Using carbohydrate counting in diabetes clinical practice.

Carbohydrate counting is a meal planning approach used with clients who have diabetes that focuses on the total amount of carbohydrate eaten at meals and snacks. As 1 of 4 meal planning approaches used in the Diabetes Control and Complications Trial (1), carbohydrate counting has received renewed interest in recent years. Carbohydrate counting can be easy to use for clients and professionals and allows variety in food choices to fit a person's preferences and lifestyle (1). The primary premises of carbohydrate counting are that carbohydrate found in foods is the primary nutrient affecting postprandial blood glucose levels (2-5) and that careful attention to carbohydrate quantity and distribution can improve metabolic control.

HISTORICAL BACKGROUND

Carbohydrate counting is not a new concept. Soon after the discovery of insulin in 1921, references appeared in the literature (6-8) that indicate that carbohydrate counting was used in meal planning for persons with diabetes in the United States and in Europe. Joslin et al (6,7) reported tests in which they administered similar amounts of different carbohydrate-containing foods to compare dextrose to starches. No statistical differences were found in glycosuria or blood glucose using the various test meals. The "total glucose" value of carbohydrate, protein, and fat was figured to be 100%, 58%, and 10%, respectively (6-8). Foods were grouped according to their carbohydrate content; fruits and vegetables each included several categories based on percentage carbohydrate. Calculations of positive and negative carbohydrate balance were made according to the difference between total carbohydrate intake and glycosuria during a test period. If the dietary carbohydrate exceeded the amount of glucose in the urine, the subject was thought to be in positive carbohydrate balance. Ultimately, the total glucose value of the diet was used to determine the necessary dose of insulin (7).

Dietetics curriculums, however, have not focused on the meal planning approach per se. Rather, dietetics and other health care curriculums have taught the exchange system as the standard meal-planning tool for persons with diabetes. This has resulted in the exchange system being perceived as "the diabetic diet" or "the American Diabetes Association diet." The first exchange lists were published in 1950 to provide a structured system based on grouping foods with similar distributions of carbohydrate, protein, and fat so that foods within a group could be exchanged (9). The 1976, 1986, and 1995 revisions of the exchange lists have shown increasing emphasis on carbohydrates. The 1995 lists state that starch, fruit, and milk choices are interchangeable and add another group - other carbohydrates - which includes some sugar-containing foods not mentioned in previous exchange lists (10). For years, consistency of carbohydrate has been a central concept in meal planning for persons with diabetes, including the exchange system for meal planning.

 
FIG 1. Formula for figuring grams of carbohydrate or carbohydrate 
choices from information about carbohydrate sources. 
 
(grams of carbohydrate                     =        grams carbohy- 
serving size on label [or in                        drate in your 
reference book] x your serving                      serving 
size)/serving size on label 
 
Example from cereal box 
 
(26 g carbohydrate on label            = 52/1.25    = 41.6 or 42 g 
x2 c serving size)/1.25 c                           carbohydrate in 
serving size on label                               your serving 
 
42 g carbohydrate [divided by] 15 g        =        2.8, or round up 
(amount in 1 carbohydrate                           to 3, carbohy- 
choice)                                             drate choices 

PRACTICE PATTERNS AND MEAL PLANNING APPROACHES

Practice patterns of dietitians in the United States are changing as a variety of meal planning approaches for persons with diabetes are available and are being used (9). During the past decade, several surveys of dietitians who provide medical nutrition therapy for persons with diabetes have been conducted to determine current practice patterns as well as to assess the needs of dietitians (11-13). These surveys identified the need for a variety of meal planning approaches to be used in addition to the most widely used method, the exchange system. Thus, in 1993, The American Dietetic Association and the American Diabetes Association Steering Committee on Diabetes Nutrition Resources recommended the development and publication of 5 new nutrition resources for diabetes meal planning (13). Carbohydrate counting was 1 of the 5 approaches described in these resources.

In October 1996, the Diabetes Care and Education dietetic practice group offered a skills development workshop on carbohydrate counting at the 79th Annual Meeting and Exhibition of The American Dietetic Association. The session, which was limited because of the requirements of a hands-on, interactive workshop that included a food lab, was sold out. The dietetic practice group conducted a pre-workshop survey of practice patterns of the workshop participants. A profile of the 200 workshop attendees indicated that 95% were registered dietitians and 16% were certified diabetes educators.

By specialty, the participants included generalists (64%), diabetes nutritionists (18%), and other (18%). Practice settings included hospital inpatient (31%), private practice (19%), hospital outpatient …