What Is Glycemic Index (GI)?
Dt Sheetal chhabria
Vasanth nagar, Bengaluru Feb 9, 2017
Glycemic Index (GI) is a measurement or a rating carried out on carbohydrate-containing foods and the impact they have on our blood sugar. GI is sort of new way of analyzing foods. Earlier, most meal plans those were designed to improve blood sugar analyzed the total amount of carbohydrates, including sugars and starches, in the foods themselves. While GI goes beyond this approach. It looks at the impact of foods on our actual blood sugar.
In other words, instead of measuring the total amount of carbs in foods in their unconsumed state, GI analyses the actual impact of these foods on our blood sugar, after being consumed.
Why Is GI Important?
Over last decade, low-GI diets have been linked with decreased risk of cardiovascular disease, diabetes-II, metabolic syndrome, stroke, depression, chronic kidney disease, formation of gall stones, neural tube defects and many other known health conditions. Using these potential health benefits can be as simple as sticking with natural foods in raw state that are either low or very low in their GI value.
How Is GI Measured?
Typically, a food is consumed in any serving size to provide 50 grams of available carbohydrates. Available carbohydrates (or avCHOs) are carbohydrates that get easily digested, absorbed, and metabolized by our digestive system. These carbohydrates have a huge impact on our blood sugar level than carbohydrates in general as carbohydrates in general include compounds that are not readily digested, absorbed, and metabolized. For example, insoluble fibers are carbohydrates that do not have an immediate effect on our blood sugar level because they cannot be readily digested. A normal way of estimating available carbohydrates in a serving of food, researchers take into account the total amount of carbohydrates and subtract out the total amount of fiber. Remaining will be the available carbohydrates.
In order to measure GI, upon consumption of 50 grams of available carbohydrates, blood sugar levels are measured over a period of 2 hours. The results are then represented in a graphical manner and summarized in what is called glucose AUC, or "area under the curve". Glucose AUC shows the immediate effect of the food on our blood sugar level.
Accounting for GI also requires a second step. In this step, 50 grams of available carbohydrates(aCOHs) are consumed, but this time the food involved is one of two reference foods: either pure sugar (pure glucose) orwhite bread.Once again the blood sugar levels are measured over a similar period of 2 hours, and the glucose AUC is calculated. Now it is possible to compare the two results at this point. The impact of the first food on our blood sugar is compared to the impact of eitherglucoseor white bread itself. On comparison of these two results, the impact of the glucose or white bread is arbitrarily given a value of 100 to make the required comparison easier. For example, if we have to establish a GI for green peas and to compare the impact of green peas on blood sugar to the impact of white bread. If a person consumes a starchy vegetable like green peas, and the glucose AUC is 48% as large the glucose AUC when white bread is consumed. Therefore, the GI for green peas would be established at 48% of 100, or will be 48.
GI Rating System
Most organizations use a "high," medium" and "low" system for GI rating. Using this system, foods are classified in the following way:
|0-55||56-69||70 or greater|
GI Ratings for the World's Healthiest Foods
Very Low GI
|World's Healthiest Foods|
|bell peppers||green peas||sweet potatoes|
|Brussels sprouts||winter squash|
|Romaine and other lettuce|
|plums & prunes|
|Nuts & Seeds||flaxseeds||almonds|
|Beans & Legumes||soybeans||black beans|
|cow's milk, grass-fed|
|World's Healthiest Spices and Herbs||black pepper|
|cilantro & coriander seeds|