Carbohydrates are an essential part of the diet, and the body needs these nutrients in large amounts to fuel its daily activities. Different sources of carbohydrates affect the body's blood glucose levels differently, leading to a substantial difference in the type of energy that food provides. The glycemic index is a helpful tool for measuring a food's effect on blood glucose levels.
Definition
The glycemic index is a ranking of different sources of carbohydrates on a scale of 1 to 100, based on that food's effect on blood glucose levels after consumption. Foods with a high-glycemic index raise blood glucose levels the most immediately after eating them while low-glycemic index foods provide a more gradual rise in blood glucose levels for a longer period of time.
Effects
Food with a high-glycemic index provide instant energy followed by a "crash." Low-glycemic foods, on the other hand, enter the bloodstream more slowly and provide steady, lasting energy throughout the day. Diets comprised of high-glycemic index foods are highly associated with an increased risk of both Type 2 diabetes and coronary heart disease.
High-Glycemic Foods
Foods with a glycemic index of 70 or above are considered high. White bread, bagels and kaiser rolls all have glycemic indexes around 100. Most sugary products and desserts have high-glycemic indexes as well. Doughnuts, angel food cake and pastries typically have glycemic indexes approaching 100. Snack foods such as pretzels, rice cakes and potato-based products have high-glycemic indexes.
Low-Glycemic Foods
Foods with a glycemic index of 55 or below are considered low. Fresh fruits, whole grains and beans have low-glycemic indexes. Barley has a glycemic index of just 36, while chickpeas and kidney beans both have glycemic indexes of 39. Cherries and grapefruit have glycemic indexes under 40, and peas and corn are among the vegetables with the lowest glycemic indexes.
Recommendations
If you are concerned about your cholesterol, cardiovascular risk or chances of developing diabetes, consuming a diet full of low-glycemic index foods may be beneficial. Try to consume fresh foods whenever possible, as canned and packaged foods have added sugars and preservatives that can spike your blood glucose levels. Try to consume raw fruit as opposed to juice to avoid excess sugar. Anything with whole grains and high in fiber typically has a low-glycemic index, and avoid potatoes as much as possible due to their high starch content.
References
- The Glycemic Index
- MayoClinic.com; Glycemic Index Diet; Maria Collazo-Clavell
- Harvard School of Public Health: Carbohydrates
- "Essentials of Strength Training and Conditioning"; Thomas Baechle, et al. (editors); 2008
