Eating for two By Debra L. Beck Were your eating habits healthy before pregnancy? If so, great! Keep it up. If not, start now. Adopt a nutritious diet. Aim for a sensible weight gain. And you'll deliver that healthy baby - facing fewer post-pregnancy pounds. Here's a fact: You need more food when you're pregnant to support the growth of your baby and the changes in your own body. Understanding what to eat and, perhaps more importantly, what not to eat are key in ensuring both a healthy baby and a healthy mom. How much weight should I gain? Average weight gain during a healthy pregnancy is between 25 and 35 pounds. How can that be, when your newborn will probably weigh only six to eight pounds? The rest comes from the placenta and your enlarged breasts and uterus, along with extra nutrients and fluids. The numbers will vary: Overweight women should ideally gain a bit less and underweight women a bit more during pregnancy. But more important than your weight gain is the nutrient content of your diet. Make sure to eat plenty of healthy food every day. What should I eat? Empty calories are a no-no during pregnancy. Would you feed your newborn candy bars for breakfast? Then don't feed them to yourself, either. What you eat directly nourishes your baby, and inadequate nutritional intake or too little weight gain in pregnancy can cause a whole slew of problems, including low birth weight, preterm labor and poor fetal growth. Empty calories also fill you up, making it more difficult to to eat enough nutritious food. Try to make all your meals and snacks as nutrient-dense as possible. Too much weight gain, however, can increase the size of your baby so much you may be forced to have a Caesarean section. And you might hate the result later when you've got 25 pounds to lose! The trick is - how do you balance eating more and eating right? Calories, vitamin C, protein, calcium and all the rest. During the first three months, caloric needs increase only a little. Weight gain is minimal, only one or two pounds, and your energy expenditure (to build a baby and move your ever-larger body) hasn't yet increased substantially. So eat well but don't eat much more than usual. During the next six months, however, an additional 300 to 450 calories a day is recommended. You can expect to gain one-half to one pound a week. You'll need protein for cell growth and blood production. But you'll also want to include plenty of fruits and vegetables, whole grains, and milk products. The additional calcium goes to developing your baby's bones as well as protecting your own bone density. If your diet is varied, you should easily get enough nutrients. Drink plenty of water, too, especially if you've been vomiting, since dehydration can cause preterm labor. Increasing fluid intake will also help combat constipation. What shouldn't I eat? Caffeine Caffeine readily crosses the placenta and can affect your baby's heart rate and breathing. High caffeine intake has also been linked to an increased risk of miscarriage. Most experts agree that consuming less than 150 mg of caffeine a day is safe for mom or baby. Try to limit your caffeinated coffee to one cup a day, and choose decaffeinated teas and sodas, fruit juices, or water. Alcohol. If possible, avoid all alcohol during pregnancy. Drinking during pregnancy can cause mental retardation and major birth defects, a condition called fetal alcohol syndrome. Even one drink a day has also been linked to impaired fetal growth and lower scores on the Apgar test that's given right after birth to determine your baby's physical condition. Fish with mercury. Fish is a great source of nutrition, but some types of fish or fish from certain heavily polluted waters contain high levels of mercury, which can interfere with fetal brain and nervous system development. The Environmental Protection Agency advises pregnant women or those who may become pregnant to limit their consumption of freshwater fish to one meal a week (about six ounces of cooked fish). The Food and Drug Administration recommends pregnant women avoid entirely shark, swordfish, king mackerel and tilefish. Should I take supplements? In an ideal world - where expectant moms aren't rushed or tired, suffering from morning sickness, or craving sweets - a well-balanced diet should be sufficient during pregnancy. That said, your family physician may recommend you take a formulated-for-pregnancy multivitamin, particularly if you are malnourished or still smoking. Be careful when taking non-pregnancy formulations - they may have too little of some things, like folic acid, and too much of other things, like vitamin A, which in doses above 10,000 IU (200% of the Recommended Dietary Allowance) can cause birth defects. Alternatively, your doctor might tell you to eat well and just take supplemental iron and folic acid, two nutrients you need more of during pregnancy than a healthy diet can easily provide. If you take dietary supplements, do not use them as an excuse to eat poorly. Think of the supplement as a "just in case" you missed something today. Iron. The amount of blood circulating in your body will increase by about 35% during your nine months of pregnancy, which means you'll have less hemoglobin (the oxygen-carrying molecule) in each pint of blood. Eating iron-rich foods, such as lean red meat, spinach, poultry and dried fruit, will help keep your iron stores full and provide the extra iron needed for a healthy pregnancy. Most physicians agree that taking a daily iron supplement during the last six months of pregnancy is a good idea. Folic acid. Folic acid reduces the risk of having a baby with malformations of the brain and spinal cord (called neural tube defects). The benefits of folic acid in pregnancy are so compelling that flour, breads and other grain products are now fortified with this B vitamin, dramatically increasing dietary intake. But because about half of all pregnancies are unplanned, the U.S. Public Health Service also recommends that all women of childbearing age take 400 mcg of supplemental folic acid. Since the benefits of folic acid only count during the early weeks of pregnancy, it's important to be taking supplements at least a month before you plan to become pregnant. Don't sweat it too much Pregnancy is a time of excitement - and great change. Your body is changing, and your life is changing. Combine this with that occasional craving, and it's likely that you'll slip up now and then and eat a non-optimal diet. Don't sweat it. It's OK to indulge here and there in your favorite snack. You've probably done no harm to your baby. Just try to do better tomorrow. Debra L. Beck is a health and medical writer in Toronto, Canada.  ADDITIONAL INFORMATION American Academy of Family Physicians National Library of Medicine National Women's Health Information Center American Dietetic Association Medem, Inc.