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Nutrition Management Of Gestational Diabetes Mellitus
By - Dr. Dharini Krishnan
Consultant dietitian, Chennai. Former President, Indian Dietetic Association

Gestational Diabetes Mellitus (GDM) has been defined as "glucose tolerance of variable severity with its onset or fist recognition during pregnancy". Pregestational diabetes is the term used: if a lady who is known to have diabetes and is under treatment conceives, she is said to have a pregestational diabetes. Since hyperglycemia is present throughout the pregnancy and not just in the second half as occurs in GDM, this group of patients are more prone for certain complications like congenital malformations of the fetus, worsening of the diabetic complications in the mother, etc.

The goals of Medical Nutrition Therapy (MNT) to achieve normoglycemia, prevent ketosis, provide adequate weight gain and contribute to fetal well being. The calorie allotment according to body weight is:

Current Weight (As % of Ideal Body Weight) Category Recommended Daily Calorie Intake (kcal/kg) Recommended total weight gain in all 3 trimesters of pregnancy (kg)
< 80-90 Underweight 36- to 40 12.5 to 18.0
0 to 120 Ideal 30 11.5 to 16.0
120 to 150 Overweight 24 7.0 to 11.5

All women with GDM should receive nutritional counselling. The meal pattern should provide adequate calories and nutrients to meet the needs of pregnancy. The expected weight gain during pregnancy is 300 to 400 gm/week and a total weight gain of 10 to 12 kg by term. The Meal plan should focus on maintaining euglycemia and to provide sufficient calories to sustain adequate nutrition for the mother and fetus and to avoid excess weight gain and post prandial hyperglycemia. Obesity correction is not an ideal thing to attempt during pregnancy.

Breakfast calories can be split into two meals, one at 8 am another at 10 am to prevent the undue peak in plasma glucose levels. Peaking of plasma glucose is high with breakfast.

Carbohydrates should be restricted to 40 to 45 per cent of the total calories, the remaining divided between protein and fat. The calorie should be distributed into three meals and three snacks. A bedtime snack is insisted to prevent ketosis in fasting.

The best way for a GDM patient's diet is by eating a variety of healthy foods.

In general, the diet should be:

  • Provide controlled levels of carbohydrates through foods. The carbohydrate should be provided by millets such as ragi, bajra, saamai and varagu. Use whole wheat and red rice in the diet. Restrict foods made from maida and sugar such as pastries, rusks, bun and bread. Whole wheat bread may not be hundred per cent wheat and hence one has to read the labels.
  • Lower in foods that have a lot of sugar, such as bottled drinks, fruit juices, and pastries.
  • The GDM patient should never skip a meal.
  • There are many products like ice creams and cake mixes which are sold as sugar free. It may contain sugar alcohols which are not good to eat. Some sugar free products contain more than eighty per cent of carbohydrates and saturated fat. So learn to read the labels and know what is safe to eat.
  • Eat 3 - 5 servings a day: one serving equals 1 cup leafy, green vegetables; 1 cup cooked or chopped raw leafy vegetables; 3/4 cup vegetable juice; or 1/2 cup of chopped vegeta bles, cooked or raw. Use a large variety of vegetables such as gourds, beans variety and green leafy vegetables. The starchy vegetables can be exchanged for the cereal portion once in a way.
  • Choose fresh or frozen vegetables without added sauces, fats, or salt. You should opt for more colours in the vegetables. orange, green and red. Carrots, tomato and green leafy vegetables should be used regularly and in sufficient quantities.
  • Choose whole fruits more often than juices. They have more fiber. Citrus fruits, such as oranges, guava, papaya, pomegranate, watermelon, pears can be used. Apple and banana should be in half cup portion sizes. Jack fruits and mangoes should be restricted and quantities also restricted as they can spike the glucose levels.
  • Milk or curd can constitute about 400 to 500 ml of the diet. It helps a vegetarian include high biological value proteins and gives a good source of calcium.
  • Two to three servings of dhal or sambhar or sundal (whole pulses boiled) or substituted with fish or chicken or egg. Use less oil in cooking of non vegetarian foods or while preparing channa or rajma.
  • Traditional oils are good for health. Three fourth of the amount provided can be from traditional oil and quarter can be from sunflower oil. Those using olive oil also have to fit the total oil consumption to half a litre a month.
  • Starchy foods eventually turn into glucose so it's important not to be excessive. However, starch should be included as it is usually tolerated the best.
  • Don't add sugar, honey or syrup to your foods.

Be sure to record all of the foods and the amount that you eat each day, which will help you monitor your carbohydrate intake. Also, use measuring cups for accuracy when possible.

As not all women with GDM respond the same to carbohydrate loads, try a modest carbohydrate level (not <50% of calories) distributed among 3 meals and 3 snacks first. A percentage of women will not keep blood glucose levels within target range on this amount. It may help to decrease to 45% of calories.

Use a daily exercise program as an adjunct to treatment if possible to help attain maternal euglycemia. If blood glucose cannot be kept within target range, insulin may be added.

References:-

  1. American Diabetes Association. Standards of medical care in diabetes -- 2012. Diabetes Care. Jan;25 Suppl 1:S11-63.
  2. Cunningham FG, Leveno KJ, Bloom SL, et al. Diabetes. In: Cunningham FG, Leveno KL, Bloom SL, et al, eds.Williams Obstetrics. 23rd ed. New York, NY: McGraw-Hill; 2010:chap 52.
  3. Thomas N et al. A practical Guide to Diabetes Mellitus. 6th Edition, 2012.
  4. Tripathy BB, Chadalia HB et al. RSSDI Textbook for Diabetes Mellitus, 2nd Edition, 2012.