What is Glycemic Index?

     Most people have heard of the term "glycemic index," but many don't know what it means. The glycemic index (GI) is a measure of how quickly a certain food causes our blood sugar levels to rise. The glycemic index uses a scale from zero to one hundred to rank foods. Foods on the high end of the GI scale are digested and absorbed quickly, which raises blood sugar levels quickly. Foods with a high GI are typically low in dietary fiber and high in carbohydrates. 

    The glycemic index is useful, although there are two major limitations to consider when using it. The GI of a food is measured when it is consumed on an empty stomach without other foods. When different types of foods are eaten together, it can be harder to rely on the GI because protein, fat, and fiber can affect how quickly blood sugar levels rise. The second limitation is that GI does not reflect the portion sizes that are commonly consumed. The GI is determined by giving people a serving of food containing 50 grams of a carbohydrate food, without its fiber, and monitoring their blood sugar levels for two hours. However, the amount of food needed to provide 50 grams of carbohydrates may be much larger than a typical serving. Glycemic load is another way to understand how foods affect blood sugar levels. It is calculated by multiplying the grams of carbohydrates in a serving by the food's GI, and then dividing that number by 100. Overall, the glycemic index is not a perfect system, but it can be a useful tool for identifying foods that may cause a slower rise in blood sugar levels. For the slowest rise in blood sugar, it is important to choose nutritious foods that incorporate protein, fiber, and healthy fats into one meal. 

Source: https://www.eatright.org/health/wellness/diet-trends/what-is-glycemic-index