Diabetes Spectrum
Volume 13 Number 3, 2000, Page 149
From Research to Practice/ Medical Nutrition Therapy

Carbohydrate Counting: A Return to Basics

Carbohydrate Counting for People With Type 2 Diabetes

Mary A. Johnson, MS, RD, CDE

Carbohydrate counting is an effective medical nutrition therapy option for adults with type 2 diabetes. This meal planning tool has increased in popularity as a result of research demonstrating the benefits of intensive therapy in individuals with type 1 diabetes.1 It can also lead to improved diabetes control and weight loss in adults with type 2 diabetes. This article describes our experience in teaching carbohydrate counting in a diabetes specialty practice using "carbohydrate homework."

In my full-time practice with an endocrinologist and diabetologist, I see a large population of patients with type 2 diabetes. Nutrition services are provided in one-to-one consultations, and 8–12 patients are seen per day. Our type 2 diabetes population spans the spectrum in terms of educational and socioeconomic level. Whether working or retired, many eat the majority of their meals out or on the run, because their spouse has died, their children are grown, or busy lifestyles don't allow for meals at home. Most have a misconception of the role nutrition plays in their diabetes control.

When patients enter our practice, they often express frustration with their lack of glycemic control, lack of success with weight loss, and continuing problems with weight gain. Patients report frustration that, although they are following a meal plan and their premeal blood glucose levels are close to target, their HbAlc levels are still elevated. It is often at this frustration point that a patient first meets with the dietitian, and the concept of carbohydrate counting is introduced.

Carbohydrate counting with fat- gram counting is an effective way to work on weight loss and to improve the control of diabetes. Carbohydrate is converted to blood glucose almost 100% within approximately 90 minutes after the meal.2 Fat consumption, especially consumption of saturated fat, increases insulin resistance3,4 along with abdominal body fat distribution, which is often associated with type 2 diabetes.5

Patients who understand how different nutrients affect their blood glucose level may be more receptive to strategies designed to improve blood glucose control. Working with patients on an individual basis, I am able to tie diabetes management therapies into their daily experience. My first visit usually includes an overview of diabetes, the role of medications if they are on any, and the role of nutrition and meal planning. One of the most useful tools I have found when working with diabetes patients is the post-meal blood glucose level excursion.

After a discussion of the different nutrients, I have patients do what I call "carbohydrate homework." This involves recording nine meals and blood glucose levels pre- and 90 minutes post-meal. Patients record their blood glucose levels pre- and post-meal for three different breakfasts, three lunches, and three dinners. They also are asked to record the foods they eat, the amount, and if possible (depending on the educational capabilities of the patient), the carbohydrate grams and the fat grams (Table 1).

Table 1. Instructions for "Carbohydrate Homework"

  • Record your blood glucose before and 90 min after each meal for three breakfasts, three lunches, and three dinners.
  • Record what and how much you eat for each of the nine meals.
  • Record the grams of carbohydrate eaten at each meal.
  • Record the grams of fat eaten at each meal.

Often when patients return with their completed homework, they can determine their own diet prescription. When patients see the connection between what they eat and the glycemic response, they are usually impressed. Their pre- and post-meal blood glucose levels guide their carbohydrate and fat choices and portion sizes.

Postprandial blood glucose levels are vital to overall diabetes control. Postprandial blood glucose excursions often cause elevated HbA1c levels.6 Patients may be surprised by the magnitude of these excursions. When evaluating the carbohydrate homework, I average the pre- and post-meal blood glucose levels for each of the three meal categories. I then average the total carbohydrate grams for each of the meals separately and look at the fat consumption. In doing the homework assignments, I suggest:

  • First, looking at the patients' average post-meal blood glucose compared to their average pre-meal blood glucose level and average consumption of carbohydrate for each meal.

  • Asking whether restriction of carbohydrate could result in improved blood glucose control.

  • Being sure to leave patients with a realistic amount of carbohydrate for calorie requirements and nutritional balance.

  • Evaluating each meal separately, because a person's carbohydrate tolerance often varies throughout the day based on activity level and the degree of insulin resistance.

Many individuals still believe that if they avoid sugar they should have no problem controlling their blood glucose levels. The carbohydrate homework shows them that all types of carbohydrate count.

The tools I use to teach carbohydrate-gram counting include food labels and carbohydrate exchange lists. For fat-gram counting, I use the food labels and a handout on the fat content of foods developed by Nutrition Graphics. The food pyramid and the exchange lists facilitate discussion of which foods contain specific nutrients. Food models are also useful tools for demonstrating what size portions contain specific grams of carbohydrate, fat, and protein.

Most patients find that carbohydrate- and fat-gram counting gives them the flexibility they need for family gatherings and special occasions. Today's lifestyle often does not allow the three structured meals that were common not so long ago.

Carbohydrate-gram counting may be easier to use than the traditional exchange lists. However, some patients may be overwhelmed by counting carbohydrate and fat grams. With these patients, I may use carbohydrate exchanges or possibly the food pyramid to count carbohydrate servings. If a patient is still overwhelmed, a structured individualized meal plan outlining what and when to eat is developed. The patient is encouraged to use American Diabetes Association/ American Dietetic Association cookbooks and the Month of Meals books.

Regardless of the meal planning approach selected, the carbohydrate homework is the basis for the meal plans since it provides information about carbohydrate tolerance for both the patient and me to use. This homework also helps patients understand that sometimes food choices may not be the only reason for blood glucose excursions; medication may be required to control blood glucose levels.

If weight loss is a goal, the carbohydrate homework lets patients know precisely how much they are eating, especially if they are able to count the grams of carbohydrate. Serving sizes are often distorted, and many individuals are often surprised to find out just how many carbohydrate and fat grams they are consuming.

