucose sugar and their two-hour blood glucose response is also measured. A GI value for the test food is then calculated for each person by dividing their glucose iAUC for the test food by their glucose iAUC for the reference food. The final GI value for the test food is the average GI value for the 10 people.

The Glycemic Index  range is as follows:

Very Low or Low GI =55 or less;

Medium GI = 56-69;

High GI = 70 or more.

Making a healthy choice:

Exchange high Glycemic Index foods for low GI foods. Eat at least one serving of low-GI carbohydrate food at each meal. Keep a watch on the serving size as eating too much food, is not all that good.
You don’t need to completely cut out high GI options – the trick is to combine them with low GI options to get to a moderate Glycemic Index. Certain acids have been proven to lower the GI of certain foods. A few examples can be adding vinegar to salads, yogurt with cereal, and lemon or lime juice to vegetables. How you cook them also has an impact on the Glycemic Index given to a particular food.

Written by MedPlus