Calories

• Counting calories isn't necessary when you become pregnant, but be aware of the nutritional value of the food you eat. The book "What To Expect When You're Expecting" advises that a woman of average weight consume about 300 calories more than she did in her pre-pregnancy diet. To know if you are getting the right amount of calories, you should gain about 1 pound per week in your second and third trimesters.
  
  Overall, your goal is to eat four to six small meals a day, according to MarchOfDimes.com. The website states that if your pre-pregnancy weight was normal, you should gain 25 to 35 pounds while pregnant. If you were underweight, you should gain 28 to 40 pounds, while overweight women should gain 15 to 25 pounds. Weigh yourself weekly to determine if the diet you are following is adequate.
  
  

Foods to Eat

• Choose healthy calories when deciding on what foods to eat during pregnancy. Sweets and high-fat foods that are high in calories aren't going to pack the nutritional value that you and your baby need. Eat sweets in moderation when you really crave them, but try to substitute fresh fruit for a sweet treat.
  
  When it comes to the foods you eat throughout the day, according to "What To Expect When You're Expecting," your diet should consist of specific requirements. Include three servings each of protein, vitamin C, green leafy and yellow vegetables and yellow fruits. Also eat four servings of calcium, six to 11 servings of whole grains and legumes and two servings of other fruits and vegetables.
  
  Drink at least six to eight 8-oz. glasses of water, juice or milk every day, according to MarchOfDimes.com. To fill in any gaps in your diet, take a prenatal vitamin. It's best to consult your doctor about which vitamin is best for you.
  
  

Foods to Avoid

• Learning which foods to avoid while pregnant is just as important as knowing which are best to eat. The American Pregnancy Association lists all the foods you should not eat while pregnant. Don't eat raw meat and shellfish like sushi, eggs and oysters. Stay away from deli meat unless you heat it to steaming, as there is a risk of listeria. Avoid fish that is high in mercury, smoked refrigerated seafood, soft cheeses, unpasteurized milk and alcohol.