A guide on what you should (and shouldn't!) eat for a healthy pregnancy. 

pregnant woman cooking
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How much should you be eating?

Eating properly during pregnancy is one of the most beneficial things you can do for your baby -- and for yourself. You may be ravenous, but you really need only an additional 300 calories a day to gain the 25 to 35 pounds a normal-weight woman should throughout pregnancy, according to the American College of Obstetricians and Gynecologists (ACOG).

"That doesn't add up to much -- approximately three cups of skim milk," says Bridget Swinney, R.D., author of Eating Expectantly: A Practical and Tasty Approach to Prenatal Nutrition.

It's okay to give in to the occasional craving for Twinkies or ice cream, as long as you make smart choices about the nutrients you consume overall. Follow our eat-right guidelines to stay healthy yourself, and to help your unborn baby grow.

Concentrate on carbohydrates.

Bread, rice, pasta, cereals, fruits, and vegetables are your body's primary sources of fuel and should provide more than half of your daily calories. Try to have at least nine servings of whole-grain foods, four servings of vegetables, and three servings of fruits to give you not only energy but also fiber, vitamins, and minerals. Instead of grabbing a candy bar, satisfy your sweet tooth with fruits that are rich in vitamin C, such as oranges, berries, and melon. Also, vary your vegetable choices to include those that are dark-green and leafy (spinach, broccoli), deep-yellow or orange (carrots, sweet potatoes), and starchy (potatoes, corn).

Eat meat -- and other protein sources.

Protein maintains muscles, and manufactures cells, enzymes, and hormones. It also helps produce the extra blood you need for your baby to develop normally. Poultry, fish, lean meats, low-fat dairy products, and some combinations of grains and legumes, such as rice and chickpeas or black beans, are packed with protein. Eggs and nuts are good sources, too. Aim to include at least three servings of poultry, fish, meat, or legumes, and three or four servings of low-fat or nonfat milk, yogurt, or cheese in your diet every day.

Go for the fats in fish.

Fish is loaded with omega-3 fatty acids, which are instrumental to your baby's vision and brain growth. They also work to improve a woman's blood pressure, blood clotting, and immune response. All seafood provides omega-3 fatty acids, but salmon, bluefish, and trout have the highest concentrations.

Elizabeth M. Ward, R.D., author of the American Dietetic Association's Pregnancy Nutrition: Good Health for You and Your Baby, recommends eating two or three servings of fish a week. Restrict your consumption of swordfish and tuna to twice a week, however, because of their potentially high mercury content.

Take your vitamins.

Prenatal supplements offer vitamins and minerals that you can't always absorb from food. These nutrients serve many functions, from releasing the energy in food to building bones and normalizing heartbeat. Plus, supplements help you meet your increased folic-acid and iron needs during pregnancy. Get your doctor's approval of a supplement before taking it, and never take more than the recommended amount of any nutrient. Too much vitamin A, for instance, can cause birth defects. In addition, avoid all herbal supplements while you're pregnant.

Fuel up on folic acid.

Although folic acid, the man made form of the B vitamin folate, is important throughout pregnancy for producing red blood cells and staving off anemia and premature delivery, it's most critical during the first month, to prevent spina bifida and other neural-tube birth defects. The Centers for Disease Control and Prevention, in fact, estimates that up to 70 percent of neural-tube defects could be prevented with adequate folic-acid intake.

Because many women aren't aware they're expecting until weeks into their pregnancy, it's crucial for all women of childbearing age to get 400 micrograms (mcg) of folic acid daily. During pregnancy, the need jumps to 600 mcg. Synthetic folic acid, which also helps ward off heart disease, is absorbed at nearly twice the rate as the natural form, so get the bulk of your daily requirement in a supplement, says Ward. Breads and cereals fortified with folic acid are excellent sources, too. Lentils, spinach, asparagus, and orange juice are also high-folate foods.

Double up on iron.

Iron helps produce hemoglobin (the part of the red blood cell that carries oxygen from the lungs to the tissues), which is vital to your baby's growth. In your last trimester, the baby builds up iron reserves to last for four to six months after birth, until she starts eating iron-rich solid foods. "Fetuses are efficient parasites," says Joshua A. Copel, M.D., a professor of obstetrics and gynecology and section chief of maternal fetal medicine at the Yale University School of Medicine. "If there's not enough iron, the one who ends up deficient is the mother."

