The glycemic index is a measure of how different foods affect a person's blood sugar levels. Glycemic index ratings can be helpful for diabetics who need to monitor their blood sugar. Understanding which foods are low on the glycemic index can help diabetics make better food choices; however, it should not be the only tool used.
Calculating a Food's GI
The glycemic index, also called GI, ranks foods based on their effect on blood sugar levels. Their effects are compared with that of a baseline food, which is usually either glucose or white bread. A food with a high GI ranking means it elevates blood sugar levels higher than a food with a lower rating. Foods may also be ranked somewhere in the middle. According to the University of Wisconsin, a food is considered low on the GI scale if it rates less than 50, and medium if it rates between 50 and 70. High GI foods rank 70 and higher.
Significance of Low GI
Foods with a low glycemic index still raise blood sugar levels; however, they raise them slowly and keep them steady over time. This differs from a high GI food, which causes blood sugar levels to rise, peak and fall in a short amount of time. A food's GI ranking does not indicate how high blood sugar levels are expected to rise after eating; it is simply a comparison of carbohydrate-containing foods on a scale from zero to 100.
GI and Diabetes
The glycemic index can be a useful tool for diabetics, as it can help them estimate what their meals will do to their blood sugar levels without having to guess or test more frequently. It can also help them make better food choices. For instance, the American Diabetes Association recommends balancing high GI foods with low GI foods for a more diabetic-friendly meal. In addition, they recommend eating more foods from the low GI categories and limiting those from the high categories.
Examples of Low GI Foods
Some examples of low GI foods are bran cereal and barley, nuts, beans and legumes, fresh fruits and vegetables and dairy products. Noticeably absent from the list are meats and fish. This is because the glycemic index only ranks foods that contain carbohydrates. In general, foods that are higher in fats and fiber are lower on the GI scale, as are fresher foods such as raw vegetables.
Is a Low GI Enough?
MayoClinic.com warns diabetics against relying too heavily on the glycemic index for menu planning. Not all low GI foods are healthy dietary choices, and different food preparation methods can alter its GI. In addition, the ADA warns that GI rankings do not take portion sizes into account. In order to truly eat well for diabetes, the Mayo Clinic and ADA recommend consulting a registered dietitian.
