4 Myths About Breastfeeding and Exercise

No doubt you’ve read a lot of opinion blogs about breastfeeding these past weeks. Often this is a topic that divides women and has us on either the offensive, or defensive. I feel that is so unfortunate and such a waste of our emotional resources. Just think if a woman made love to her partner with the same amount of passion with which she argues about feeding methods.

My purpose in writing this is not to debate if women should breastfeed covered in public, or not. Neither is it about guilting mothers who were physically capable of breastfeeding, but for whatever reason chose to formula feed instead. It’s also not about which feeding method is overall superior. Science has made an astounding case that babies are born to consume human milk. We have other options (thank heaven) that centuries ago we did not have. Think how many little lives have been saved because a baby could be nourished by something other than a mother’s milk when breastfeeding doesn’t work out!

My aim in writing this is to dispel some myths about breastfeeding and exercise, and getting back into shape after pregnancy. Let’s cover four concerns that breastfeeding mothers often have.

1.)    After exercise my milk will taste funny or be bad for my baby.

The truth is that only extremely vigorous exercise sessions have proven to dramatically increase lactic acid levels in breast milk. Even with this being true, there is no health concerns with lactic acid being present in your milk and should not cause your baby any problems. If you are concerned about it, just stick to more moderate intensity exercise which won’t produce as much lactic acid in your body. Your baby may not like the salty taste from your sweat, so clean your breasts after exercising and latching on and feeding should be unaffected.

2.)    If I exercise, I’ll lose my milk.

This is not an easy “one size fits all” matter. In women with surplus fat stores, a diet that is controlled along with aerobic exercise has shown a high rate of fat mobilization. This means the gap in energy need is filled by more fat being burned for fuel, all while keeping milk production safe.

Very vigorous exercise has been shown to negatively impact milk supply, especially if you are already pretty low in the body fat department. Also, if you are heavily restricting calories on top of vigorous exercise, a drop in supply is more likely. To rectify this, be sure you are eating enough to counteract the amount of calories expended. To be on the safe side, it’s always better to start with more moderate exercise and then work up gradually as desired. 

Just a few tips on the timing of exercise. Only you know when is the best time of day for you to get it done. Just be sure to empty your breasts by feeding or pumping before workouts to help you stay more comfortable. A supportive bra is also a must. Some women find that doubling up on sports bras really helps hold you down tight enough to exercise comfortably. 

3.)    I will lose my milk if I restrict calories to lose weight.

 As a lactating woman who is exclusively breastfeeding, you are burning up to 500 calories a day just producing milk. That is about what you’d burn during an intense workout-- pretty awesome! With some careful adjustments to diet, you should be able to naturally shed some weight in the first few months even without introducing exercise. Just be sure you are getting your calories from good nutritional sources. Load up on fruits, vegetable, complex carbohydrates, quality protein sources, and healthy fats. I love myfitnesspal for tracking food because they give you a great percentage breakdown of fats, carbs, and protein. Keeping your carb intake to around 40-50% of your calorie intake is a great goal. They don't have a built in way of adjusting for the calories you burn lactating, so just follow the link here for directions on how to manually adjust your calorie goal. 


Most women of average frame should not drop below 1800 calories a day of intake or milk supply could decrease. The key is to discover what your body burns for energy normally, and then add the 500 calories on top of that. Here is an easy online calculator to determine more closely what your resting metabolic rate is. http://www.myfitnesspal.com/tools/bmr-calculator Just be sure to add the extra calories burned by lactating on top of that number. As you introduce solids and your baby is nursing less, the calorie need will drop, so make the needed adjustments at that time.  

4.)    It’s not possible to lose all your baby weight while breastfeeding.

Let me get real for a moment. I thought this was the truth for me. With my first three babies, I breastfed for a year, and I struggled to get my weight down to where I started. In fact, I actually gained at times during the post partum period. I just thought this was how my body worked, and then I had my last baby.

At six months post partum I was about twenty pounds over where I wanted to be. A friend suggested doing Weight Watchers as they had this new easy point system that could be adjusted for breastfeeding mothers. I signed up and with just a little accountability, and being more aware of the foods I was eating, and portion sizes, I dropped twenty pounds in about two months! This was without any consistent exercise regimen.

My conclusion: While being somewhat housebound with a nursing baby, it was easy to eat more than my body needed. I’m highly convinced that I could have achieved this weight loss while nursing my first three babies if I had simply been more aware of what I was putting into my mouth.

I’ve heard quite a few women who say their bodies won’t let go of that last 5-10 pounds until they stop breastfeeding, but this is likely an exception and not the rule. If you are one of those women who is doing all things outlined above and your body is still hanging on to the baby fat, just remember you are a beautiful and amazing mother who is sacrificing to give your baby the best nutrition possible. You are not flawed; you are the amazing you!


If you’d like to know where I got much of my information, look to the Journal of Nutrition (February 1, 1998 Vol. 128 no. 2 386S-389S)