Because carbohydrate counting focuses only on the carbohydrates in different foods, it allows for more flexibility than the
exchange system. Carbohydrate counting is particularly useful for people who take insulin shots, since it allows you to balance food intake with insulin. The more carbohydrates you eat, the higher your blood sugar will be, and the more insulin you will need. Of course, always ask your doctor before adjusting insulin doses on your own.
When you eat carbohydrates, your body turns them into sugar, or glucose. The foods that raise blood sugar the most are those that are high in carbohydrates (eg, starches, milk, fruit, and sweets).
Carbohydrates are often classified as simple or complex. Simple carbohydrates, or “sugars,” include table sugar, honey, high fructose corn syrup, and the sugars found in milk and fruit. Complex carbohydrates, or starches, include whole grains, starchy vegetables, and legumes. Both types affect blood sugar in a similar way, but certain choices in each are healthier than others.
|Healthy Choices||Limit or Avoid|
Simple Carbohydrates (Sugars)
- Low-fat milk and milk products
- Table sugar (eg, cane sugar or sucrose)
- High fructose corn syrup—This is often added to processed foods. Read list of ingredients.
- Foods high in added sugars (eg, sweets, soda)
Complex Carbohydrates (Starches)
- Whole grains
- Starchy vegetables
- Refined starches (eg, white flour, foods made from white flour, and white rice)
One carbohydrate serving is equal to 15 grams of carbohydrate. This is about the amount of carbohydrate in one slice of bread, ¾ cup dry, unsweetened cereal, ½ cup of pasta, one cup of milk, or one small piece of fresh fruit. Since they have similar effects on your blood sugar, they can also be “exchanged.” This is because these foods are generally considered “carbohydrate servings.” For example, you may trade one starch serving for one fruit or milk serving.
The table below gives examples of food that has approximately 15 grams of carbohydrates per serving.
Examples of 15 Grams of Carbohydrates Per Serving
1 slice bread
1/3 cup rice
¾ cup dry, unsweetened cereal
½ cup pasta
1 medium sugar cookie
1 cup milk
4 ounces of juice or soda
1 small piece (or 1 cup) of fresh fruit
½ cup beans
½ cup mashed potatoes
3 cups popcorn
¼ cup granola
1/3 cup hummus
Meats and fats generally contain little or no carbohydrate, while vegetables contain only five grams per serving (one serving equals ½ cup cooked or 1 cup raw vegetables).
There are books that provide more comprehensive carbohydrate count lists. In addition, most packaged foods have labels with the carbohydrate amount.
Most people with diabetes should consume between 45%-65% of their calories as carbohydrates (and the rest from fat and protein). There are four calories in every gram of carbohydrate. So, for example, if you are on a 2,000-calorie diet with 50% of your calories coming from carbohydrates, you can have a total of 16 servings of carbohydrate per day. A registered dietitian can help you determine and calculate the best meal plan for you.
Calculating Carbohydrate Servings
2,000 calorie diet
50% of calories from carbohydrates = 1,000 calories
1,000 calories divided by 4 calories per gram of carbohydrate = 250 grams
250 grams divided by 15 grams carbohydrate per serving = 16.66 servings
How you distribute these servings will affect your blood sugar. So, try to be consistent from day to day, but adjust as needed to keep blood sugars within your target range.
The bottom line is you should space out your carbohydrate servings into at least three meals per day. In addition, the more fiber the carbohydrates contain, the better the effect on your blood sugar. The table below shows examples of different ways that these 16 carbohydrates could be distributed:
When following the carbohydrate counting diet, foods consisting mainly of protein or fat (eg, meat and oils) should be eaten in moderation even though they are not technically counted. If they are eaten in excess, you may exceed your target calorie level and gain weight. Foods that are high in saturated fat, trans fat, and cholesterol should also be limited to decrease your risk of developing cardiovascular disease.
Fiber is a carbohydrate. But, because the body cannot break it down, it does not affect blood sugar. If you eat many high-fiber foods, you may want to talk to a dietitian about label reading to learn how to subtract the “dietary fiber” grams from the “total carbohydrate” grams. This subtraction gives you a more accurate estimate of the carbohydrates that will affect your blood sugar.