Meal planning is often called a cornerstone of diabetes management, but there are many ways to plan a meal, and not all of them will help to keep blood glucose levels in target range. Among those that will is carbohydrate counting, and when the glycemic index of carbohydrate-containing foods is also taken into account, the results may be even better.
Carbohydrate counting involves identifying which foods contain carbohydrate, then assessing how much carbohydrate a serving of food (or an entire meal) contains. For some people, the next step is to match the premeal insulin dose with the amount of carbohydrate. Accurately counting the amount of carbohydrate in your meals can help with blood glucose management, because carbohydrates (with the exception of fiber) raise blood glucose levels. However, some forms of carbohydrate raise blood glucose levels more and faster than others. This is where the glycemic index comes in.
The glycemic index of a food is a ranking (from 0 to 100) of how much it raises blood glucose level after it is eaten. A number of things affect a food’s glycemic index, including the type of starch it contains, the type of fiber it contains, and how finely milled or broken down the grain kernels, beans, or seeds are. Luckily for consumers, lists of commonly consumed foods and their glycemic index values are readily available.
The glycemic load of a serving of food puts together its carbohydrate content and its glycemic index to give a more accurate estimate of how much it will affect blood glucose level. Once you know a food’s glycemic index and the carbohydrate content of the amount you plan to eat, it’s fairly easy to calculate your portion’s glycemic load.
Foods and beverages that contain carbohydrate include bread, cereal, pasta, grains, dried beans and lentils, potatoes, corn, peas, milk, yogurt, fruit, juices, sweets, sugary beverages, and desserts. Packaged foods list the total grams of carbohydrate per serving in the Nutrition Facts panel on the label. The carbohydrate content of nonpackaged foods (such as fresh fruits and vegetables) can be found on numerous Web sites and in many books. (Some examples of books are The CalorieKing Calorie, Fat & Carbohydrate Counter, and The Diabetes Carbohydrate & Fat Gram Guide, published by the American Diabetes Association.)
The amount of carbohydrate found in menu items at chain restaurants can usually be found on the restaurant Web sites (such as www.subway.com or www.applebees.com) or on some general health Web sites such as www.dietfacts.com and www.sparkpeople.com. A variety of free apps for smart phones, iPads, iPod touches, and tablets also list carbohydrate grams in thousands of foods, including restaurant meals. Some examples include MyFitnessPal, Diet and Food Tracker by SparkPeople, and Calorie Counter by Fat Secret.
The total carbohydrate listed on food packages (and on Web sites, in books, etc.) is the sum of starches, added sugars, natural sugars, and fiber. Since the nutrition information is listed “per serving,” the carbohydrate gram information will need to be adjusted accordingly if more (or less) than one serving is eaten. Since fiber is not absorbed by the body and is therefore not broken down to glucose, the grams of dietary fiber can be subtracted from the total carbohydrate for a more accurate estimate of how the portion of food will affect blood glucose level.
Most people need between 30–75 grams of carbohydrate per meal and 15–30 grams for snacks. The amount depends on a person’s age, activity level, sex, health status, and weight. You will want to work with a registered dietitian to determine your carbohydrate targets at each meal and snack.