Glycemic Index and Glycemic Load: How Your Body Processes Carbs
We know that different nutrients are processed by the body in different ways, but do you know what foods to choose to ensure optimal health, digestion, and nutrient use? Even within the category of carbohydrates, different foods are processed at different rates and by different mechanisms. Rather than just eating what you want and hoping for the best, a glycemic index has been created to help guide your choices based on how your body will respond to them.
What Is the Glycemic Index?
The glycemic index (GI) is a system that was created by physicians in the 1980s to help people distinguish between carbohydrates that are quickly digested by the body (and quickly enter the bloodstream as glucose) and those that are processed more slowly (a good thing). Foods are assigned a number (calculated in food laboratories) that correlates with how quickly the body processes that form of carbohydrate/sugar.
Higher numbers are assigned to foods that are processed quickly and elevate your blood sugar more rapidly, whereas low numbers are given to foods that don’t impact your blood sugar so strongly. Pure glucose is considered 100. A general rule of thumb is:
- ≤55 = low GI (good)
- 56-69 = moderate GI
- ≥70 = high GI (negatively impacts blood sugar)
What Is a Glycemic Load?
For the people out there who enjoy crunching the numbers, the glycemic index can be taken a step further and applied more directly by calculating the glycemic load. Glycemic load (GL) is obtained by multiplying the GI (potential to raise blood glucose) by the amount of carbs in that food in a serving (in grams) and then dividing that total by 100. This number is more concrete, since it takes the actual amount you will consume into account.
For example, a candy bar that has 34 grabs of carbs and a GI of 68 would have a glycemic load of 23. So you could compare that with an apple that has 16 grams of carbs and a GI of 34, resulting in a glycemic load of 5.
- GL ≥ 20 is considered high
- GL 11-19 is moderate
- GL ≤ 10 is low
The glycemic index is a great way to get an idea of the impact sugars and carbs can have on the body, and calculating the glycemic load gives you a more specific idea of how a serving or meal will impact your blood sugar.
Glycemic Index Examples
Here are some examples of foods with high, moderate, and low glycemic indexes:
- Mashed potato: 87
- Cornflakes: 81
- White rice: 73
- Popcorn: 65
- Table sugar (sucrose): 65
- Honey: 61
- Mango: 51
- Orange: 43
- Carrots (boiled): 39
- Skim milk: 37
- Apple (raw): 34
Of course, the glycemic index isn’t the end-all-be-all of food navigation. First, not all foods are perfectly consistent. For example, bananas’ sugar content changes as they ripen, causing their glycemic index to increase. For certain foods like pasta or starchy vegetables, method of preparation and cook time impact their glycemic load. Second, other factors impact your digestion and blood sugar, including the other foods you consume in conjunction with these carbs, the state of your personal digestive system, health problems like diabetes, etc.
Using the glycemic index as a guide to choose foods that will help stabilize your blood sugar is an easy way to improve your health, inside and out.