The exchange system diet is a meal planning tool that groups foods together based on their nutritional similarity. This allows for flexibility and variety in meal planning while maintaining control over macronutrient intake, particularly important for individuals managing diabetes. This article provides a comprehensive overview of the exchange system diet, its principles, and its practical application.
The Basic Principle of the Exchange System
The principle of the exchange system is to group together foods with similar qualities that may provide the same nutritional value when exchanged for one another. Exchange lists or systems are educational tools that have allowed nutrition and dietetic professionals to plan healthy meals without altering the macronutrient or energy content in a fast, practical, and reliable manner according to people’s tastes and habits and that meet nutritional requirements. The exchange lists were originally created for the nutritional management of patients with diabetes, who are required to control their carbohydrate intake (CHO) since the CHO count is used to plan their meals and focuses on estimating the macronutrient content that mainly influences the postprandial glycemic response. However, nowadays the use of the lists has been extended to other metabolic pathologies, such as obesity or cardiovascular diseases. Furthermore, food exchange lists allow experts to consider the reality of each country in order to develop appropriate food guides and nutritional education programs at local and national levels for the prevention and control of diseases.
Core Food Categories in the Exchange System
The exchange system diet typically divides foods into several main categories. In the original exchange-list system, the diet is divided into six major categories. Foods with similar energy and macronutrient content per single serving were grouped. Each food serving was known as an exchange. The major lists are Starch (sometimes called Bread/Cereals), Fruit, Non-Starchy Vegetables, Milk, Meat and Meat Substitutes (sometimes called Protein), Fat (sometimes called Fats/Oil) and Free Foods. In recent versions, another category called Desserts (sometimes called Alternate Carbohydrates or Sweets) has been added.
Here's a closer look at some of the key categories:
Starch
The ‘starch’ category includes food items with predetermined serving sizes that add up to 80 calories, 15 grams of carbohydrates and 3 grams of protein. Examples of starch exchanges may include bread, cereal, pasta, rice, and starchy vegetables like potatoes and corn. Not all bread/starch exchanges are breads.
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Fruit
This category includes fruits and fruit juices.
Non-Starchy Vegetables
Examples include beets, broccoli, cabbage, carrots, cauliflower, cucumber, mushrooms, tomatoes, and zucchini.
Milk
This category includes milk and yogurt. In the late 1970's when there was interest in more clearly describing the saturated fat content of the diet the Milk exchange lists were further subdivided into three levels of fat intake.
Meat and Meat Substitutes (Protein)
Each exchange of a lean protein listed below contains about 7 grams of protein, 0 to 3 grams of fat, and 45 calories. Medium and high-fat proteins have more calories. Some plant-based proteins contain carbohydrates. In the late 1970's when there was interest in more clearly describing the saturated fat content of the diet the Meat exchange lists were further subdivided into three levels of fat intake. Many non-meat foods appear as meat exchanges because of their protein and fat levels.
Fat
This category includes fats and oils.
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Free Foods
The foods on this list are called free foods because they have very few calories. Foods in the Free category in the portion sizes described are generally omitted from calculations since they don't include significant amounts of macronutrients and usually have less than 15-20 kcal per serving. However, clients are cautioned to limit intake to no more than 3 servings spread throughout the day. They are instructed to be cautious because if they consume more than 3 servings together during a meal or snack it may raise blood sugar. The Free group includes many fresh, canned or frozen vegetables that are prepared without additional sauces or fat as well as many condiments (e.g. prepared mustard, low calorie salad dressings). They are not "counted". Limit artificial sweeteners. These may be found in food or drinks, such as diet soft drinks or other low-calorie beverages.
Creating a Personalized Meal Plan
Because everyone’s needs are different, you should talk with a doctor or registered dietitian if you’re diabetic or have pre-diabetes to make sure your personalized daily nutrition goals are on point. One of these diabetes educators can give you your personalized daily goal exchanges for each category. A dietitian will work with you to create a healthy meal plan that is right for you. This meal plan will include the amount of exchanges from each food group each day. Follow your meal plan by tracking exchanges for meals and snacks. Each exchange contains about 12 grams of carbohydrate and 8 grams of protein. Each exchange contains about 5 grams of carbohydrate , 2 grams of protein, and 25 calories.
- First, you’ll need to meet with a registered dietitian nutritionist or a certified diabetes educator to come up with an appropriate meal plan.
- Then, pick your desired foods from each exchange list, paying close attention to serving size.
