You may have heard the term "glycemic index" (GI) tossed around by your healthcare provider, but not know exactly what it is. The GI measures how foods that contain carbohydrates raise your blood sugar, according to the American Diabetes Association. Foods with a high GI raise the blood sugar more than foods with a low or medium GI. It takes a little while to get the hang of knowing which foods will raise your blood sugar quickly (and thus have a high GI), but once you are used to the system, it all makes sense.

"Carbohydrates are the main staple for many people," explains Gladys Ramos, RN, CDE, who works at the William F. Ryan Community Health Center in New York City. "Carbs raise the blood sugar, so people really need to be educated. It's a real mind change for many people who are used to eating carbs whenever they want." The GI can make it easier to know how quickly a food will raise your blood sugar.

Many people aren't sure what constitutes a carb or how many grams of carbohydrate a particular food may have, says Rory Breidbart, MD, chief of the division of endocrinology at St. Francis Hospital in Roslyn, New York.

"Where most people fall apart is underestimating the number of carbs they are eating, the same way most people underestimate the number of calories they are eating," Breidbart explains. "People don't always understand the glycemic load of a food."

If your health care provider wants you to use the GI when choosing foods, you'll most likely be told to combine foods with a high GI with foods that have a low GI in order to balance out the meal, according to the American Diabetes Association.

Among the foods that have a low GI are non-starchy vegetables, some of the starchy vegetables, most fruits, all-bran cereals, and dried beans and legumes. Foods with a high GI include white bread and white pasta, plus pastries, muffins and white potatoes. Fats and meats don't have a GI since they don't contain carbohydrates.

If you're wondering what affects the GI of a food, keep in mind that both fat and fiber tend to lower the GI, according to the American Diabetes Association.  

Here are some factors that affect a food's GI:

● Cooking and processing. In other words, juice has a higher GI than fruit, while a mashed potato has a higher GI than a baked spud.

● Cooking method: The longer the cooking, generally the higher the GI. Soft cooked pasta has a higher GI than pasta cooked al dente.

● Ripeness and storage time: the riper the produce, the higher the GI.

Don't necessarily assume that a low GI makes a food healthy. For instance, oatmeal has a higher GI than chocolate. Whether or not the GI works better than carbohydrate counting when planning meals is a matter of personal preference, according to the American Diabetes Association. The important thing is to work with your health care provider to tailor a meal plan that works for you.