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The Glycemic Index: What You Need to Know

Nina Ghamrawi, MS, RD, CDE
March 16, 2023
March 16, 2023

The glycemic index is a tool that helps you understand how quickly different foods can raise your blood sugar levels. The glycemic index is a number that ranges from 0 to 100, with higher numbers indicating a faster rise in blood sugar levels.

How to Use the Glycemic Index

To use the glycemic index, look up the index number for different foods. Foods with high glycemic index numbers, such as white bread and sugary drinks, raise blood sugar levels quickly. Foods with low glycemic index numbers, such as lentils and nuts, raise blood sugar levels more slowly.

When choosing foods, it is important to consider both the glycemic index number and the serving size. Using the glycemic load calculation can help with this.

Glycemic Load:

Glycemic load (GL) is a measure of the impact of a food on blood sugar levels that takes into account both the glycemic index (GI) and the serving size of the food. The glycemic load is calculated by multiplying the glycemic index of a food by the amount of carbohydrates in a serving size, and then dividing by 100.

For example, if a food has a glycemic index of 70 and a serving size contains 15 grams of carbohydrates, the glycemic load of that food would be 10.5 (70 x 15 / 100).

Glycemic load can give a more accurate picture of how a food will impact blood sugar levels compared to the glycemic index alone, as it considers both the speed at which a food raises blood sugar levels and the quantity of carbohydrates in a serving.

Benefits of Using the Glycemic Index

Using the glycemic index can be helpful for people with diabetes or other conditions that affect blood sugar levels. By choosing foods with a low glycemic index, people with these conditions can help manage their blood sugar levels and reduce the risk of complications. But its definitely not fool-proof, and actually not found to be very accurate.

Shortcomings of Using the Glycemic Index & Glycemic Load

While the glycemic index and load are useful tools, they are not a perfect system. Some foods, such as those with a high fat content, can slow down the digestion and absorption of carbohydrates, which can lower the glycemic index of the food. Additionally, the way a food is prepared can also affect its glycemic index, as well as the temperature of it, and the make or brand. Other things that affect your body’s response to food is your gut health and bacteria, genetic factors, and glucose tolerance.

In conclusion, the glycemic index is a tool that can help you understand how quickly different foods can raise your blood sugar levels But it is not a perfect tool, and has so many shortcomings that it may be soon retired. For some better ways to control your carbohydrate intake, use the exchange list system to count carbohydrates, and make sure they are high quality carbs.