Grains provide essential carbohydrates, your body's main source of energy. Many whole-grain and enriched products also contain fiber, iron, B vitamins, various minerals and protein. Fortified cereals can help you get enough folic acid.

How much: Choose six to nine servings a day. If that sounds like a lot, relax. It may not be as much as you think.

One serving equals:

• 1/2 to 1 cup cold cereal
• 1/2 cup cooked cereal, pasta or rice
• 1 slice bread
• 1/2 English muffin
• 1/2 small bagel
• 6 crackers

Trade sugary cereal and white bread for whole-grain cereals, brown rice, whole-wheat pasta and whole-grain bread. Feature wild rice or barley in soups, stews, casseroles and salads. Look for products that list whole grains first in the ingredients list (such as whole-wheat flour, not simply wheat flour).

Fruits and vegetables provide various vitamins and minerals, as well as fiber to aid digestion. Vitamin C, found in many fruits and vegetables, helps you absorb iron. It also promotes healthy gums and other tissues for both you and your baby. Dark green vegetables have vitamin A, iron and folate — other important nutrients during pregnancy.

How much: Choose three or more servings of fruit and four or more servings of veggies a day. It's easy! Top your cereal with slices of fresh fruit. Make a veggie pizza. Sneak extra vegetables into your casserole.

One serving equals:

• 1 medium-sized piece of fruit
• 1/2 cup fresh, frozen or canned fruit
• 1/4 cup dried fruit
• 1 cup raw, leafy vegetables
• 1/2 to 1 cup cooked or other raw vegetables
• 1/2 cup fruit or vegetable juice
• 1 small baked potato

If you're tired of the standard apples, oranges, green beans and corn, branch out. Try apricots, mango, pineapple, sweet potatoes, winter squash or asparagus. Make trail mix with a variety of dried fruit. If you drink fruit juice, limit the number of daily servings. Too much fruit juice can lead to undesired weight gain.

The calcium in dairy products and calcium-fortified soy milk helps build your baby's bones and teeth. Dairy products also have vitamin A, vitamin D and protein.

How much: Choose four or more servings a day. Drink the milk in your cereal bowl. Eat yogurt for your afternoon snack. Have a glass of milk with dinner. Add cheese to a salad.

One serving equals:

• 1 cup skim milk
• 1 cup yogurt
• 2 ounces natural cheese (about the size of six dice)
• 2 ounces processed cheese

If you have trouble digesting dairy products, get creative. Try calcium-fortified orange juice. Experiment with lactose-reduced or lactose-free products. Take a lactase enzyme preparation when you eat or drink dairy products.

Foods in this group have plenty of protein, as well as B vitamins and iron. Protein is crucial for your baby's growth, especially during the second and third trimesters.

How much: Choose two or more servings of protein-rich foods a day. Eat peanut butter toast for breakfast. Make scrambled eggs or an omelet for lunch. Serve a salmon fillet for dinner. Add chickpeas or black beans to your salad. Snack on a handful of soy nuts..

One serving equals:

• 2 to 3 ounces of cooked lean meat, poultry or fish (about the size of a deck of cards)
• 1/2 cup cooked dried beans
• 1 egg
• 1/2 cup tofu
• 1/3 cup nuts
• 2 tablespoons peanut butter

If your traditional sources of protein no longer appeal to you — especially during the first trimester — experiment with other options.

Seafood can be a great source of protein and iron — crucial nutrients for your baby's growth and development. And the omega-3 fatty acids in many fish can help promote your baby's brain development. In fact, a British study published in February 2007 suggests that skimping on seafood during pregnancy may contribute to poor verbal skills, behavioral problems and other developmental issues during childhood.

But some types of seafood — particularly large, predatory fish such as swordfish, shark, king mackerel and tilefish — contain potentially high levels of mercury. Although the mercury in seafood isn't a concern for most adults, special precautions apply if you're pregnant or planning to become pregnant. During pregnancy, too much mercury may damage your baby's developing brain and nervous system.

What's safe to eat? Some types of seafood contain little mercury. The Food and Drug Administration (FDA) says pregnant women can safely eat up to 12 ounces a week (two average meals) of:

• Shrimp
• Canned light tuna (limit albacore tuna and tuna steak to no more than 6 ounces a week)
• Salmon
• Pollock
• Catfish

But some scientists suspect that these limits are too low. In the British study, women who ate 12 ounces or less of seafood a week were more likely to have children with verbal or other communication problems at age 3, and behavioral problems and trouble with fine motor skills by ages 7 and 8. No negative effects were noted for women who ate more seafood than the FDA-approved guidelines.

Starches are breads, grains, cereals, pastas, and some vegetables (such as potatoes or corn). They give your body energy, vitamins, minerals, and fiber. Whole grain starches are healthier because they have more vitamins, minerals, and fiber. If you have more than one serving at a meal, you can choose several different starches or have two or three servings of one starch.

There's no magical formula for pregnancy nutrition. In fact, during pregnancy the basic principles of healthy eating remain the same — plenty of fruits, vegetables and whole grains and lean sources of protein. However, a few nutrients do deserve special attention. Here's what tops the list.

Folate and folic acid: Folate is a B vitamin that helps prevent neural tube defects, serious abnormalities of the brain and spinal cord. Lack of folate also may increase the risk of preterm delivery, low birth weight and poor fetal growth. The synthetic form of folate found in supplements and fortified foods is known as folic acid.

How much you need: 1 milligram (1,000 micrograms) of folate or folic acid a day before conception and during pregnancy. Good sources: Fortified cereals are great sources of folic acid. Leafy green vegetables, citrus fruits, and dried beans and peas are good sources of naturally occurring folate.

Calcium: You and your baby need calcium for strong bones and teeth. Calcium also helps your circulatory, muscular and nervous systems run normally. If there's not enough calcium in your diet, the calcium your baby needs will be taken from your bones.

How much you need: 1,000 milligrams a day. Good sources: Dairy products are the richest sources of calcium. Many fruit juices and breakfast cereals are fortified with calcium.

Iron: Your body uses iron to make hemoglobin, a protein in the red blood cells that carries oxygen to your tissues. During pregnancy — when your blood volume expands to accommodate changes in your body and your baby must make his or her entire blood supply — your need for iron nearly doubles.

If you don't get enough iron, you may become fatigued and more susceptible to infections. The risk of preterm delivery and low birth weight also may be higher.

How much you need: 27 milligrams of iron a day. Good sources: Lean red meat, poultry and fish are good sources of iron. Iron-fortified breakfast cereals, nuts and dried fruit are other options.

Vitamin D: Vitamin D is found in a small number of foods but we get most of our vitamin D from summer sunlight - if you're out in the sun, remember to take care not to burn!

If you are of Asian origin, if you always cover up all your skin when you're outside, or if you rarely get outdoors, you may be particularly short of vitamin D. Ask your GP for more information.

Supplements: Even women who eat healthfully every day may miss out on key nutrients. A daily prenatal vitamin — ideally starting three months before conception — can help fill any gaps. Your health care provider may recommend special supplements if you follow a strict vegetarian diet or have any chronic health conditions. If you're considering an herbal supplement, make sure you have your health care provider's OK to take the supplement during pregnancy.

Sorry, there are no minimum requirements for fats and sweets. It's OK to indulge once in a while, as long as you're getting the nutrients you need and your weight gain is on target. To avoid going overboard, keep an eye on portion size.