Information about carbohydrates and your diet abounds, including advice regarding which carbohydrates are good or bad for you based on glycemic index. Carbohydrates are an important part of a healthy diet, but it is important to choose wisely. The association of glycemic index with weight control and prevention of chronic disease makes it a significant factor in deciding what to eat.
Definition
Glycemic index is a measurement of how much a specific food impacts your blood sugar and insulin levels compared with pure glucose, which has a glycemic index of 100. Foods with a glycemic index of 55 or less have a low glycemic index, and those with a score of 70 or more have a high glycemic index. High-glycemic-index foods cause a sharp spike in blood sugar, necessitating a large release of insulin by the pancreas to bring blood sugar back to normal. Foods with a low glycemic index have a slower, steadier effect on your blood sugar and insulin response.
Significance
If your diet frequently includes high-glycemic-index foods, the sharp, rapid increase in blood sugar that results may put you at increased risk for weight gain, type 2 diabetes, heart disease, macular degeneration and colon cancer. More evidence is needed, but in the meantime, it's wise to choose foods with a low glycemic index, according to the Harvard School of Public Health.
Factors That Affect Glycemic Index
The main factor affecting a food's glycemic index is how much it's been processed, or changed from its natural state. Other factors are a food's fiber, fat and protein content, and whether it's eaten alone or along with other foods. Grains that are processed -- ground, milled and sometimes bleached -- are mostly starch because they're stripped of their hulls and germ, leaving them lower in fiber and leading to spikes in blood sugar.
High-Glycemic-Index Foods
Foods made from highly-processed and refined grains -- white bread and bagels, hamburger buns, most ready-to-eat breakfast cereals, plain microwave popcorn, pizza, flour tortillas and pretzels -- have a high glycemic index. So do foods high in added sugar, such as candy, sugary soft drinks, cookies and other desserts. Natural foods with a high glycemic index include white potatoes, parsnips, dates and raisins.
Low-Glycemic-Index Foods
Most fruits and vegetables, whole grains and beans have a low glycemic index and are rich in nutrients, too. Go for oatmeal, barley, brown rice, bulgur and all-bran cereals. Choose bread, bagels, tortillas and crackers made with whole grains. Read food labels and look for whole grains listed as the first ingredients. Avoid those listing enriched, refined or unbleached flour, or plain wheat flour -- instead of whole-wheat flour -- as the first ingredients, according to the IDEA Health and Fitness Association.
