All carbohydrates (carbs) are not created equal, so counting carbs alone may not show the whole picture. Some carbohydrate-containing foods can cause a faster rise in blood sugar levels than other foods. Using the glycemic index may be a helpful way to identify and compare how different foods can impact blood sugar.
The glycemic index (GI) is a measurement of how much one kind of food will raise blood sugar levels. The theory is that a food with a low glycemic index will cause a small and slow rise in blood sugar level, while a food with a high glycemic index will cause blood sugar to rise more quickly.
The glycemic index (GI) is based on glucose, the carbohydrate that raises blood sugar the fastest. Glucose has a rating of 100. Foods are divided into 3 categories: high GI, medium GI, and low GI. They are ranked on how they compare to glucose.
When planning meals, it can be useful to try and choose foods that have a low or medium GI. If a meal does include a food with a high GI, try to eat a smaller portion.
High GI foods have a GI of 70 or more. Some examples are:
- White bread
- Potatoes (boiled)
- White rice (boiled)
- Glucose (sugar)
Intermediate or medium GI foods have a GI between 56 and 69. Here are some examples:
- Sweet potatoes (boiled)
- Pineapple (raw)
- Potato chips
Low GI foods have a GI of 55 or less. Some of these are:
- Mixed-grain breads
- Legumes (such as chickpeas, beans, and lentils)
- Milk and yogurt
- Ice cream
Other things to keep in mind when using the glycemic index:
- While the GI indicates what type of carb a food contains, it does not take into account how many carbs are being eaten. So it is still necessary to pay attention to portion sizes
- Combining foods with different GIs may help balance out their effect on blood sugar
- Nutritious foods can still have a high GI, while foods with little nutritional value may also have low GI. For example, chocolate has a relatively low glycemic index (40), but its high saturated fat content reduces its nutritional value
- While the GI can be a helpful way to compare or rank food choices, there is some debate as to how accurate or useful it is for blood sugar control. So before changing what you eat based on the GI, talk to your health care provider about how it may (or may not) be helpful for your diabetes care plan