The food exchange lists for medical nutrition therapy (MNT) education are the grouping of foods into general categories that are similar in macronutrients and calories per serving size. The 2nd edition of the Food Exchange Lists for People with Diabetes developed by the Korean Diabetes Association, the Korean Dietetic Association, and the Korean Nutrition Society had six food categories (starch, meats, vegetables, dairy, fruits, and fats), and for each category, foods of similar exchange units can be freely exchanged and consumed [1]. This exchange lists have been used not only as educational tools for diabetes but also as a method for managing obesity and other chronic diseases.

The first edition of South Korea's food exchange lists were developed in September 1987 by the Korean Diabetes Association, the Korean Dietetic Association, and the Korean Nutrition Society through a joint research effort to make food categories and quantify exchange units for each food category. In 1993, modification of exchange unit in some food products and aesthetic corrective action for food samples was taken. The 2nd edition of Korean Food Exchange Lists and Guidelines were revised in 1995 [2]. However, the recent dietary pattern and intake in South Korea is rapidly changing due to economic growth, westernized lifestyles and the development of food processing technology. Personalized education that considers individual dietary preferences and pattern is currently increasing in popularity as the importance of individualized MNT is becoming better recognized. So, the supplement or revision of the food exchange lists for Korean diabetic patients, that reflects a proper diet and also encourages willpower for proper eating habits, is needed. Although the food exchange lists are useful tools for adjusting the amounts of food intake and its macronutrient composition in patients with diabetes, but there were several reports that understanding the concept of food exchange lists and practicing it is difficult in patients with lower education [3]. Thus demand for improvements to the food exchange lists is also rising.

In the United States, the American Diabetes Association (ADA) and the American Dietetic Association jointly issue educational materials and revise the food exchange lists for patients with diabetes. These lists were revised in 1995 to include the carbohydrate counting [4]; in later editions, the presenting food products were enlarged to reflect recent changes of dietary pattern, development of new foods, individual dietary habits, and diverse food preference. To simplify the usage, some food categories were changed, the Plant-Based Protein list was add in the Meats and Meats Substitutes category and mixed foods and fast foods lists, and alcohol lists were added in 2008. In addition, some foods were deleted, and other new foods were added after reflecting the recent nutritional recommendations and guidelines, the survey response from diabetes educators, and the food market survey [5], and the total of over 700 foods were represented. In Japan, educators are using a varied food exchange system instead of a unified food exchange lists. The Japanese Diabetes Society used a scoring method that matched one food exchange unit to 80 kcal for the convenient calculation of caloric intake.

As a preliminary work for the revision of the food exchange lists for Korean patients with diabetes, the Food and Nutrition Committee of the Korean Diabetes Association made a survey sent to diabetes educators, physicians, and patients with diabetes to evaluate food exchange lists options in March of 2008.

In this study, diabetes educators pointed out difficulties in using the food exchange lists as an educational tool. It was consistent with results of 2001 survey of dieticians from Seoul Metropolitan area regarding awareness and revisions to the food exchange lists, 39% of the dietitians felt that using the food exchange lists was difficult, 26% felt that it was too complex, and 23% said that it was confusing for patients with diabetes [6]. To better understanding of exchange lists, 88% of the participants felt that the lists should be amended or at least partially modified. The American Dietetic Association recommends the food pyramid in the initial education, the exchange lists and the carbohydrate counting in the subsequent education for the effective MNT according to the stage of education. Nurss et al. [7] reported that the educational content from the food exchange lists was difficult to understand, particularly in patients with a lower level of education. Therefore, a method should be developed to divide the food exchange lists into the following steps: 1) initial stage food exchange lists (varied foods from each food group, introducing starch and free foods); 2) intermediate step food exchange lists (recommended calories, nutrients and one exchange reference unit per food group, and basic concept of carbohydrate counting) for subsequent education; 3) late-stage food exchange lists (advanced carbohydrate counting, and introducing the glycemic index) for intensive education.

The food exchange lists was revised in 1994; in order to reflect changes that have taken place since then, new foods should be added to each food group to fit current dietary habits. Even with similar types of foods, one exchange unit may vary according to the size and variety of food, and confirmation of the reference equivalent of one exchange unit is required.

