The glycemic index is a way to tell how quickly foods that contain carbohydrate may raise your blood sugar.

On a low glycemic diet, you eat foods that raise your blood sugar slowly. This helps you keep your blood sugar from getting too high. This diet plan is sometimes called a "low GI" diet.

• Low glycemic foods break down slowly in your body and release sugar into the blood slowly.
• High glycemic foods break down quickly and make blood sugar rise quickly.

In general, carbohydrate raises blood sugar more quickly than other nutrients like proteins and fats. But some foods that have carbohydrate raise blood sugar more slowly than other foods with carbohydrate. For example, white bread raises blood sugar more quickly than whole-grain bread.

Foods in the index are given a number from 0 to 100. The higher the number, the higher the glycemic index. Foods are compared to glucose, which is sugar. It has a rank of 100.

• Foods that raise blood sugar quickly are high. They are rated 70 or more.
• Foods that raise blood sugar moderately are medium. They are rated 56 to 69.
• Foods that raise blood sugar slowly are low. They are rated 55 or less.

The glycemic index of a food can change depending on the variety of the food (for example, red potato or white potato), its ripeness, how it is prepared (for example, juiced, mashed, or ground), how it is cooked, and how long it is stored.

Most of the carbohydrate-rich foods that you eat on this plan should be low or medium on the index. A dietitian or certified diabetes educator can help you pick foods that you like that are low on the index. You also can look at materials from the American Diabetes Association or go to its website at www.diabetes.org.

People respond differently to the glycemic content of foods. And because many things affect the glycemic index, the only way to know for sure how a food affects your blood sugar is to check your blood sugar before and after you eat that food.

High-glycemic foods are rarely eaten by themselves, so the glycemic index might not be helpful unless you're eating a food by itself. Eating foods together can change their glycemic index.

Choosing a low glycemic diet doesn't mean that you can't eat any high glycemic foods. Some high glycemic foods, such as potatoes, have lots of nutrients. Just try to limit how much of these foods you eat.

You should combine a low glycemic diet with another eating plan for diabetes, such as carbohydrate counting. The glycemic index can help you know the kind of carbohydrate you're eating. Carbohydrate counting can help you know how much carbohydrate you're eating. For more information on carbohydrate counting, see:

Diabetes: Counting Carbs If You Don't Use Insulin.

Continue to Why?

People who have type 2 diabetes need to use diet and physical activity to keep their blood sugar under control. Some people who have type 2 diabetes also need to take medicine.

Carbohydrate raises blood sugar more than any other nutrient. So eating carbohydrate that raises blood sugar slowly is one way to help keep your blood sugar under control. Well-controlled blood sugar lowers your chance of getting problems from diabetes that can affect your heart, eyes, nerves, and kidneys.

The best way to keep your blood sugar under control is to count how much carbohydrate you're eating and to spread carbohydrate foods throughout the day.

Most foods that have carbohydrate also contain protein or fat, or both. But the protein and fat aren’t ranked in the glycemic index, because they don’t raise blood sugar like carbohydrate does.

Continue to How?

You don't have to deny yourself certain food groups or favorite dishes when you follow a low glycemic eating plan. You focus on eating measured amounts of low or medium glycemic foods and trying to eat a balanced diet.

Write down what you eat now

The first step is to look at the kinds of foods you're eating now. Write down(What is a PDF document?) the carbohydrate-rich foods you eat over several days. Then find the glycemic index of these foods and list them under columns labeled low, medium, or high. You can see at a glance how many high, medium, and low glycemic foods you eat.

You may find that you already are eating many foods that are low or medium on the index. But you also may find many foods that are high glycemic or on the high end of medium.

Swap some high glycemic foods with low choices

Look at your diary for high glycemic foods that you eat only now and then or that you wouldn't mind removing from your diet.

Find some low glycemic choices that you could eat in place of those high glycemic foods. The following are some examples. If you like baked potatoes, try having a baked yam instead. If you often eat a plain bagel for breakfast, try a slice of multi-grain toast instead. Watermelon is a fine treat once in a while in the summer. But you could limit how much of it you eat. Or you could have strawberries or other low glycemic berries instead.

Follow some tips to make low glycemic choices

• Eat unprocessed food as often as you can. Whole, unprocessed food usually (but not always) has a lower glycemic index than the same food when it's processed. For example, white bread is more processed than whole wheat bread.
• Don't overcook pasta. Cooking pasta until well done raises its glycemic index. For a lower glycemic index, pull the pasta out of the water when it's still a little firm—but not hard—when you bite it.
• Choose high-fiber foods. Most food that is high in fiber takes longer to digest and raises blood sugar slowly.
• Eat measured portions of high glycemic foods. You can still eat food with a high glycemic index. Many of these foods have nutrients that you need. But try to eat small portions.
• Eat a low glycemic food along with a high glycemic food. The low glycemic food will help counter the effect of the high glycemic food, so your blood sugar may rise more slowly. Adding a healthy fat to your meal also will slow the rise of your blood sugar. For example, add a small amount of olive oil when you roast potatoes. Although sticky rice has a high glycemic index, eating it with chicken and vegetables will lower its glycemic index.
• Choose whole grains. Use whole-grain bread for your toast in the morning, and eat whole grains at lunch. Whole grains include barley, brown rice, and 100% whole wheat bread.
• When eating out, choose dishes with vegetables. Most vegetables are low on the glycemic index.

Set goals and get support

• Have your own reasons for wanting to try this eating plan.
• Set a main goal. Then start with smaller goals that will help you reach your larger goal. For example, if your main goal is to eat only one high glycemic food a day—and you now eat seven high glycemic foods a day—you could make a smaller goal to remove one or two of those high glycemic foods from your diet each week.
• Think about what might get in your way. Know that you may have slip-ups, and prepare for how you'll deal with them. Perhaps you went out to eat and had a meal with several high glycemic foods. Instead of being upset with yourself, you could try to make a plan for the next time you go out to eat. You might be able to look at the menu online beforehand. That way, you can pick low or medium glycemic foods ahead of time.
• Get support as you make a change in your diet. Ask friends or family to encourage you. They might even want to join you in eating more low glycemic foods.

Continue to Where?

Now that you have read this information, you can start looking for low glycemic foods to substitute for high glycemic foods.

Talk with your doctor. If you have questions about this information, print it out and take it with you when you visit your doctor. You may want to mark areas or make notes in the margins where you have questions.