Practical Tips for Using the Exchange System
- Consult a Professional: Always seek guidance from a registered dietitian or certified diabetes educator to create a personalized meal plan that aligns with your individual needs and health goals. As always, please consult with your dietitian and doctor before starting any kind of diet plan.
- Read Food Labels: Pay close attention to serving sizes and nutritional information on food labels to accurately count exchanges.
- Track Your Intake: Keep a record of your food intake and exchanges to ensure you are staying within your meal plan guidelines.
- Stay Hydrated: Your dietitian or healthcare provider will encourage you to drink water. Water helps your kidneys to function properly.
- Choose Wisely: Choose heart healthy, low fat foods. Ask your dietitian or provider how much fat you should eat each day. Choose foods low in fat, saturated fat, trans fat, and cholesterol. Examples include turkey or chicken without the skin, fish, lean cuts of meat, and beans. Low-fat dairy foods, such as low-fat or fat-free milk and low-fat yogurt are also good choices. Omega-3 fatty acids are healthy fats that are found in canola oil, soybean oil and fatty fish. Salmon, albacore tuna, and sardines are good sources of omega 3 fatty acids. Eat 2 servings of these types of fish each week.
- Limit Sugar and Sodium: Limit sugar. Sugar and sweets must be counted toward the carbohydrate exchanges that you can have within your meal plan. Limit sugar and sweets because they are usually also high in calories and fat. Have less sodium (salt). Limit sodium to 2,300 mg or less per day. You may need to eat even less sodium if you have certain medical conditions.
- Limit Alcohol: Limit alcohol as directed. Ask your provider if it is okay for you to drink alcohol. Your provider can tell you how many drinks are okay for you within 24 hours or within 1 week. Always have food when you drink alcohol. Your blood sugar may fall to a low level if you drink when your stomach is empty. Women 21 years or older and men 65 years or older should limit alcohol to 1 drink a day. Men aged 21 to 64 years should limit alcohol to 2 drinks a day.
- Monitor Blood Sugar: Control your blood sugar level. Test your blood sugar level regularly and keep a record of the results. Ask your healthcare provider when and how often to test it.
- Physical Activity: Get regular physical activity. Physical activity can help lower your blood sugar, reduce heart disease risk, and manage weight. Adults should get at least 150 minutes (2.5 hours) of moderate intensity aerobic activity every week. Spread aerobic activity over at least 3 days, with no more than 2 days off in a row. Children should get at least 60 minutes of moderate physical activity on most days of the week. You can walk, bike, dance, swim, or garden for aerobic exercise. Do not sit for more than 30 minutes at a time.
- Fiber-Rich Foods: Eat more high-fiber foods. Choose foods that are good sources of fiber, such as fruits, vegetables, and whole grains. Cereals that contain 5 or more grams of fiber per serving are good sources of fiber.
- Active Participation: You have the right to help plan your care. Discuss treatment options with your healthcare provider to decide what care you want to receive. You always have the right to refuse treatment.
Example of a Daily Meal Plan
Here’s what you might eat in a single day on the diabetes exchange diet.
Breakfast
Pick Whole Over Refined Grains at Breakfast
A typical breakfast might include:
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- A poached egg
- A serving of fresh fruit, such as half a grapefruit
- Two slices of toast with 1 tsp spread and 8-oz glass of skim milk
Another option could be:
- 1 1/2 cup whole-grain, unsweetened breakfast cereal
- 1/2 cup sliced fruit
- 1/4 cup unsalted nuts, like almonds
- 1 cup skim milk
Lunch
Go for Lean Protein at Lunch
Lunch could be:
- A whole-wheat turkey sandwich
- 3/4 oz of pretzels
- A side salad topped with fat-free dressing
- 3/4 cup sliced fruit
Use low-sodium, skinless turkey or chicken breast, or drained canned light tuna instead of fattier cuts of red meat whenever possible.
The Ecuadorian Food Exchange List: A Case Study
In Ecuador, the development of a national food exchange list was crucial due to the lack of reliable information on the nutrient composition of many local food items and the scarcity of data concerning serving sizes as standard kitchen measurements. A list of Ecuadorian food exchanges was constructed by going through the following phases: (1) Selection of household measurements; (2) Selection of tables and databases of the nutritional composition of food items; (3) Definition of food groups and quantities; (4) Determination of the average energy and macronutrient values of each group; and (5) Photographic record.
