If your weight is what's considered in the “normal” range (that means you have a body mass index of 18 to 25) before you conceive, the American College of Obstetricians and Gynecologists (ACOG) recommends a gain of 25 to 35 pounds throughout pregnancy. You want to aim to add 3 to 5 pounds during your first trimester and then 1 to 2 pounds every week after. If you’re underweight at the time of conception, you should gain 28 to 40 pounds, and if you’re overweight, try to keep it to 15 to 25 pounds.
No matter what your starting weight is, your goal is to keep the gain as steady as possible. Baby needs a daily supply of nutrients, and those come from the foods you eat. Don’t worry if your weight gain fluctuates a bit from week to week, but contact your doctor if you suddenly gain or lose a noticeable amount of weight, especially in the third trimester. This can be a sign of preeclampsia.
You might think you’ll have no problem staying within your “gain range,” but don't be surprised at how quickly the pounds can pile on. It can be hard, especially when those cravings kick in, but it's important to remember that pregnancy isn’t an excuse to pig out. To stick to the weight gain guidelines, you only need to eat an extra 300 calories a day—that's the equivalent of a very small bagel, without cream cheese. But instead of stressing out about the quantities you're eating, focus on eating quality foods and steering clear of junk foods that pack on pounds without adding nutrients.