Carbohydrates used to be categorized as simple or complex, but now the glycemic index, or GI, is the gold standard for evaluating carbohydrate quality. The GI is the best way to predict the impact of carbohydrate-containing foods on blood sugar levels in the hours following their consumption. High GI foods, with a GI value of 70 or higher, results in large blood sugar levels spike after eating, while low GI foods, with a GI of 55 or less, are associated with a smoother and smaller rise in blood sugar concentrations.
Measurement of the Glycemic Index
The glycemic index is measured by feeding a serving of food containing the equivalent of 50 g of available carbohydrates to at least 10 healthy volunteers. Their blood sugar levels are monitored during the following two hours and compared against their blood sugar response resulting from the consumption of 50 g of pure glucose. For example, if the average glycemic response obtained after eating apples corresponds to 34 percent of the glycemic response obtained with glucose, the GI score attributed to apples will be 34.
Eggs
Eggs do not have an assigned GI value. A large egg contains 0.4 g carbohydrate and in order to measure the GI of a food, participants have to consume a serving equivalent to 50 g of available carbohydrate, which would correspond to eating approximately 125 eggs. For this reason, the GI of eggs cannot be measured, whether eggs are hard-boiled, fried, poached or scrambled.
Foods Without a Glycemic Index
Other foods, such as eggs, do not contain enough carbohydrates to have their GI tested. These foods include meat, poultry, fish, avocados, salad vegetables and cheese. Like eggs, these foods, even when consumed alone and in large quantities, are not likely to significantly impact blood sugar concentrations, as explained in the international table of glycemic index and glycemic load values published in 2002 in the "American Journal of Clinical Nutrition."
Glycemic Index and Health
Including hard-boiled eggs as well as other foods with low GI values to your diet is likely to help you maintain your blood sugar levels more stable throughout the day. Keeping your dietary GI low is associated with a reduced risk of developing cardiovascular disease, Type 2 diabetes and obesity, in addition to helping you feel less hungry and improve your physical and athletic performances.
References
- Harvard Health Publications: Carbohydrates and Health: Not that Simple...or that Complex
- University of Sydney: The Glycemic Index
- "American Journal of Clinical Nutrition"; International Table of Glycemic Index and Glycemic Load Value; Kaye Foster-Powell et al; 2002
- USDA National Nutrient Database: Nutrient Data Laboratory
