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Oleg Kozlov

The question

I'm pregnant - and in the midst of a successful low-carb diet. First, how should I change my eating habits for a healthy pregnancy, and second, is it possible to 'eat for two' (or three!) and still lose weight?

The answer

I'm afraid you will have to put your weight loss plan on hold. Now is not the time to be restricting your body - and your developing baby - calories and nutrients. Gaining the recommended amount of weight during pregnancy - not too little or too much - is linked with the best health outcomes for mother and baby.

Weight gain guidelines are based on your body mass index (BMI) before pregnancy. If your pre-pregnancy BMI was in the healthy range (20-25) you are advised to gain 25 to 35 pounds; if you were overweight when you became pregnant (BMI 25.9 - 29.9) you should gain 15 to 25 pounds.

Obese women (BMI of 30 or greater) should gain 11 to 20 pounds during pregnancy. (Use an online calculator to determine your BMI.)

During pregnancy, you need extra calories to support the growth of your baby, the placenta, as well the expansion of your own body's tissues. But it doesn't take a lot of food: calorie needs increase by 300 in the second and third trimesters. Since energy expenditure changes only slightly and weight gain is minor during the first trimester, calorie needs don't change until trimester two.

Eating more calories than you need will increase the likelihood of gaining too much weight and the risk of lifelong weight problems.

Start changing your diet right now by gradually adding back healthy carbohydrate foods such as whole grains, fruit, milk and yogurt.

A low carb diet is also low in folate, a B vitamin that helps reduce the risk of neural tube defects (NTDs) in the developing fetus. (NTDs are serious birth defects caused by the incomplete development of the brain, spinal cord and/or their protective coverings that occur around the fourth week of pregnancy.)

If you are not already doing so, take a multivitamin with 0.4 to 1 milligrams of folic acid throughout pregnancy and breastfeeding.

To get the iron you need during pregnancy - 27 milligrams - choose a multivitamin with 16 to 27 milligrams of iron and add iron-rich foods to your diet. Beef, shrimp, sardines and trout are good sources of iron.

Plant sources include legumes, pumpkin seeds, enriched breakfast cereals, nuts, raisins and prune juice.

Include 5 to 12 ounces of oily fish in your weekly diet to increase your intake of DHA, an omega-3 fat important for brain and eye development during pregnancy and breastfeeding. Good choices that are low in mercury include salmon, trout, sardines, herring, and Atlantic mackerel.

If you don't eat fish, consider taking a fish oil supplement. Avoid fish liver oil supplements which are often high in vitamin A.

Send dietitian Leslie Beck your questions at She will answer select questions, which could appear in The Globe and Mail and/or on The Globe and Mail web site. Your name will not be published if your question is chosen.

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The content provided in The Globe and Mail's Ask a Health Expert centre is for information purposes only and is neither intended to be relied upon nor to be a substitute for professional medical advice, diagnosis or treatment.