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What to Do When You're Eating for Two

Susan M. Kleiner, PhD, RD


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I am always happy when a client of mine says she'd like to start eating the right foods before she gets pregnant, rather than waiting until she is already pregnant. Nutritional health is cumulative: How well your body can feed your baby and make it through a pregnancy depends not only on what you eat during your pregnancy, but on how well you have been eating for years (1).

Great Expectations

The months immediately before a pregnancy are especially important for preparing your body for a healthy pregnancy. Once you are pregnant, the wheels of growth begin to turn.

Exercise and diet. Exercise is an excellent way to stay fit and healthy during your pregnancy. Maintain your current level of exercise, but make sure that you are eating the number of calories that you need to support your pregnancy and physical activity. This isn't the time to diet and deplete your body of nutrients.

Folic acid. One of the most critical nutrients in your prepregnancy diet is folic acid, also known as folacin. A low intake of folic acid during the first 3 months of pregnancy has been associated with spinal cord defects in developing fetuses (2). Once you begin thinking about getting pregnant, beef up your folic acid stores by including plenty of dark-green leafy vegetables, dry beans, peanuts, wheat germ, enriched breakfast cereals, and whole grains in your diet. Talk to your doctor about taking folic acid supplements before becoming pregnant.

Building Blocks

During pregnancy, a woman must get all the nutrients she needs to maintain her own body tissues and functions, as well as to grow the placenta and fetus and to breast-feed. About a third of the total weight gained during pregnancy is accounted for by increases in blood volume and total body water. These need to be met with increases in protein and minerals, and electrolytes, which help regulate fluid balance, nerve conduction, and muscle contraction (table 1).

Table 1. Recommended Diet for Pregnancy
Food Groups Nutrients Recommended
Daily Servings
Serving Suggestions
Milk Products Vitamins B12, riboflavin,
and D and A
when fortified
4* 1 c milk or yogurt
2 c cottage cheese
1 1/3 oz. cheese
Breads and
Vitamins folic acid,
niacin, riboflavin,
Iron, magnesium
6-11 1 slice bread
1/2 c cooked cereal,
rice, or pasta
1 oz ready-to-eat
Vegetables Vitamins A, folic
acid, riboflavin
Iron, magnesium
3-5 1/2 c cooked or
chopped raw
1 c leafy raw
Fruits Vitamins C, A
2-4 1-1 1/2 c juice
1/4 melon
1/2 grapefruit
1/4 c dried fruit
Meat and
Vitamins B6,
B12, niacin,
Iron, magnesium,
phosphorus, zinc
3 2-3 oz lean cooked meat
2 eggs
1 c cooked dried
beans or peas
2 Tbsp peanut butter
Fats Vitamins A, E 3-6 1 tsp. margarine
1 tsp vegetable oil
1 Tbsp salad dressing
1 oz. nuts
*For adolescent girls (less than 18 years), 5 servings are recommended.

You'll need an extra 10 g of protein every day. Just 1 cup of skim or low-fat milk and one slice of whole grain bread will meet this requirement. You'll need more of most vitamins, minerals, and electrolytes, but especially calcium, iron, and zinc (3).

Energy requirements increase as your body begins to form new tissues. As your weight increases, it takes more energy to move yourself around. You require an average of 300 extra calories each day to support a healthy pregnancy (3). You can easily meet this by having a cup of milk with a piece of fruit and a bagel.

Early Adjustments

Because you might not know if you are pregnant until the second or third month, once you are trying to conceive it is wise to cut out certain foods that may be harmful to the baby. Many of these foods have their greatest impact on the baby during the first trimester, so the earlier they are eliminated, the better.

Alcohol. Alcohol has been associated with higher rates of miscarriage, low birth weights, and a condition called fetal alcohol syndrome that can include mental retardation and other defects. You should eliminate or severely limit alcohol during this time (4).

Caffeine. Evidence about the effects of caffeine on babies is mixed, but several studies have shown evidence of birth defects (1). To be safe, eliminate or cut down on caffeine.

