Breastfeeding Can Lead To Weight Loss Or Weight Gain

Breastfeeding Can Lead To Weight Loss Or Weight Gain

Last update: 29 November, 2017

Motherhood is full of changes and surprises at every step of the way, and breastfeeding is another stage in your body’s transformation. Breastfeeding is proven to be beneficial to both babies and mothers, and helping new moms to get back in shape after pregnancy is often seen as one of the perks.

It’s not all positive, however: instead of helping you to lose weight after pregnancy, breastfeeding can also make you gain pounds.

While it would be tempting to think that the fat in your breast milk comes straight off your thighs, this is a myth. Milk production is related to our diet, hormones and a series of other factors, which do not necessarily have anything to do with your weight at that moment.

If you lose weight while you are breastfeeding, this has to do with the amount of calories that you consume, and the amount that you burn by producing milk. This has given rise to the idea that breastfeeding goes some way towards preventing obesity.

However, this is not the case for all women. Some mothers report weight gain while breastfeeding, and don’t understand why this happens to them and not to others.

Breastfeeding can make you put on weight

To produce milk, a woman’s body burns at least 550 kcal a day. So how can we possibly put on weight while breastfeeding? This change in our body is equivalent to going running for at least an hour a day.

It means that we are drawing on our body’s fat reserves, making it more likely for women to lose weight. In addition, many women eat more healthily than usual.

mom breastfeeding her baby in bed

However, everyone is different, and every woman has a different metabolism. Some people might exercise and eat healthily, but struggle to lose weight in the short term, while others shed pounds with no trouble at all.

Similarly, whether you notice it or not, your diet may change when you are breastfeeding. Tiredness, anxiety and increased exertion can go hand in hand with a higher intake of foods rich in carbohydrates and sugars.

At this stage of our lives, we tend to feel hungrier and sleep less, which can seem like the perfect justification to indulge.

All of this means that weight loss from breastfeeding happens only if we find the right balance between the calories in our diet and the energy we burn to produce milk. That is, if we eat more calories than we use, we will gain weight just the same as if we were not breastfeeding.

Similarly, when we let hunger take over, we consume larger portions of food. For this reason, specialists recommend not going for long periods without a meal or snack, as this can actually lead to weight gain.

However, for some mothers this will still not explain why they are putting on weight while breastfeeding, because there is another factor at play: hormones.

mom eating a salad next to her baby

A lack of estrogen can lead to weight gain while breastfeeding

While a woman is producing milk, her menstrual cycle changes and she goes into a stage of anovulation. This is different for all women. Not ovulating makes your endocrine system release less estrogen, which can lead to a slower metabolism. This means that you will consume fewer calories while at rest.

During this stage, you may also retain liquids, making you feel bloated. This will go away once your menstrual cycle begins again. However, as we know, pregnancy causes major hormonal shifts, which can take time to go back to normal after birth.

Some women suffer from an imbalance known as postpartum thyroiditis. This condition can cause weight loss and weight gain, due to hyperthyroidism or hypothyroidism, respectively.

In general, postpartum thyroiditis clears up around 18 months after birth, around the time that the baby is naturally weaned off breastmilk. However, in around 20% of these women, the condition will not go away on its own.





All cited sources were thoroughly reviewed by our team to ensure their quality, reliability, currency, and validity. The bibliography of this article was considered reliable and of academic or scientific accuracy.

  • Muller JM., Enderle J., Bosy Westphal AB., Changes in energy expenditure with weight gain and weight loss in humans. Curr Obes Rep, 2016. 5 (4): 413-423.
  • Morselli E., Souza Santos R., Gao S., Ávalos Y., et al., Impact of estrogens and estrogen receptor in brain lipid metabolism. Am J Physiol Endocrinol Metab, 2018.

This text is provided for informational purposes only and does not replace consultation with a professional. If in doubt, consult your specialist.