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How to Use the Glycemic Index

Some foods can make your blood sugar shoot up very fast. That's because carbohydrates like refined sugars and bread are easier for your body to change into glucose, the sugar your body uses for energy, than more slowly digested carbs like those in vegetables and whole grains. Eat a lot of those easy carbohydrates and you'll have a hard time controlling your blood sugar, even with insulin and diabetes medications.

The glycemic index gives you a way to tell slower-acting "good carbs" from the faster "bad carbs." You can use it to fine-tune your carb-counting and help keep your blood sugar more steady.

What Is the Glycemic Index?

Glycemic index is a number. It gives you an idea about how fast your body converts the carbs in a food into glucose. Two foods with the same amount of carbohydrates can have different glycemic index numbers.

The smaller the number, the less impact the food has on your blood sugar.

  • 55 or less = Low (good)
  • 56- 69 = Medium
  • 70 or higher = High (bad)

Look for the glycemic index on the labels of packaged foods. You can also find glycemic index lists for common foods on the Internet. Harvard University has one with more than 100. Or ask your dietitian or nutrition counselor.

Foods that are close to how they're found in nature tend to have a lower glycemic index than refined and processed foods.

Glycemic Index Can Change

That number is a starting point on paper. It could be different on your plate, depending on several things.

Preparation. Fat, fiber, and acid (such as lemon juice or vinegar) lower the glycemic index. The longer you cook starches like pasta, the higher their glycemic index will be.

Ripeness. The glycemic index of fruits like bananas goes up as they ripen.

Other foods eaten at the same time. Bring down the overall glycemic index of a meal by combining a high-glycemic index food with foods that have lower ones.

Your age, how active you are, and how fast you digest food also affect how your body reacts to carbs. If you have a diabetes complication called gastroparesis, which delays your stomach from emptying, your body will absorb food much more slowly.

 

The Bigger Picture: Glycemic Load and a Good Diet

The glycemic index shouldn't be the only thing you consider when making choices about what to eat. The fact a food has a low glycemic index doesn't mean it's super-healthy, or that you should eat a lot of it. Calories, vitamins, and minerals are still important.

For example, potato chips have a lower glycemic index than oatmeal and about the same as green peas. But oatmeal and green peas have more nutrients.

Portion sizes matter, too. The more of whatever kind of carbs you eat, the more they'll affect your blood sugar. That's what the glycemic load tells you. It's a number you may see along with the glycemic index in lists. Think of it as the glycemic index for a specific amount of that food.

Is This Normal? Get the Facts Fast!

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70-130
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If the level is below 70 or you are experiencing symptoms such as shaking, sweating or difficulty thinking, you will need to raise the number immediately. A quick solution is to eat a few pieces of hard candy or 1 tablespoon of sugar or honey. Recheck your numbers again in 15 minutes to see if the number has gone up. If not, repeat the steps above or call your doctor.

People who experience hypoglycemia several times in a week should call their health care provider. It's important to monitor your levels each day so you can make sure your numbers are within the range. If you are pregnant always consult with your health care provider.

Congratulations on taking steps to manage your health.

However, it's important to continue to track your numbers so that you can make lifestyle changes if needed. If you are pregnant always consult with your physician.

Your level is high if this reading was taken before eating. Aim for 70-130 before meals and less than 180 two hours after meals.

Even if your number is high, it's not too late for you to take control of your health and lower your blood sugar.

One of the first steps is to monitor your levels each day. If you are pregnant always consult with your physician.

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