Pregnancy isn't a time to restrict your calories, but neither is it a license to gain as much weight as you want. For the optimal health of both you and the baby, you should gain within the recommended range for your body type. Do so by eating nutritious foods from all five food groups. Never attempt to lose weight during pregnancy, as this can cause your body to release substances called ketones (KEE-tones) that are harmful to the fetus. The amount of weight you're advised to gain will depend on your height and how much you weighed before you became pregnant. Women who were underweight should add between 28 and 40 pounds; women of normal weight should aim for 25 to 35 extra pounds; those who were overweight should increase by 15 to 25 pounds; and obese women should add just 15 pounds. These ranges are for those carrying one child. If you're expecting twins or multiple births, 35 to 45 pounds is appropriate. During pregnancy, don't be discouraged about your appearance. Remember that 15 pounds or more of your weight can easily be attributed to the baby, the placenta, and the amniotic fluid. This portion will disappear right after the birth; the rest you can lose gradually as you get back on your feet.