Sweeteners. During pregnancy it's safest if you sweeten foods and beverages with sugar and other natural sweeteners like honey or molasses, rather than artificial sweeteners. Used moderately, natural sweeteners can add variety to your diet without too many calories (1 teaspoon of white granulated sugar is 15 calories). Make sure, though, that sugars don't take the place of more nutrient-dense calories in your diet.

Foods to Forgo

One concern for pregnant women is food contamination. Contaminants can exist naturally in foods or come from pollution. Even a little bit of contamination can affect the health of your baby. To avoid lead contamination, fruit juice and acidic foods should be stored in glass or plastic instead of leaded crystal or ceramic containers. Test the lead content of tap water from older homes with lead pipes and faucets.

Large fish can be contaminated with mercury. Play it safe by avoiding swordfish, shark, and marlin, and limiting your tuna intake to 1/2 pound per week. Fresh fish also can be contaminated with pesticides and polychlorinated biphenyls (PCBs), which are toxins. Fish from inland waterways (such as the Great Lakes) may be contaminated with PCBs. Wild (not farmed) freshwater carp, catfish, lake trout, whitefish, bluefish, mackerel, and striped bass are the most likely to contain high PCB levels (5). Because these toxins usually accumulate in fat, stick with low-fat fish and trim the fat off the fish you eat.

Food poisoning by bacterial contamination can also be harmful. If you are traveling in foreign countries, play it safe and don't eat food that is uncooked or from street vendors (this includes fruits and vegetables.) Use only boiled or bottled water, including the water used for ice cubes. Soft cheeses like Brie and Camembert can be contaminated with a bacteria called listeria. Skip these during your pregnancy.

Certain foods that you may normally eat in their raw form should be avoided while you are pregnant because they may contain parasites. The list includes unpasteurized milk, and raw or undercooked shellfish, fish (sushi), eggs, poultry, or meat. Steer clear of foods that contain raw eggs, such as homemade eggnog, ice cream, Caesar salad dressing, raw cookie dough, and pancake batter (5).

Healthy Gains

Part of having a healthy pregnancy means gaining some fat weight. As your body prepares for breast-feeding, it lays down fat to store the extra energy that will be used to make milk. One of the benefits of nursing is that, as long as your weight gain during pregnancy was normal, and if you diet and exercise after giving birth, nursing can help you lose fat.

Many women exercise to maintain their weight and stay in shape. After working so hard to get your body fit and toned, it may take some psychological adjustment to accept a pregnant body. But within that 9 short months you have the critical job of giving your baby all the energy and nutrients that it needs to grow healthy and strong. The average weight gain during pregnancy is 26 to 32 pounds. Celebrate those gains and think of it this way: You've built a healthy body for yourself—and now it's your baby's turn.


  1. The Surgeon General's Report on Nutrition and Health: Publication Health Service (PHS) publication no. 88-50210. Washington, DC, US Dept of Health and Human Services, 1988
  2. Prevention of neural tube defects: results of the Medical Research Council Vitamin Study, MRC Vitamin Study Research Group. Lancet 1991;338(8760): 131-137
  3. Food and Nutrition Board, National Research Council. Recommended Dietary Allowances, ed 10. Washington, DC, National Academy Press, 1989
  4. Mills JL, Graubard BI, Harley EE, et al: Maternal alcohol consumption and birth weight: how much drinking during pregnancy is safe? JAMA 1984;252 (14):1875-1879
  5. Jacobson MF, Lefferts LY, Garland AW: Safe Food: Eating Wisely in a Risky World. Los Angeles, Center for Science in the Public Interest and Living Planet Press, 1991

Remember: You, your physician, and your nutritionist need to work together to discuss nutrition concerns. The above information is not intended as a substitute for appropriate medical treatment.

Dr. Kleiner is a private nutrition consultant to athletes in the Seattle area. She is a member of the American College of Sports Medicine and of the American Dietetic Association and its practice group, Sports and Cardiovascular Nutritionists (SCAN), and a fellow of the American College of Nutrition.