When the trends of the Korean National Health and Nutrition Examination Survey were examined [8,9], they found that carbohydrate consumption has been steadily decreasing since 1969, while average daily meat and dairy amounts consumed per day increased from 6.6 g and 2.4 g, respectively, in 1969 to 93.9 g and 90.2 g in 2007. Beverage and alcohol consumption also increased nearly 1.5-fold from 94.2 g in 1998 to 154.3 g in 2007, particularly beer and Soju, which accounted for the fourth and fifth most consumed food. A dietary pattern survey from 2005 revealed that 40% of teenager and young adults do not eat dinner with their families, and a survey from 2007 found that the higher income families tended to eat together less often and were more likely to eat snacks and eat out. Another study that analyzed the Korean National Health and Nutrition Examination Surveys from 1998 and 2001 found that as economic status increased, the consumption of Kimchi declined while noodle/dumpling-like food consumption increased [10]. In the study presented by Song et al. [11], younger age, higher educational level and annual income, and larger city size were associated with a higher consumption of noodles, bread, fast foods, meat, dairy, and sugary beverages. Additionally, in this study, we found that participants most often suggested the addition of free food that patients could eat without raising blood sugar, as well as snacking/dining out options. The comparative free foods, such as clear vegetable soups, seaweed, low-sugar vegetables, and drinks such as black tea, green tea, and diet cola were proposed for the nutritional education program; a list of low-sugar vegetables and a clear and varied method for identifying existing types of free foods, drinks and spices that can be added are also required. Additionally, a standardized way by which to measure food consumption is needed in terms of sugar content so that changes in blood glucose level do not occur. The addition of food amounts of each group on the food exchange lists is important in order to enable patients to select foods that are easily accessible in everyday life. In order to expand the current food exchange lists to include various snacks, restaurant foods, high alcohol consumption, and so on, that do not fit into the current six existing food groups, the nutritional information for these items must be reviewed.

In the results of this study, the food exchange lists was used most often as an educational method. However, 10.9% of educators stated that carbohydrate counting was being used in combination with the exchange lists. In 2005, survey reports from 25 hospitals showed that 11 of these hospitals were using the carbohydrate counting, 8 hospitals were using carbohydrate counting as an educational method and 7 were using it according to the type of patient and their education level. The carbohydrate counting is gradually developing interest and is being applied based on patient's education level and educational goals in a basic course (eating a certain amount of carbohydrates at set times every day with set snack distribution) and an advanced course (adjusting insulin dose according to the amount of carbohydrates consumed; calculating the glucose to insulin ratio) [12,13]. The United States revised the fourth edition of their food exchange lists to include the carbohydrate counting in a new food exchange lists system. One exchange unit from the grain, fruit, dairy or other carbohydrate group is treated as one serving size (15 g) so that foods from these groups can be interchanged. However, in the Korean food exchange lists system, the nutrient content among grain, dairy and fruit groups is different; therefore, they cannot easily be exchanged. In addition, the one serving size of carbohydrate should be standardized to exchange, but each hospital uses different serving size, which makes the system confusing. In South Korea, the carbohydrate content of various carbohydrates must first be properly quantified before the carbohydrate counting can be successfully implemented. Additionally, standardized educational materials and guidelines for the carbohydrate counting should be prepared.

In this study, 64.6% of educators replied that "The reflection of glycemic index of carbohydrate group" was a field that required supplements. The glycemic index reflects the specific foods' postprandial glucose absorption rates compared with standardized food. The 2008 ADA recommends using the glycemic index while also maintaining a constant total consumption of carbohydrates through a supportive method of controlling blood sugar [14]. The glycemic index lists of various foods that have been published in other countries are difficult to apply to Korean foods. To correct this problem, it is needed to provide applicable glycemic index through the progress of domestic studies about the glycemic index. Additionally, when a glycemic index is being used, factors affecting it (carbohydrate structure, fiber content, preparation/production process, maturity of the food, storage conditions, presence of digestive enzyme, simultaneous intake of proteins or lipids, and so on) should be considered. The fact that the glycemic index of a food product can vary based on the person and individual circumstances must be considered. Use of the glycemic index only recognizes the benefits and downsides to certain foods, and in order to prevent destructive dieting patterns, current nutritional education programs need to always emphasize the value of a balanced diet while also confirming that patients have an accurate understanding of the advantages, disadvantages and application methods of the glycemic index.

In conclusion, our survey found that the majority of the diabetes educators used the food exchange lists as a tool for nutritional education. The results also showed that most participants felt that a revision or supplement to the food exchange lists was required. These respondents suggested that these supplemental items include the glycemic index of carbohydrate foods, the addition of new foods and the confirmation of an exchange reference unit. In the survey results from the diabetic patients, we found a high demand for tips on various free foods and for snacks/restaurant foods. Therefore, to represent the diversity of food, a new food lists should be added, and in order to confirm the one exchange reference unit of each food group and to reflect the glycemic index in the Korean food exchange lists, various evidence and data should be collected. The standardized carbohydrate counting must be arranged based on the revised food exchange lists. In addition, it must compensate for gradually increasing changes in mixed food eating patterns and represent the needs of nutritional education recipients. Nutritional information is also required for various restaurant foods and snacks, and ways to recommend food selection guidelines should also be considered.