Carbohydrate provides a large portion of the daily calories in the American diet. Carbohydrate includes starches, sugars and fiber and are mainly found in grain products, potatoes, legumes, milk, yogurt, fruit, juices, soft drinks and sugar. Some carbohydrates are healthier than others by providing important nutrients such as fiber and antioxidants and by helping to regulate blood sugar levels. The glycemic index, or GI, is the best available tool to determine the quality of carbohydrate-containing foods.
Glycemic Index Overview
The glycemic index was developed to assess the impact of foods containing carbohydrates on blood sugar levels. Blood sugar levels peak higher following the consumption of high GI foods, characterized with a GI of 70 or more; while they are steadier and more stable after eating low GI foods, characterized with a GI of 55 or lower.
Bagels Vary on the Glycemic Index
The "International Table of Glycemic Index and Glycemic Load Values" only list the glycemic index value for white bagels, which corresponds to 72. This value falls within the high GI food category. However, whole grain bagels do not cause a sharp increase in blood sugar because they're slightly higher in protein and contain twice the fiber, making it a lower glycemic swap with a plain white bagel, according to GI Listing, an online glycemic index database.
Bagels Glycemic Load
The glycemic load, or GL, is another concept that can help determine the impact of carbohydrate-containing foods on health. The GL is calculated by multiplying the GI of a food by the amount of available carbohydrate present per serving, divided by 100. A GL below 10 is low; between 11 and 19 is medium; and above 20 is high. Available carbohydrates represent the amount of carbohydrates able to influence blood sugar levels and are calculated by subtracting fiber from total carbohydrates. A medium-sized bagel with a diameter between 3.5 inches and 4 inches, contains 56 g of carbohydrates and 2.4 g of fiber, which corresponds to 53.6 g of available carbohydrates. Therefore, a white bagel of that size has a GL of 38.6, which is considered high.
Glycemic Index and Health
Foods with a high glycemic index are associated with overweight and obesity and an increased risk of suffering from type 2 diabetes and heart diseases, whereas a diet based on low glycemic carbohydrates results in a healthier body weight, a lower risk of developing heart disease and better glycemic control for people living with diabetes.
References
- University of Sydney: The Glycemic Index
- "American Journal of Clinical Nutrition"; International Table of Glycemic Index and Glycemic Load Values; Kaye Foster-Powell, et al.; 2002
- Harvard School of Public Health: Carbohydrates: Good Carbs Guide the Way
- Harvard School of Public Health: Glycemic Index and Glycemic Load for 100+ Foods
- GI Listing.com