Selection of Household Measurements
Given that one of the objectives of the exchange lists is the management of quantities in grams through the use of household measurements, for this study, those measurements were selected by considering two stages, as follows. (i) The most frequently sold household measurements in key retail centers, such as hypermarkets and specialized stores, were recorded and a preliminary list was set out. At this stage, a list of the household measurements most frequently sold by the retail center was requested. Based on that, the 10 most frequently sold measurements in each category were chosen and a preliminary photographic record was made. (ii) The preliminary list was evaluated by a group of experts in food intake recording. At this stage, nutritionists and experts in dietary intake from different regions of the country (the coastal, Highland, and Amazon regions) were contacted and they voluntarily agreed to evaluate the preliminary list with the respective images. Finally, the experts’ answers were contrasted, the criteria were unified with the research group, and the most commonly used household measurements in the country were defined. The process of selecting the household measurements most frequently used by Ecuadorian homes made it possible to define the most commonly used sizes.
Selection of Food Items and Nutrients
The list of food items and nutrients was selected according to the food and culinary culture and eating habits of the Ecuadorian diet, based on the food consumption database from the National Health and Nutrition Survey (ENSANUT 2011-2013). The nutritional information of food items was obtained using the food composition tables (FCT) from countries in the region. Data were obtained mainly from eight information sources, where the Central American food composition table was the main reference source. For those food items not found in this table, other sources were used: FoodData Central in the United States; Peruvian food composition tables; Colombian food composition table, 1st and 2nd ed. Once the nutritional composition of each food was established, an analysis of variability was performed to detect the variation between individuals according to the following nutrients: energy, carbohydrates, proteins, fats, iron, calcium, zinc, and vitamins A and C. Therefore, the preliminary list included food items that are frequently consumed and those that provide critical nutrients for the Ecuadorian population.
Definition of Food Groups and Quantities
The exchange list was constructed by considering the food groups recommended by FAO and WHO in the Codex Alimentarius. In all cases, for each food item, the amount in grams was evaluated according to Ecuadorian dietary and culinary practices and, when necessary, we followed the recommendations of the national guidelines INEN 1334-2 that regulates the portion size for packaged food products. For each food group, food items whose amounts met the statistical criteria for macronutrients were included. The values established by Wheeler et al. were used, taking as a reference the representative macronutrient for each food group, where a standard deviation of ±2SD was considered, i.e., ±5 g for carbohydrates, ±2 g for total fat, and ± 3 g for protein, as appropriate. Furthermore, once the criteria for macronutrients were met, the energy and caloric value of each food item was calculated by multiplying the carbohydrate (4 kcal/g), fat (9 kcal/g), and protein (4 kcal/g) content by their respective Atwater factors. If the SD value was outside these limits, the food item was removed from the group and relocated to a more appropriate group. Once the SD was adjusted, the coefficient of variation (CV) was estimated to be less than 30%. In addition, for those groups in which the CV was high, the Z value for each food was calculated in order to eliminate foods with high variation. The Z value was considered to be ±2. Once the quantities were defined in the database, raw and cooked weights were recorded for all food items in an experimental kitchen, using an electronic scale (METTLER TOLEDO, 0.5-3,100 g; ±0.01 g), depending on the most common form of consumption. A triplicate record was applied to each measurement [(weight (g), length (cm), width (cm), and height (cm)] to reduce measurement variability.
Determination of Average Energy and Macronutrient Values
The macronutrient values for each exchange group correspond to the average in grams of the food list in each group and are presented as whole numbers (values less than 0.5 were rounded down and values greater than 0.5 were rounded up). Finally, in the case of the energy of each exchange group, the values correspond to the average amount in kilocalories (kcal) and were rounded to the nearest ten; for example, for the low-carbohydrate fruit group, an average intake of 47 kcal was recorded, which was rounded up to 50 kcal in order to present easy-to-remember numbers for the practitioner.
Photographic Record
For this, we worked with a professional camera (Canon EOS 7D) and a lighting scheme for products, which consisted of two softbox lights with flash triggers (Hensel Integra 500), a zenithal side light as the main light and a semi-zenithal side light as a secondary light, plus a silver reflective bouncer to help reduce shadows and maintain the volume. An ISO of 100 was used, so as not to produce marked grain detail, along with a 70 mm medium telephoto lens (Zeiss Canon Mount) so as not to produce any distortion, and an average camera angulation of 50 degrees. In this research, the aim of the photography was not to beautify the food, as happens in the commercial field. On the contrary, what was sought was for the food to look natural and be perceived as if the consumer was seeing it in order to consume it. This concept was the driving force for the inclination of the camera and the technical decisions of the photography. It was necessary to change the framing and settings on several occasions due to the type of food and household measurement that contained it, because it is different to, for instance, photograph a food item in a cup than one in a spoon. A total of 2,600 photographs were recorded since several photographic proofs were needed for each food item, given that between one food item and another the parameters of lighting or framing were adjusted when necessary. The selection and editing process focused on standardizing and/or correcting minor aspects without altering the proportions, colors, or shapes of the images. Finally, 586 photographs were obtained, corresponding to 404 food items, which constitute the photographic record of the food exchange list.
