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Nutrition and Weight Gain

What should I be eating?

To gain weight and meet the needs of the growing baby, certain vitamins and minerals are very important during pregnancy. In order to meet these needs, it is recommended you follow Canada’s Food Guide for Healthy Eating and eat an extra two to three food guide servings daily.

If you are concerned that you are not meeting your requirements, ask your doctor to refer you to the dietitian in Obstetrics at Mount Sinai.

To help visualize serving sizes, you can use the following tips to approximate size:

  • 1 cup = the size of a woman’s fist
  • 2 ozs. meat (60 g) = the size of a deck of cards
  • 3 oz. (90 g) = about the size of a palm of a woman’s hand
  • 1.75 oz. cheese (50 g) = the size of two thumbs
  • 1 tbsp = to the size of the 1st knuckle of a thumb

Protein is very important to help with the development of baby’s tissues, placenta growth, increasing blood volume and to help with the mother’s protein stores for pregnancy and breastfeeding. By your second trimester you need an extra 25 g of protein every day. The best sources of protein include meats and meat alternatives, and dairy/alternatives. Try to make sure you get a minimum of two servings from each of these groups every day.

Iron requirements almost double in pregnancy to 27 mg each day. Iron can be found in the meats and alternative food groups, as well as in grains. The iron from meats is best used by the body. In order to help the iron from grains to be used, eat grains with a Vitamin C rich food and not at the same time as a calcium rich food (milk product), or coffee/tea.

Both calcium and vitamin D are very important to help build babies’ bones. Requirements do not increase in pregnancy, but it is important to ensure that 1000 mg calcium and Vitamin D is consumed. Calcium can be found in milk and milk alternatives, as well in smaller amounts in other foods. Vitamin D found in milk helps the body use the calcium.

Requirements increase to 0.6 mg each day to decrease the risk of neural tube defects, and help with the mother’s growing blood volume and growth of baby’s tissues. Folate is found in prenatal vitamins. Folate can be found in the diet in legumes (beans and peas), seeds, green vegetables and citrus juices.

Essential fatty acids help with the development of the baby’s visual and neural systems. It is found mostly in fish, vegetable oils (canola and soybean), and walnuts.

Calorie intake increases in pregnancy, although “eating for two” is not the idea. A woman’s diet needs to increase by about 100 calories in the 1st trimester, and by 300 calories in the 2nd and 3rd trimester. To ensure that you are meeting all your calorie needs, plus the other nutrients mentioned above, aim to meet the recommended intake of each of the four food groups according to Canada’s Food Guide plus an additional two to three servings every day.

Take a multivitamin daily before and during your pregnancy. A daily multivitamin provides important vitamins and minerals, including folic acid and iron. Some women need more folic acid or iron. It is important to take only what is recommended by your health care provider. Check the label on your multivitamin to make sure it contains what and how much your health care provider recommends. Not all prenatal vitamins and multivitamins are the same.

Folic acid helps cells develop and reduces the risk of some birth defects. Folic acid is important early in pregnancy. Folic acid is recommended for:

  • All women who could get pregnant
  • All pregnant women
  • All breastfeeding women

Pregnant women often have difficulty getting enough iron from their food. A daily multivitamin can help you get enough iron. Talk to your health care provider if you have side effects from the multivitamin.

How much weight should I gain?

Weight gain is normal and healthy during pregnancy. Weight gain recommendations vary depending on different factors.

It is important to gain a healthy amount of weight for you and your growing baby. This amount depends on your weight before you were pregnant and other factors (e.g. teen pregnancy, pregnant with more than one baby, etc.) The amount of weight you gain includes the weight of your baby, your uterus, the amniotic fluid, etc. A healthy diet plus physical activity during pregnancy will help you gain weight gradually.

There are risks to gaining too much or too little weight during your pregnancy. Talk to your health care provider about how much weight you should gain.

It is important to pay attention to how quickly you gain weight. Weight gain is usually slow during the first three months. Most weight gain will happen in the second and third trimesters. Gaining weight at a steady pace is a sign of a healthy pregnancy. Talk to your health care provider if you are gaining a lot more than 0.4 kg (1 pound) a week, or a lot less.


Constipation is very common in pregnancy and in most cases can be treated or prevented with changes to your diet, increased activity and increased fluid intake.

Prevention and Treatment

  • Aim for a minimum of 25g of fibre in your diet every day.
  • A high-fibre food will have at least 5g per serving.
  • Examples of high fibre fruit and vegetables: apples, berries, kiwis, mango, oranges, pears, corn, peas, potato (with skin on), sweet potato, broccoli, brussel sprouts, carrot, eggplant and turnips.
  • Dried fruits: raisins, dates, apricots, and prunes, either plain or in desserts and breads.
  • Dried peas and beans and nuts and seeds.
  • Whole-grain breads and cereals: brown rice, bran buds, high-fibre cereals, whole wheat pasta, whole wheat breads, oats.
  • Psyllium (sold under several brand names), 1 teaspoon to 1 tablespoon once or twice a day in a glass of water
  • Eat at least five servings of whole grain products daily. Choose whole wheat pasta and whole grain breads.
  • Aim for seven to eight servings of fruits and vegetables every day.
  • Eat fruit rather than drinking juice.
  • Drink plenty of fluids daily. A minimum of six to eight cups of fluid is recommended.

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