General Requirements

• Most expectant moms require only 300 extra calories a day while pregnant, according to the March of Dimes at marchofdimes.com. This is typically equivalent to an additional healthy snack a day, such as a medium apple and low-fat yogurt, a banana with a spoonful of peanut butter or a hard-boiled egg with a piece of toast.
  
  

Small Meals Are Best

• While you do not necessarily need to eliminate certain food groups from your diet, you should attempt to make choices that will always provide some benefit to your growing baby. You should begin by consuming four to six small meals a day, which not only provides a steady source of vitamins, it also helps to reduce heartburn and discomfort that can accompany eating larger meals.
  
  Your meals should incorporate a healthy mix of whole grains, vegetables, fruits, protein and low-fat milk products. One of the best ways to get the most out of your small meals is to carefully observe serving sizes. For example, a serving of fruit is equivalent in size to a baseball; a serving of whole-wheat pasta is equivalent to what would fill a cupped palm; a serving of meat is equivalent to the palm of a hand; and a serving of milk is the size of a yogurt container.
  
  

Add in Healthy Vitamins and Minerals

• Vitamins such as folate and folic acid are both key to preventing nerve defects and spinal cord abnormalities in babies. An expecting mom should consume 1,000 micrograms of folate or folic acid during pregnancy, according to the Mayo Clinic at mayoclinic.com. Healthy sources include fortified cereal, which can contain up to 400 micrograms per three-quarter cup serving; spinach, which contains 100 micrograms per half cup serving; and Great Northern beans, which contain 90 micrograms per half cup serving.
  
  Calcium is of vital importance to building healthy bones and teeth in your baby as well as preventing the depletion of calcium from your bones for the baby. Pregnant mothers should aim to consume at least 1,000 milligrams of calcium each day from low-fat sources such as yogurt, milk and cheese. If you are lactose-intolerant, other healthy choices include juice, salmon, spinach and cereal.
  
  

Diet Don'ts

• Just as there are healthy foods to eat while pregnant, there are certain ones to avoid. According to healthcastle.com, moms-to-be should avoid seafood high in mercury, artificial sweeteners, certain herbal teas, such as chamomile, and more than three to four servings of caffeine each day.