The glycemic index is a rating system of a particular food's effect on blood sugar levels. A food's glycemic index can determine whether it will cause a sharp increase followed by a drop in blood sugar levels, or if it will promote a steady blood sugar level. The glycemic index can be useful for diabetics, or people on a low-carbohydrate diet.
Identification by Glycemic Index
When a food's glycemic index is determined, its effect on blood sugar is compared to a baseline and given a rating. This baseline is often white bread or glucose. A food's glycemic index can fall into the category of high, medium or low. A food with a high glycemic index tends to rate higher than 70, according to the University of Wisconsin. Medium glycemic index foods rate between 50 and 70, while a food is considered low on the glycemic index if it rates less than 50.
Function of the Glycemic Index
The glycemic index, or GI, can be a useful tool for people watching the amount of carbohydrates in their diet. These include diabetics, those with high triglycerides or people with high cholesterol. For meal planning purposes, the glycemic index can be used to balance high GI foods with those lower on the scale. According to MayoClinic.com, diabetics may use the glycemic index to avoid or reduce diabetic medication needs, and to establish a guideline for expected blood sugar levels throughout the day. However, it can have potential drawbacks.
Misconceptions About the Glycemic Index
GI can only be calculated for foods that contain carbohydrates. In addition, a food's glycemic index does not necessarily indicate how healthy it is. Foods with a low GI may still contain excessive calories and saturated fats, and healthy foods may have a higher GI than expected. In addition, portion sizes do not affect a food's GI. A double serving of a low GI food could potentially bump it into the medium category. In addition, a food's glycemic index may vary based on how ripe it is, or how it is prepared.
Using the Glycemic Index Wisely
A food's glycemic index is affected by the amount of fiber it contains, as well as how processed it is. While it is not necessary to eliminate all high GI foods from the diet, the glycemic index can be a useful guide when it comes to menu planning. Heart-healthy foods often have a low GI, and include such items as beans and legumes, nuts and vegetables. Increasing these foods in the diet can help a person stay full while keeping blood sugar levels in check. In addition, balancing high GI foods with lower ones can prevent excessive spikes in blood sugar levels.
Other Considerations
While the glycemic index can be a helpful resource for diabetics, MayoClinic.com warns against using it alone to plan menus for associated health conditions. The GI ranking system can be confusing, and may not be enough to keep blood sugar levels in check. The American Diabetes Association recommends consulting a dietitian, and using the GI along with more traditional methods such as carbohydrate counting.
