Why You Shouldn't Try to Lose Weight During Pregnancy

Pregnancy is a time of lots of changes in your body—some exciting and joyful, and some more uncomfortable. One area that pregnant parents sometimes struggle with is weight gain. Gaining weight during pregnancy is normal, expected, and healthy. But that doesn’t mean we always feel okay about it—and it's not shameful if you find this challenging. Gaining weight during pregnancy can be especially triggering if you have a history of an eating disorder or body dysmorphia.

If you are struggling with your emotions surrounding weight gain during pregnancy, you are far from alone. That said, it's very important that you don’t diet or try to lose weight during pregnancy. Doing so can have negative impacts on your health and the health of your baby. Still, if you are feeling triggered by pregnancy weight gain, you need support and tips for how to manage your feelings.

Here, we’ll discuss why gaining weight during pregnancy is important, how much weight to gain, and nutritious food choices you can make. We’ll also address how to manage your feelings if you are finding weight gain during pregnancy triggering.

Why Is Weight Gain Important During Pregnancy?

Gaining weight during pregnancy supports the evolutions your body is going through, and also helps your baby grow from a tiny cluster of cells to a newborn infant.

“It is important to gain a healthy amount of weight during pregnancy because your body changes in many ways,” says Shivani Patel, MD, OB-GYN at UT Southwestern Medical Center.  First, says Dr. Patel, your basal metabolic rate (the amount of energy/calories needed to perform basic tasks) increases by up to 20 percent during pregnancy because you are spending more energy growing another human. The fat that accumulates in your abdomen, breasts, and hips is “normal and necessary for pregnancy and the postpartum period,” Dr. Patel describes.

Your body is also growing to accommodate your baby and help them develop, says Ellen Smead, CNM, certified nurse-midwife at Pediatrix Medical Group in Atlanta, Georgia. Your uterus increases substantially in size as your baby grows, and you actually create a whole new organ to sustain your baby—your placenta, which helps feed needed nutrients to your baby. “These new organs are created specifically for pregnancy, and therefore create a higher demand from the body,” Smead describes.

Not all of the weight you gain is because of fat, but is related to the other changes that are happening in your body, as well as the growth of your baby. The National Library of Medicine breaks it down this way:

• Your baby: 8 pounds
• Placenta: 2-3 pounds
• Amniotic fluid: 2-3 pounds
• Breast tissue: 2-3 pounds
• Blood supply: 4 pounds
• Fat storage: 5-9 pounds
• Growth of the uterus: 2-5 pounds

How Much Weight You Should Expect to Gain During Pregnancy

Weight gain guidelines during pregnancy are just that—guidelines. For the most part, your focus should be on eating when you are hungry, and opting for nutrient-dense food when possible. “In general, I don’t recommend hyper-focusing on weight gain during pregnancy,” says Smead. “Every pregnant person’s body is a little different and some will gain more than others with similar diets.”

Still, understanding the basic guidelines for weight gain during pregnancy can be helpful. According to the Centers for Disease Control and Prevention (CDC), the amount of weight to gain during pregnancy depends in part on your weight before getting pregnant. For example, if you were underweight, it might be appropriate to gain between 28-40 pounds. If you were an average weight, a 25-35 pound gain might make sense. If you were overweight or obese, a smaller weight gain might work best for your pregnancy.

As the American College of Obstetricians and Gynecologists (ACOG) notes, weight gain during pregnancy is usually minimal in the first trimester, with many people only gaining between one and five pounds. But things usually pick up in the second and third trimesters, with most folks gaining about half a pound to a pound each week. Generally, as per ACOG, you'll need about 340 extra calories a day in the second trimester, and 450 calories a day in the third.

Again, though, it’s best to keep your focus on healthy eating rather than counting calories or focusing on weight gain. According to the U.S. Department of Health and Human Services, when you are pregnant, you need more protein, folic acid, iodine, and choline than you did before. You also need to ensure you’re getting plenty of vitamin D, calcium, fiber, and potassium. Some of these nutrients can be acquired through a prenatal vitamin, but a diet rich in these elements is also essential. That means eating plenty of fruits, veggies, whole grains, proteins, and healthy fats.

Risks of Trying to Lose Weight During Pregnancy

The hard truth is that losing weight or not gaining adequate amounts of weight can have negative effects on both you and your baby. “Losing weight during pregnancy carries risks of inadequate fetal growth and not creating the normal maternal body changes needed for pregnancy and the postpartum period,” Dr. Patel explains. “Of these, we worry most about poor fetal growth.”

Indeed, studies have found that people who are underweight or don’t gain enough weight have a higher risk of giving birth prematurely. They also have a higher risk of having a baby who is smaller for their gestational age.

As Smead points out, having a baby with these issues can have immediate and long-term impacts. “When a baby is born preterm or at a low birth weight, there is a higher likelihood for breastfeeding problems and other illnesses later in infant and child life,” she explains. She also points to research that shows a relationship between low birth weights and developmental delays.

Ways to Cope if Gaining Weight During Pregnancy Is Triggering

If you are someone who has a past history of eating disorders, body dysmorphia, or simply has experienced body image issues, gaining weight during pregnancy can be challenging. It’s completely normal and okay for this to bring up all kinds of feelings for you. You should know that your feelings are valid and understandable.

Smead says that if you are feeling triggered by weight gain during pregnancy, you should consider addressing this with a health care provider. “Often it is a good idea to discuss this at the first visit, and then throughout the pregnancy if there is a concern,” she says. Additionally, she says that it may make sense to do “blind weigh-ins” during your prenatal visits.

“It is appropriate in this circumstance for a pregnant person to not have to see their weight during any of their visits,” Smead suggests. “Usually charts can be flagged so that all involved in the care team are aware to not verbalize any weight during a visit.”

Dr. Patel says that if you have a strong history of eating disorder, it may be best to seek psychiatric or psychological care for your eating disorder during pregnancy, if you aren’t already doing so. “Even if people feel that part of their medical history is no longer a problem, pregnancy can be triggering,” she says. “Understanding what the triggers may be and having a plan for addressing them during pregnancy is important.”

If you aren’t pregnant yet, but considering it, Dr. Patel recommends seeking preconception counseling with a health care provider to understand your history and how pregnancy might impact your eating disorder. It’s possible a health care provider and mental health provider can jointly develop a plan for addressing any issues that come up during a potential pregnancy.

When to Ask for Help

During pregnancy, you will be meeting with a health care provider at regular intervals, so they will usually be able to tell if your weight gain—or lack of weight gain—is becoming a concern. But sometimes issues will arise outside of these visits.

“If during pregnancy you are experiencing light headedness, dizziness or are nauseous to the point of not being able to keep any food or liquids down, it’s a good idea to call,” Smead suggests. “Alternatively, if you notice you gain five pounds in one week, it would be recommended to call and be seen for a check in and to confirm accuracy of scales or determine if you are experiencing a significant amount of edema.”   

Most importantly, please stay in touch with a health care provider and/or therapist regarding any emotions and triggers you are experiencing regarding body image, weight gain, or disordered eating. They are here to support you, and to keep your mind and body as healthy as possible during this life transition.