Major Food Components
Compared to fats and protein, carbohydrates have the greatest impact on blood sugar (glucose). Except for dietary fiber, which is not digestible, carbohydrates are eventually broken down by the body into glucose. Carbohydrate types are either complex (as in starches) or simple (as in fruits and sugars).
One gram of carbohydrates provides 4 calories. The current general recommendation is that carbohydrates should provide between 45 - 65% of the daily caloric intake. Carbohydrate intake should not fall below 130 grams/day.
Complex carbohydrates are broken down more slowly by the body than simple carbohydrates. They are more likely to provide other nutritional components and fiber.
- Vegetables, fruits, whole grains, and beans are good sources of carbohydrates. Whole grain foods provide more nutritional value than pasta, white bread, and white potatoes. Brown rice is a better choice than white rice.
- Patients should try to consume a minimum of 20 - 38 grams of fiber daily (or even up to 50 grams/day), from vegetables, fruits, whole grain products such as cereals and breads, and nuts and seeds.
- Whole grains specifically are extremely important for people with diabetes or those who are at risk for it. [For specific benefits, see: "Whole Grains, Nuts, and Fiber-Rich Foods," below.]
Simple carbohydrates, or sugars (either as sucrose or fructose), adds calories, increases blood glucose levels quickly, and provides little or no other nutrients.
- Sucrose (table sugar) is the source of most dietary sugar, found in sugar cane, honey, and corn syrup.
- Fructose the sugar found in fruits, may produce a slower increase in blood sugar than sucrose. Dark-colored fruits are rich in important vitamins and other nutrients. Other fruits, such as apples and grapes also have important beneficial food chemicals.
- People with diabetes should avoid products listing more than 5 grams of sugar per serving, and some doctors recommend limiting fruit intake. If specific amounts are not listed, patients should avoid products with either sucrose or fructose listed as one of the first four ingredients on the label. [See: "Fat Substitutes and Artificial Sweeteners," below.]
The Carbohydrate Counting System. Some people plan their carbohydrate intake using a system called carbohydrate counting. It is based on two premises:
- All carbohydrates (either from sugars or starches) will raise blood sugar to a similar degree, although the rate at which blood sugar rises depends on the type of carbohydrate. In general, 1 gram of carbohydrates raises blood sugar by 3 points in people who weigh 200 pounds, 4 points for people who weigh 150 pounds, and 5 points for 100 pounds.
- Carbohydrates have the greatest impact on blood sugar. Fats and protein play only minor roles.
In other words, the amount of carbohydrates eaten (rather than fats or proteins) will determine how high blood sugar levels will rise. There are two options for counting carbohydrates: advanced and simple. Both rely on collaboration with a doctor, dietitian, or both. Once the patient learns how to count carbohydrates and adjust insulin doses to their meals, many find it more flexible, more accurate in predicting blood sugar increases, and easier to plan meals than other systems.
The basic goal is to balance insulin with the amount of carbohydrates eaten in order to control blood glucose levels after a meal. The steps to the plan are as follows:
The patient must first carefully record a number of factors that are used to determine the specific requirements for a meal plan based on carbohydrate grams:
- Multiple blood glucose readings (taken several times a day)
- The time of meals
- Amount in grams of all the carbohydrates eaten
- Time, type, and duration of exercise
- The time, type, and dose of insulin or oral medications
- Other relevant factors, such as menstruation, illness, and stress
The patient works with the dietitian for two or three 45 - 90 minute sessions to plan how many grams of carbohydrates are needed. There are three carbohydrate groups:
Review Date: 05/05/2011
Reviewed By: Harvey Simon, MD, Editor-in-Chief, Associate Professor of Medicine, Harvard Medical School; Physician, Massachusetts General Hospital. Also reviewed by David Zieve, MD, MHA, Medical Director, A.D.A.M., Inc.