This is a two part series on breastfeeding I’ve been wanting to write for a long time. This is part one on milk supply. There is a good bit of evidence based articles on the internet full of helpful breastfeeding information. My goal with this series is to provide information that’s a little harder to find when you start digging around on the internet. I don’t know everything about breastfeeding and I am certainly not an IBCLC. What I’m sharing in this series is a combination of my nursing knowledge, a lot of time spent researching, and my experience as a mama. I hope you find it empowering & encouraging!
As a culture, I firmly believe there needs to be a lot more support for breastfeeding women. Our maternity leave policies suck in the US. I think expecting a mom to return to work after only 12 weeks (or often, much less) with her baby and still exclusively breastfeed is a lot to ask. It can be done, but I think maternity leave policies are a huge barrier for women and certainly aren’t supportive of a long term breastfeeding journey.
Moreover, I think our diet/wellness culture is another huge barrier – the pressure to eat x way or x much and lose the baby weight and “bounce” back and blah blah blah is extremely harmful when it comes to mental health and establishing + maintaining an adequate milk supply. There are of course many more barriers, but those are two big ones that stand out in my mind. I’m going to focus more on the latter in addition to touching on a few other things in this post because unfortunately, maternity leave policies aren’t changing any time soon and we don’t have as much control over that. But we can control how we care for ourselves!
In addition to maternity leave policies, there are also other things out of your control when it comes to breastfeeding. This list is not exhaustive, but factors such as retained placenta, insufficient glandular tissue (IGT), baby’s latch & ability to suckle, mental health, insulin resistance (research is emerging with this) can all impact breastfeeding. If you’ve experienced any of these issues, big hugs to you. I want to note these here (and there are surely more reasons out of your control) before we talk about things you have more control over.
**I am going to miss things in this post and there is always exceptions given individual circumstances. Breastfeeding is such a vulnerable, touchy topic. My hope is that this post is a source of encouragement for you no matter what your history or current circumstances are with breastfeeding. You are doing the best you can with the information & support you have. Remember that! You’re doing great.
Things More in Your Control
- nursing frequency
- pumping (and most importantly replacing bottle feeds with pumping)
- sleep & stress (to some extent)
- support & access to evidence based information
Adequate energy & macronutrients (carbs, proteins and fats) is pivotal when it comes to maintaining an adequate breastmilk supply. Again, there are things out of your control leading to low milk supply – but to make sure you are doing everything you can to begin with, nourishing your body so you can make milk is essential.
We live in a culture that emphasizes smaller body sizes and doesn’t respect postpartum women and give them the space and freedom to be in whatever body size they need to be. We have to create space ourselves for this. We have to swim against the cultural current. The postpartum period is so vulnerable. So many things feel out of control (hello sleep deprivation and a crying baby and ALL the life changes) that it makes sense that many women turn to food and exercise to gain some sense of control. And with the pressure to get your body back (whatever that even means, you never lost your body) it’s no surprise that many women find themselves pursuing weight loss.
Ignoring hunger cues and restricting calories can be quite harmful. We often hear, “your body needs 500 additional calories during breastfeeding” but really, that is such a generalized statement. It has some validity – it’s based on the assumption that breastmilk contains about 65-67 calories per 100 mL or about 20 calories per ounce. And it’s based on the assumption that most exclusively breastfeeding moms produce around 25 ounces of breastmilk per day if feeding on demand. But there is so much fluctuation from mom to mom.
The amount of calories you need while breastfeeding will be dependent on several factors:
Basal metabolic rate (BMR)
This is how many calories you burn at rest, which depends mostly on your body weight, height, age and gender. Genetics can play a role here too.
Physical activity level (PAL)
This is how much you move throughout the day, which includes your daily life, not just structured exercise or daily walking. It’s cleaning and showering and cooking and all those things …with a toddler, my PAL is much higher than it used to be when I sat working mosts of the day.
If you’re exclusively breastfeeding – meaning baby only gets breastmilk and no formula or solid foods, this is around 25 oz/day, but it can range from anywhere between 19 to 30 oz/day depending on your baby – if your baby eats some formula and/or solid foods they probably take in less than this, but not significantly less.
