Putting on the pounds

In the first 13 weeks of pregnancy, also called the first trimester, most people don't need to gain much weight. This is good news if you have upset stomach or vomiting due to pregnancy, also known as morning sickness.

If you start out at a healthy weight, you need to gain only about 1 to 4 pounds (0.5 to 1.8 kilograms) in the first few months of pregnancy. You can do this by eating a nutritious diet — no extra calories are needed. A nutritious diet includes plenty of fruits, vegetables, whole grains, lean protein and healthy fats.

Steady weight gain is more important during weeks 14 to 40 of a full-term pregnancy. This timespan includes the second and third trimesters of pregnancy. Steady weight gain during this time is especially important if you start out at a healthy weight or you're underweight. According to the pregnancy guidelines, you should try to gain about 1 pound (0.5 kilogram) a week until delivery. An extra 300 calories a day might be enough to help you meet this goal. You can get around 300 calories from a sandwich and a glass of skim milk.

For people who are overweight or obese, the guidelines suggest a weight gain of about 1/2 pound (0.2 kilogram) a week in the second and third trimesters. Try adding a glass of low-fat milk or an ounce of cheese and a serving of fresh fruit to your diet.