Diabetes mellitus (DM) is an endocrine disorder characterized by the body's inability to synthesize or respond to a hormone known as insulin. In a healthy person, insulin is produced by the pancreas and is responsible for lowering blood sugar levels by promoting the cellular uptake of glucose. There are three main types of DM; type one DM (T1DM), type two DM (T2DM), and gestational diabetes. Despite the underlying physiological differences between the three types, they all share a common factor. Namely, all individuals diagnosed with diabetes must monitor their diet closely and control their intake of carbohydrates in order to prevent dangerous spikes or crashes in blood glucose (sugar) levels. In 1950, the American Dietetic Association, the American Diabetes Association and the U.S. Public Health Service designed the Diabetes Food Exchange System to assist diabetics in monitoring their carbohydrate intake. This system divides foods into five groups based on their nutrient content and caloric amounts. Those groups are carbohydrates, fats, meat and meat substitutes, fast food and combination foods.
Counting Carbohydrates Using the Diabetes Exchange System
Carbohydrates act as our body's main source of energy, with each gram providing four calories. They are predominantly found in fruits, vegetables and grains such as pasta, rice, oats, and bread. The Recommended Daily Allowance (RDA) for carbohydrates is 130 g for males and females aged 19 to 50 years. According to the American Diabetes Association, it is advisable to limit the amount of carbohydrates ingested to 45 to 60 g at one meal in order to maintain steady blood glucose levels. To count your carbohydrates, start out by obtaining the Diabetes Food Exchange lists for carbohydrates. These are available online or in any introductory nutrition textbook. It is important to note that the carbohydrate group is further divided into the following subgroups: starch, fruit, milk, vegetables and other.
Starch
The starch subgroup includes foods, such as bread, cereals, crackers and dried beans. Each serving of starch provides 15 g of carbohydrates. For instance, one slice of bread, 1/2 cup of cooked pasta, two rice cakes or 1/2 cup lentils count as one serving of starch and contain 15 g of carbohydrates.
Fruits
Fruits provide a wealth of essential vitamins, minerals and fiber. Like starch, a serving of fruit contains 15 g of carbohydrates. For example, one small apple, three dates or 1 cup of strawberries counts as a fruit serving and provides 15 g of carbohydrates. As a rule of thumb, a serving of fruit is one small fresh fruit, 1/2 cup of fruit juice or 1/4 cup of dried fruit.
Vegetables
Vegetables are rich sources of fiber, vitamins, minerals and protective antioxidants. According to the exchange list, each serving of vegetables provides merely 5 g of carbohydrates. In general, 1 cup of raw veggies or 1/2 cup of cooked veggies counts as one vegetable serving and contains 5 g of carbohydrates. It is important to note that some vegetables, such as peas, potatoes, corn and winter squash contain large amounts of starch and are thus called starchy vegetables. Those vegetables belong to the starch group and provide 15 g of carbohydrates per serving.
Milk
Milk is a rich source of protein and calcium, essential nutrients for healthy growth and development. According to the exchange system, each serving from the milk group contains 12 g of carbohydrates. A serving of milk is 3/4 cup of plain yogurt or 1 cup skim, low-fat or whole milk. Other dairy products, such as cheese, do not contain considerable amounts of carbohydrates and are therefore excluded from the carbohydrate exchange list.
Other Carbohydrates
The diabetes exchange system includes an additional carbohydrate subgroup entitled "other carbohydrates." This subgroup includes food items, such as brownies, cookies and ice cream. In addition to carbohydrates, these foods usually contain high amounts of dietary fat.
Food Labels
Despite the fact that the exchange system is fairly comprehensive, you might not be able to find certain items on it. In that case, refer to the food label whenever possible to determine the amount of carbohydrates per serving.
References
- American Diabetes Association: Counting carbohydrates
- American Dietetic Association: Exchange lists
- "Nutritional Assessment;" R. D. Lee & D. C. Nieman; 2003
