Losing Baby Weight - Downfalls to Dieting While Breastfeeding

by Guest Contributor May 11, 2023

Pregnancy, childbirth, and breastfeeding during the postpartum period are times of major and rapid changes physically and emotionally. During the nine months of growing your baby, your body changes shape and size. After giving birth, your body continues to change as hormones shift yet again and you begin to nurse your baby or pump milk to give to your growing little one. Some changes may be welcomed and exciting while other changes are uncomfortable or feel difficult emotionally.

During pregnancy, you gain weight as your baby grows. You are also growing the placenta and retaining more fluids.

By the end of your pregnancy, the placenta weighs about 0.5 to 1 kilograms.
Extra water is retained by your body during pregnancy. The increase supports cell function as well as oxygen delivery and helps flush toxins out. The volume of water you retain can be up to 1.4 kilograms.(1)
Plasma volume increases by 50%.(2) The main role of plasma, which is the largest part of your blood, is to carry and deliver nutrients and hormones where they are needed in the body and to remove waste deposited in plasma from other cells. It supports your organs as they change and the growing needs of the placenta to support your baby as they develop.
Your baby’s weight by the end of your pregnancy is likely about 3.2 - 3.7 kilograms
Your uterus expands to accommodate your growing baby and the muscle layer grows adding on about 0.9 more kilograms.
Your breasts are preparing to make milk to feed your baby after birth. They will gain anywhere from 0.4 - 0.9 kilograms during pregnancy.(3)
Amniotic fluid weighs about 0.9 kilograms. It cushions your baby while they move and grow in the womb.
2.7 - 3.6 kilograms is due to increased fat stores. This provides a reserve of calories for you and your baby during the rapid growth period during the last several weeks of pregnancy. Most of the stores are on your back, thighs and belly.(4)

The amount of weight you gain during pregnancy depends on many factors. Practitioners use Body Mass Index (BMI) to help determine an amount of weight gain that would be advisable. Body Mass Index is a calculation of your weight divided by height squared.(5) There are plenty of BMI calculators online where you input your weight and height and it will do the calculations for you.

BMI categories:(6)

Underweight = <18.5
Normal weight = 18.5–24.9
Overweight = 25–29.9
Obesity = BMI of 30 or greater

Weight gain recommendations during pregnancy:(7)

Underweight - 12 - 18 kilograms
Normal weight - 11 - 16 kilograms
Overweight - 7 - 11 kilograms
Obese - 5 - 9 kilograms

It is typical to lose weight after the birth of your baby. You no longer have your little one on the inside, the placenta is delivered and there is no more amniotic fluid. As you are establishing breastfeeding, it is recommended to not focus on any additional weight loss. The average amount of weight retained postpartum is 1.1 - 2.3 kilograms and ¼ of women will retain 5 kilograms or more.(8) Weight seems to stabilize between 6 - 12 months postpartum.

Postpartum weight loss

The best approach to weight loss during breastfeeding is to focus on nutrition and exercise or movement. Breastfeeding burns approximately 300 - 500 calories if you are exclusively breastfeeding. In one study, women who exclusively breastfed for 3 months lost significantly more weight than people who didn’t exclusively breastfeed during the first three months postpartum. The World Health Organization recommends exclusive breastfeeding for the first 6 months of a baby’s life.(9)

Extreme diets or exercise regimens can negatively impact your own nutrition and therefore can affect your milk. Your nutritional status impacts your gut health which then affects the milk you make. Excessive exercise can temporarily increase lactic acid in breast milk giving it a more bitter taste, but this seems to be short lived.(10) Moderate exercise does not cause the same result and has shown no negative impacts for the baby or parent. When you restrict calories too much or are not eating nutritiously dense foods, milk supply can decrease.

Healthy ways to lose weight while breastfeeding

Eat whole foods that do not come in a package. These will be full of nutrition and contribute to better overall health. Eat the rainbow- include lots of colorful, fresh vegetables and greens in your meals.
Continue to take your prenatal vitamins to ensure you are getting all the vitamins and minerals necessary for you and your baby. Some people take supportive supplements for milk production as well. All of Legendairy Milk’s breastfeeding supplements are Fenugreek free. Some moms and babies experience stomach discomfort from fenugreek and should not be used if you have a thyroid imbalance.
Drink plenty of liquids to replace those lost when you sweat during exercise.
Breastfeed before exercising so you are more comfortable during your workout.
Your body may have changed and need extra time or support to avoid injury while exercising. Pay attention to what your body is telling you. Start slow with exercise and work up to more intensity as your body is ready.

Why am I not losing weight?

Your hormones go through major shifts during pregnancy, birth and breastfeeding. If you find you have gained weight or just aren’t able to lose it, despite trying, after your baby arrives, you may need to get in touch with your SACLC/IBCLC to dig deeper for why. Sometimes hormones are out of balance after having your baby. There are often indicators before your pregnancy, but they may not have been significant enough to be picked up on before now. Postpartum thyroiditis often surfaces during the first year postpartum.(11) Making changes to the foods you eat will help improve gut function which helps balance hormones and can improve thyroid function.(12)

Improvements to overall health are longer lasting and become a new lifestyle that you, your baby and the whole family can benefit from. Exercise can reduce stress and increase your energy levels so you have more energy to play with your baby. It contributes to better sleep and a happier state of mind.

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