Case #1
M.A. is a 73-year-old woman who has had type 2 diabetes since 1972. She is retired, lives with her husband, and has a close-knit family of grown children who live nearby and are often present for family gatherings.

M.A. is taking an oral antidiabetic medication but not insulin, although she has taken insulin in the past. She is 5 ft., weighs 219 lb, and has a body mass index (BMI) of 43, despite working hard on weight loss.

Her HbA1c is 9.3%, and her glucose logbook shows recorded premeal blood glucose levels averaging 140 mg/dl. M.A. has nonproliferative retinopathy and neuropathy affecting her feet and legs such that she can only walk with the assistance of a cane. She does not want to go back on insulin, yet she needs better control of her diabetes and expresses a desire to lose weight.

M.A.'s carbohydrate homework is shown in Table 2.

Table 2. M.A.'s Carbohydrate Homework

  Breakfast Lunch Dinner
  • Average pre-meal blood glucose (mg/dl)
141 163 112
  • Average blood glucose 90 minutes post-meal (mg/dl)
320 194 145
  • Blood glucose excursion (mg/dl)
179 31 33
  • Average carbohydrate g
80 45 60
  • Average fat g
12 25 30

Evaluation of M.A.'s carbohydrate homework

  • Post-breakfast blood glucose excursion is unacceptable. Post- meal blood glucose excursions should be around 30–40 mg/dl. This increase needs to be assessed on an individualized basis based on each patient's blood glucose goals. In some cases, even if the HbA1c is acceptable, the excursion after any one meal may be as high as 80 mg/dl.

  • Total intake of carbohydrate for the day is approximately 185 g or 740 kcals. Total intake of fat is 67 grams or 603 kcals.

Recommendations for M.A.

  • Decrease fat intake to 30–40 g or 270–360 kcals. This would lower the insulin resistance from fat, improve the cardiac profile, and decrease total kcal intake.

  • Limit carbohydrate at breakfast to 30–40 g, at lunch to 45 g, and at dinner to 60 g. This would lower the post-breakfast blood glucose excursion. Lowering the post- breakfast blood glucose excursion should also result in a decrease in pre-lunch and dinner blood glucose levels.

  • The medical nutrition prescription is low in total kcals for weight reduction and maximizes diabetes control. Total intake of carbohydrate would be around 165 g or 660 kcals. Total calorie intake from fat and carbohydrate would be 930–1,020 kcals.

Case # 2
E.V. is a 67-year-old man who is newly diagnosed with type 2 diabetes and is not on any diabetes medications. He has an HbA1c of 10% on diagnosis and a fasting blood glucose level of 200 mg/dl.

E.V. is retired and lives with his wife. He is following a low-fat diet secondary to a history of cardiac problems. He weighs 205 lb, and is 5'7" inches with a BMI of 32. He has not lost weight on the low-fat diet.

E.V.'s carbohydrate homework is shown in Table 3.

Table 3. E.V.'s Carbohydrate Homework

  Breakfast Lunch Dinner
  • Average pre-meal blood glucose (mg/dl)
220 188 185
  • Average blood glucose 90 minutes post-meal (mg/dl)
190 205 180
  • Blood glucose excursion (mg/dl)
-30 17 -5
  • Average carbohydrate g
150 110 109
  • Average fat g
15 12 35

Evaluation of E.V.'s carbohydrate homework

  • E.V.'s total carbohydrate intake is 369 g, or 1,476 kcals.

  • His total fat intake is approximately 60–70 g, or 540–630 kcals.

  • E.V.'s diabetes control is not a nutritional issue. His post-meal blood glucose excursions are acceptable.

  • Weight reduction would be beneficial for a decrease in insulin resistance and hyperlipidemia.

Recommendations for E.V.

  • Begin insulin sensitzer therapy.

  • Follow a low-saturated-fat diet for lipid control.

  • Follow a lower-kcal-diet for weight reduction.

Carbohydrate homework provides professionals the basis for developing a medical nutrion care plan that has the potential to improve blood glucose control. It serves as a mechanism to assess patients' tolerance to carbohydrate and fat and the need for nutritional or pharmacological intervention in the control of type 2 diabetes. Teaching patients with type 2 diabetes carbohydrate counting based on their post-meal glucose excusions can provide increased flexability with food choices and a means for better blood glucose control.

1The DCCT Research Group: The effects of intensive treatment and progression of long-term complications in insulin-treated diabetes mellitus. N Engl J Med 329:977-86, 1993.

2Laine DC, Thomas W, Levitt MD, Bantle JP: Comparison of the predictive capabilities of diabetic exchange lists and glycemic index of foods. Diabetes Care 10:387-94, 1987.

3Boden G, Jadali F: Effects of lipid on basal carbohydrate metabolism in normal men. Diabetes 40:686-92, 1991.

4Mott D, Lilloija S, Bogardus C: Overnutrition induced decrease in insulin action for glucose storage: in vivo and in vitro in man. Metabolism 35:160-65, 1986.

5Bonara E, Del Prato S, Bonadonna R, Gulli G, Solini A, Shank M, Ghiatas A, Lancaster J, Kilcoyne R, Alyassin A, DeFronzo R: Total body fat content and fat topography are associated differently with in vivo glucose metabolism in nonobese and obese nondiabetic women. Diabetes 41:1151-59, 1992.

6Krosnick A: Postprandial hyperglycemia: the clue to intensive diabetes control. Mediguide to Diabetes. Vol. 4, Issue 6. New York, Lawrence DellaCorte Publication, Inc., 1997.

Mary A. Johnson, MS, RD, CDE, is a nutritionist and diabetes educator at Diabetes and Endocrinology Associates in Hamilton, N.J.

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Copyright 2000 American Diabetes Association

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