Resulting Food Groups
For the definition of food quantities, statistical criteria were applied according to a standard deviation of ±2SD; thus, for carbohydrates: ±5 g, total fat: ±2 g, and protein: ±3 g. The list of food exchanges is presented with eight general groups according to the predominant nutrient (carbohydrates, proteins, or fats), and, where necessary, subgroups are included according to the second predominant nutrient. The list includes 404 food items with their photographic record, represented by their net weights and corresponding household measurement. The list of food groups was established according to the predominant macronutrient (carbohydrates, proteins, or total fats). For example, in the group of legumes, proteins were considered the most representative nutrient, while carbohydrates were the most representative for the group of cereals, tubers, and plantains. Finally, 8 general food groups were derived, including each food item’s net weight that met statistical requirements and the equivalent in household measurement. Moreover, to differentiate the high, medium, or low content of the predominant macronutrient, certain food groups were also organized into subgroups. For example, in the vegetable group they were classified according to their carbohydrate content into (a) low in carbohydrates (CHO = 5 g) and (b) freely consumable (CHO = 3 g). When necessary, a predominant secondary nutrient was considered in order to organize the subgroups, as in the case of the cereals, tubers, and plantains group where the main macronutrient was carbohydrates and the secondary nutrient was fats, resulting in subgroups with (a) medium or (b) low total fat content; this same criterion was established in the dairy group.
Significance of the Ecuadorian Food Exchange List
This is the first list of Ecuadorian food exchanges based on statistical criteria. It represents a novel tool for public health professionals as well as researchers. Resulting healthier eating plans may improve daily dietetic practice, facilitate better clinical trial designs and help establish guidelines according to Ecuador’s cultural and dietary patterns. The described methodology can further be used to develop other food exchanges lists for patients with specific nutritional requirements.
Benefits of Using the Exchange System Diet
Dietary intervention is an essential part of the prevention and treatment of metabolic pathologies, such as chronic non-communicable diseases like diabetes, obesity, or metabolic syndrome, which are becoming more and more widespread, reaching epidemic levels in various countries. This situation requires an adequate management of the food portions from each food group that make up a healthy eating pattern. Thus, a food exchange list providing food options that are achievable and sustainable within the culture, preferences, and capabilities of each country’s population enables dietary planning because it includes a list of foods with similar contributions of energy and macronutrients.
The food exchange system has been designed to help convert evidence-based nutrition recommendations into food choices according to Ecuador’s dietary patterns. For the development of the food exchange list, it was first necessary to establish the most commonly used household measurements in the population since these tools allow the patient to manage their diet in an autonomous way. For this reason, the process of defining said measurements was based on the identification of the measurements that are most commonly sold in large-scale vending centers on the one hand, and on the other hand, based on the recommendations of the team of experts in food intake in the different regions of the country.
- Improved Blood Sugar Control: The exchange system is particularly beneficial for individuals with diabetes as it helps them manage their carbohydrate intake and maintain stable blood sugar levels. A meal plan with the right amount of carbohydrates is especially important. Your blood sugar rises after you eat carbohydrates. Too many carbohydrates in 1 meal or snack can raise your blood sugar level too much. Simply put, diabetic exchanges can help you see how foods fit into your daily meal plan. They make it easier to add variety to your diet while ensuring your blood sugar stays under control.
- Weight Management: By controlling portion sizes and macronutrient ratios, the exchange system can aid in weight loss or maintenance.
- Increased Dietary Variety: The exchange system encourages individuals to explore different food options within each category, promoting a more balanced and enjoyable diet. Exchange foods are listed together because they are nutritionally comparable. That is, each measured serving of food on that list has about the same amount of carbohydrate, protein, fat and calories as do the other foods on that list. Therefore, any of those foods can be “exchanged” or traded for another food on the same list. For example, a slice of bread for breakfast could be traded for 1/2 cup of cooked cereal if you preferred.
- Enhanced Nutritional Awareness: The exchange system helps individuals become more aware of the nutritional content of different foods and how they impact their health.