If you’re exclusively breastfeeding plus pumping 1 or more times a day to build up a freezer stash or donate milk you’ll be making more milk than just what your baby drinks which means more energy your body expends. If you’re exclusively pumping it will be easily to know your milk output per day – I know some moms who could produce 60-70+ ounces of milk per day when exclusively pumping – that’s 1200 to 1400 calories of milk production alone! Equate that to running a half marathon every day.
The couple of times I traveled for a day or two and exclusively pumped for Cal during his first year, I’d pump around 35 ounces/day – that energy demand is going to be higher than days where I just exclusively breastfed him.
Energy needed for the metabolic process of milk production
This is around 20% of the energy produced since our bodies are around 80% (literature states up to 90ish%) efficient at producing breastmilk. So if you make 25 ounces of milk per day that is ~500 calories of energy in the milk alone (25 x 20 cals/ounce = 500) and 20% of 500 is 100. Therefore if you produce 25 ounces/day of breastmilk your body would need an additional 600 calories on top of the energy needed to support your BMR and PAL.
To put this in real life perspective, Cal was exclusively breastfed up until six months when we introduced solids. So let’s say he ate the average of 25 oz/day. I pumped 1-2x a day in addition to his feeds to build up a stash and provide milk for an adopted baby at our church. My pumping output was anywhere from 7 to 11 oz most days. So between breastfeeding and pumping I was probably making 32 to 36 oz of milk per day. So 34 ounces on average. That’s 680 calories right there. And 20% of 680 (for the metabolic process) is 136. Add 680 to 136 and you get 816 calories. That’s 60% higher than the catch all 500 calorie recommendation!
I know I’m getting nitty gritty and science-y, but I point all this out because for a lot of women, that 500 calorie recommendation is actually too low. Moreover, because we live in a diet ridden culture, most women don’t have an adequate picture of what normal eating looks when not pregnant of breastfeeding. As a whole, we underestimate how much food our body’s actually need on a daily basis. Couple that with an inaccurate perception of increased energy needs during lactation and it’s easy to see how a new mom could be consciously or subconsciously not meeting her energy needs.
To simplify, think of breastfeeding as, on average, running 6ish miles a day. That’s a lot of daily energy output on top of your normal life! NO WONDER you feel intense hunger postpartum and throughout breastfeeding. I can remember feeling like a bottomless pit most days. I could eat anything and everything and never feel overly full. If you’ve struggled or are strugglin with disordered eating or an eating disorder in the past, this increased hunger can be very challenging to navigate. You are not alone, I assure you. Get the support you need and deserve to care for you physical and mental health. Whether that’s from an RD, a therapist, both or a supportive partner or friend. You need cared for too, not just baby.
Most importantly, don’t get caught up in the numbers I’ve provided here. The point of me spelling out this in so many numbers is to give you perspective. And to empower you with some knowledge of why you’re so dang hungry. If you’re an intuitive eater, follow your hunger cues. They will lead you. I have many mamas who message me saying, “but I am eating more than my husband!” and that is normal. Even if you’re not breastfeeding that is normal. Your hunger can be trusted. Biology is trustworthy. That person’s opinion or what you read on the internet is not always trustworthy.
**I won’t go into hydration here for brevity’s sake, but know that drinking to thirst and having water on hand will usually ensure adequate hydration. A good sign of hydration is pale yellow urine. Note that drinking excessive water (urine is totally clear) does not increase milk production.
When I searched the literature, I couldn’t find anything conclusive on exercise itself impacting breast milk production. From the research we do have, moderate intensity exercise doesn’t seem to effect breast milk production, quality, etc. High intensity exercise (meaning you’re out of breath and cannot talk) does cause lactic acid level to increase in the short term, but there is no known harmful effects on baby. So although exercise itself doesn’t seem to significantly effect breast milk quantity or quality, if you’re unable to nourish your body adequately to cover the energy expenditure from exercise that is when you will see a drop in milk supply due to insufficient energy intake. Especially if you ramp up exercise quickly and aren’t eating enough, your body will experience a more sudden drop in energy availability which impacts milk supply more. Go slow. Listen to your body. Do what feels good physically and mentally (and that might be nothing at all!) and be mindful of nutrition.
