Too Much or Not Enough? The First Trimester Weight Gaining Guide


There is some confusion over what exactly constitutes healthy weight gain during pregnancy. Some refer to pregnancy as an excuse to ‘eat for two’ and throw all normal diet rules out the window, while others might follow a diet too stringently for fear of not being able to lose the weight. Statistics show that about half of women of average weight, and two-thirds of overweight women gain too much weight during pregnancy! Yet, both sides of the spectrum, too much weight gain or not enough, pose health risks to both the pregnant mother and the unborn child.

Benefits of Watching Your Diet Starting in Your First Trimester

Though we do not suggest legitimate dieting during pregnancy, there are several reasons to keep your diet in good shape. Overweight mothers are likely to give birth to overweight children, who then face a higher risk of cancer than average weight infants. The women themselves are more likely to develop chronic hypertension, diabetes, experience more aches and pains, and face a possible cesarean section delivery. Babies born to underweight women are at risk for preterm delivery, low birth weight, and diabetes later in life. Infants born from underweight mothers face a mortality rate of 3.9% compared to a 1.2% rate of those born to mothers who gained the suggested amount of weight.

Gaining Healthy Weight

Women at risk for gaining too much weight during pregnancy usually start this trend in the first trimester, when the suggested weight gain is only about 3-6 pounds. Dramatically increasing caloric intake during this time is not necessary— 100 additional calories per day is all that is needed to get your baby the nourishment it needs. These 100 calories can be easily incorporated into the diet through the addition of a small baked potato, an apple, or half of an avocado each day. When progressing into the second and third trimesters, an extra 300 calories per day is needed and this should result in 1-2 pounds gained per week throughout the rest of the pregnancy. Caloric intake can be increased by adding full fat cheese to scrambled eggs, peanut butter to smoothies or toast, and avocados to salads. A few healthy, 300 calorie snack examples include one whole grain pita pocket with 2-3 Tbsp of hummus, three scrambled or hard boiled eggs, or one cup of beans with 1/2 a cup of brown rice.

By The Numbers

In total, gaining approximately 25-35 pounds is the benchmark for a healthy pregnancy. Of course, if you are already underweight this should be boosted to 28-40 pounds, and if you’re overweight only 15-25 additional pounds is necessary. The key point in order to effectively nourish your baby while gaining the appropriate amount of weight is to focus on consuming enough calories necessary for your baby to adequately develop, while making those calories high quality and nutrient dense. This means avoiding fast food and empty calories from junk food as much as possible.

Don’t forget to exercise! Women who regularly exercise gain less fat mass and find it is easier to get back to their pre-pregnancy weight. Breastfeeding is known to speed up weight loss but is more of a quick fix, and does not provide the lasting results that exercise does. The goal post pregnancy is to lose about 1 to 2 pounds per week to avoid affecting milk supply if you are breastfeeding.


  • During the first trimester add a healthy 100 calorie snack daily. An average of 3-6 pounds should be gained during this 12 week window.
  • Entering the second trimester, consume an additional 300 calories per day until delivery. This should result in an additional 1-2 pounds per week.
  • For the average woman, a total weight gain 25-35 pounds is recommended for a healthy pregnancy.

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