A pregnant woman needs 30 milligrams (mg) of iron daily; many prenatal supplements meet this amount. Still, aim to eat iron-rich foods, such as meat, poultry, seafood, spinach, and potatoes with the skin. Increase your body's iron absorption by eating vitamin C-rich foods (such as broccoli, peppers, or tomatoes) at the same time. Avoid coffee and tea with meals; they inhibit iron absorption. One downside: Iron may lead to constipation. For relief, eat high-fiber foods, such as fruits and vegetables.

Bone up on calcium.

It builds your baby's bones and teeth. If there's not enough in your diet, the fetus will draw calcium from your bones, putting you at risk for osteoporosis later in life. You need a minimum of 1,000 mg a day.

Low-fat or nonfat milk, processed cheeses, and yogurt are great sources (about 300 mg per serving), but there are many calcium-rich nondairy alternatives: calcium-fortified orange juice or tofu; sardines and canned salmon (with the bones); and dark-green, leafy vegetables. If your doctor recommends taking a calcium supplement, steer clear of those made from bonemeal or oyster shells, since they can contain dangerous levels of lead or other pollutants, and those with added vitamin D, an excess of which can harm the fetus. If you take both calcium and iron supplements, do so at different times of day, because they can interfere with each other's absorption.

Drink lots of water.

Your fluid needs increase during pregnancy, partly to keep pace with your burgeoning blood supply, most of which is water. Plain old H2O is your best bet for keeping up with the demand. Water also cools your body, moves nutrients and waste, prevents constipation, and provides a cushion for your baby. Drink at least eight 8-ounce cups of fluid a day; low-fat milk and juice count. A cup a day of coffee or other caffeinated beverages won't hurt the baby, says Copel, but it may dehydrate you. To find out whether you're getting adequate fluids, check your urine: If it's light yellow or clear, you're drinking enough; if it's dark yellow, drink more.

Also, because the kidneys excrete salt actively during pregnancy, be sure to include a moderate amount of iodized salt in your diet, says Copel. Not consuming enough salt during pregnancy may actually predispose you to high blood pressure, and a lack of iodine can cause a form of mental retardation called cretinism in your child.

Beware the bacteria bearers.

During pregnancy, avoid soft cheeses, such as Brie, Camembert, blue, and feta. They may harbor Listeria monocytogenes bacteria, which can lead to dangerous form of food poisoning called listeriosis. (Hard, processed, cream, and cottage cheeses are okay.) Pregnant women are about 20 times more likely than other adults to get listeriosis, which can cause miscarriage, premature delivery, stillbirth, and newborn infections. Also taboo: raw or undercooked meat, poultry, seafood, and eggs, as well as unpasteurized milk and juice. All can pass along food-borne illness.

Finally, be sure to store, handle and prepare foods properly; wash utensils, cutting boards and your hands thoroughly with soap and water; and replace your sponges and dishcloths frequently.

Vary your diet if you're a vegetarian.

"Vegetarians who follow a diet that includes milk and egg products should have no trouble obtaining the necessary nutrients in pregnancy," says Swinney. Just be sure to eat an assortment of grains, fortified cereals, legumes, vegetables, and seeds throughout the day.

Vegans, who eat no animal products, may need vitamin B12, vitamin D, zinc, and calcium supplements prescribed by their doctors. Also, the iron found in plant foods may not be absorbed as well as the iron in meats, warranting a supplement.

If you're a religious Muslim who doesn't eat pork or a religious Jew who doesn't eat pork or shellfish or combine meat and dairy products at the same meal, don't worry. "As long as a diet has a variety of foods from different food groups," says Swinney, "you should get the nutrients you and your baby need." One caution: Some religions have fasting days, but pregnant women should never fast.

If you are lactose intolerant, opt for calcium-rich nondairy foods such as collard greens, figs, and sardines with bones; your doctor may also recommend calcium supplements. Nonprescription drops and tablets containing lactase, the intestinal enzyme that's responsible for lactose digestion, are safe to take with dairy foods during pregnancy, says Ward.

Don't lose sleep over food.

"If you can't stand broccoli or you can't stomach dairy products, simply find alternatives," says Ward. "Avoiding alcohol is absolutely paramount. But avoiding a brownie -- or any other foods you enjoy -- is not."

Parents Magazine