Volume 13 Number 3, 2000, Page 149
Carbohydrate Counting: A Return to Basics
Carbohydrate Counting for Pregnant Women
Diane Reader, RD, LD, CDE
At no other time is blood glucose control so crucial as when a woman with diabetes is pregnant or planning to get pregnant. It is an exciting time but also a challenging one. Counting food, testing blood glucose levels, and adjusting insulin doses becomes a way of life. Carbohydrate counting can be a useful way to intensify control for women with type 1 diabetes, and it can be an easy way to learn food management for women with gestational diabetes mellitus (GDM).
Case #1: Gestational Diabetes
Kim is like many other women who are diagnosed with GDM and referred to our adult endocrinology clinic, which is part of a large multi-specialty practice. With six endocrinologists, two diabetes nurse educators, and two diabetes nutrition specialists, we manage at any given time 3050 pregnant women with either GDM or pre-existing diabetes.
After we receive a telephone referral, our protocol is to see these women within 48 hours. These are high-priority patients, and glucose control needs to be established as soon as possible.
There are two reasons for our urgency to see these women. Women with GDM are often frightened and worried about what to eat and whether they will have to go on insulin. The main reason, however, is that GDM is a usually a short-lived disease lasting about 12 weeks, from about 28 weeks of gestation to delivery. To prevent macrosomia, euglycemia must be achieved quickly; waiting a week or two for an open appointment is not acceptable.
The first clinic visit lasts about 2 1/2 hours. The first hour is with the nurse educator, who teaches the patient about GDM and how to monitor blood glucose levels. In the next hour, the diabetes nutrition specialist takes a diet history and determines and teaches a food plan. The physician wraps up the appointment with a focus on answering questions, evaluating the need for insulin, and determining the follow-up schedule.
For many years, we have taught the food plan using carbohydrate choices per meal and snack instead of using a calorie-based exchange diet. We teach patients with GDM how to read a food label. Women quickly understand which foods contain carbohydrate. We teach them to count 15 g of carbohydrate as one "choice" and how to include small portions of foods containing sugar, such as a cookie or 1/2 cup of ice cream. An individualized food plan is developed for each patient based on her schedule. In general, food plans include: a) a small breakfast containing 2 carbohydrate choices, b) two moderate-sized meals containing 3 or 4 carbohydrate choices, and c) 2, 3, or 4 snacks containing less than 3 carbohydrate choices each.
Patients are instructed to keep daily food records, test urine for ketones each morning, and record four blood glucose tests each day: before breakfast and 1 hour after breakfast, lunch, and dinner. At the first follow-up visit, which is scheduled in 12 weeks, these records are reviewed and patients' weight is checked. The outcomes we strive for include fasting and post-meal blood glucose levels within target range, negative urine ketones, appropriate weight changes, and appropriate food intake. Another follow-up visit is usually scheduled to assess outcomes. The need for further follow-up is determined based on the number of weeks until delivery and how well the woman is doing.
The dietitian's role during follow-up visits is to review patients' food records to determine the need for more education, meal plan revisions, or insulin. Most women who are overwhelmed at the first session benefit from a review of carbohydrate counting and label reading. In an effort to achieve the recommended blood glucose levels, some women eat less than the meal plan and need assurance that they can eat more carbohydrate and calories. Another common problem is not eating the recommended number of snacks, which can lead to under eating. Many women have questions about how to count restaurant meals, fast foods, and combination dishes. For some women, even strict adherence to an appropriate meal plan results in blood glucose values outside the target range, which indicates the probable need for insulin. Women with GDM are usually motivated because they desire a healthy baby and work very hard to do whatever it takes to achieve that.
Carbohydrate counting is a useful and beneficial method because it is quickly learned. However, just counting carbohydrates does not provide a specific framework for calories, protein, fat, or the elements of a nutritionally balanced diet that are crucial during pregnancy. When using carbohydrate counting for GDM management, it is recommended to indicate how many carbohydrate choices should come from milk, from fruit, and from starch. For example, instead of recommending 4 carbohydrate choices per meal, dietitians need to direct these women to eat 2 choices from the starch group, 1 from the fruit group, and 1 from the milk group. Additional servings of protein (and fat) may be needed to keep the caloric intake adequate.
Carbohydrate counting is based on the assumption that a "carbohydrate is a carbohydrate is a carbohydrate." But anyone that has worked in the management of blood glucose levels with a woman with GDM knows that this rule of thumb does not always apply. Unfortunately, very little research has been done to provide scientifically based guidelines. Most clinicians have discovered that certain foods, particularly highly processed foods, produce higher postprandial readings. Therefore, these foods are not initially recommended in a food plan.
The glycemic index is another tool to consider in the management of GDM. However, additional research studies need to be done. One drawback to the use of the glycemic index is the potential for avoiding nutritious foods, such as baked potatoes, parsnips, and cherries, in an effort to achieve glucose control. For a condition such as GDM, which lasts only 23 months, the glycemic index may be too cumbersome to implement.
The Diabetes Care and Education and the Women and Reproductive Health practice groups of the American Dietetic Association have developed Nutrition Practice Guidelines for Gestational Diabetes Mellitus. These guidelines will be published this year. The practice guideline committee found that a variety of methods, including carbohydrate counting, are used successfully to teach meal planning for women with GDM. As long as the clinical outcomes are achieved, there is no right or wrong way to teach meal planning.
Case #2: Pregnancy in Type 1 or Type 2 Diabetes
In our practice, we prefer using both carbohydrate counting and the exchange system for pregnant women. The exchange system helps guide women to consume appropriate calories, protein, and nutrients to achieve excellent nutrition and appropriate weight gain. Carbohydrate counting helps achieve insulin intensification and excellent glucose control.
When we begin to work with a patient to intensify her blood glucose control, we start with a consistent carbohydrate meal plan (using either grams or choices). The patient is asked to follow that food plan and to check blood glucose values before and 2 hours after each meal. With frequent phone contact or office visits, a baseline insulin regimen is determined. At that point, a carbohydrate-to-insulin ratio can be determined as well as an algorithm for adjusting insulin to account for changes in carbohydrate intake.
In the nonpregnant state, carbohydrate-to-insulin ratios give people with diabetes flexibility. Using carbohydrate-to-insulin ratios during pregnancy is more challenging because insulin requirements change so often. In the first trimester, the body is more sensitive to insulin, and insulin requirements drop. Also nausea and vomiting frequently occur. Understanding how to adjust insulin for changes in food intake is very helpful to getting through this rocky trimester. During the second half of the pregnancy, insulin resistance causes an increase in the insulin requirement so that weekly insulin adjustments are made. At this point in the pregnancy, we prefer that women eat a consistent carbohydrate diet and avoid large variations in intake.
Diane Reader, RD, LD, CDE, is Manager of Health Professional Programs at the International Diabetes Center in Minneapolis, Minn.
Copyright © 2000 American Diabetes Association
Last updated: 9/00