Anecdotally, I found that when I exercised and then nursed right after – which was usually after a long bike ride since I would always nurse before exercise to make my boobs lighter – I found that my let-down was much slower. It was back to normal by the next feed, but short term, something had to be going on. Even though my bike rides were low intensity, perhaps there was still cortisol production in my body that inhibited my let-down reflex? Just some thoughts! Even if the exercise feels good mentally and physically, if you notice that when you do certain exercises or a certain duration or frequency of exercise your supply drops – make sure you’re meeting your nutrition needs and/or ease up on the physical activity.
Breast storage capacity varies from woman to woman. Some women have a smaller storage capacity and some women can store a whole lot of ounces of milk in their breasts at once. Whether you have a small or large capacity doesn’t affect your ability to produce enough milk for your baby. If you have a smaller capacity, baby will likely nurse more often to get the amount of milk he needs over 24 hours. Breastfeeding is supply and demand. Empty boobs produce milk much faster than full boobs. So the more often your boobs are emptied of milk, the quicker they will fill with more milk.
If you are trying to feed your baby based on a schedule vs on demand that can affect milk supply. Your baby knows how often to nurse (aka how often to empty your boobs) so your body can make sufficient amounts of milk. But if you’re someone with a small storage capacity and feeding on a schedule, your boobs might not be emptied frequently enough to make adequate amounts of milk. So in short, feeding on demand is really important (especially in the early days!) for establishing and maintaining adequate milk supply.
It was so helpful for me to learn that my pumping output wasn’t an accurate reflection of my milk supply. A baby is far more efficient at extracting milk from your boobs than a pump – you’ve also got more oxytocin flowing (which makes the milk come out) when you nurse your baby vs pump. You could pump 1 oz in a 30 minute pumping session, but your baby could suck out 4 oz in a 10 minute nursing session. So don’t let your pumping output get you down – especially if you don’t pump that frequently! The more often you pump, the more used to the pump your boobs get and you will likely (but not always) see an increase in output – as long as you stay as relaxed as possible while pumping. Look at pictures of baby and don’t look at how much milk is coming out.
Most importantly though, if you feed your baby a bottle (or someone else does) you have to replace those ounces of milk in the bottle with a pumping session because of supply and demand. If you don’t pump out those ounces to replace the feed, your body doesn’t know your baby ate those ounces and therefore doesn’t know to make more milk.
Sleep & Stress
I found “sleep when the baby sleeps” to be such unrealistic advice. But I tried as much as I could. Lack of sleep can affect milk supply due to increased cortisol levels. Now, our bodies are quite resilient in that biologically they are prepared for broken sleep (you have a baby after all who needs you often) but even if sleep is broken, try to get as many night time hours and naps as you can given your situation. Easier said than done!
Stress hormones (cortisol, adrenaline and norepinephrine) can inhibit your let-down reflex. And if your let-down is inhibited or blocked, it’s very hard to get the milk out of your boobs which would then decrease the amount of milk baby is eating or how much you pump. The less milk that comes out, the less milk your body will make. I remember when Cal was around 8 months he went on a nursing strike after I let out a loud yell when he bit me while nursing. I became incredibly stressed about him not nursing. Looking back, I’m now so glad I have that experience in my back packet for the future since I know it will pass with time and different techniques. But I was so stressed for those 24 hours and literally no matter how much I pumped, NOTHING came out…because I was so stressed. My milk supply felt shot. I shared that experience and what worked to get him back on the boob in my IG highlights if that sounds helpful for you.
So in short, care for yourself the best you can. Breastfeeding can be so hard and stressful. Your mental health matters. Seek the support you need. Ask for help around the house. And remember, if your mental health is really taking a toll due to breastfeeding, I believe your baby needs you to be emotionally present, attached and well more than they need breastmilk. Give yourself grace.
Support & Access to Information
I think women don’t get nearly the amount of support they need to have a successful, positive breastfeeding journey. There are ups and downs and challenges and without people standing in your corner championing you and telling you, “no, you CAN do this”, it’s really hard to keep going in the face of difficulty. If a mama is struggling and someone she trusts says, “just supplement with formula” instead of really supporting her with resources and referrals and coming alongside her that makes it really hard to continue on with breastfeeding. Formula, certainly has a time and a place – but we need more support as moms! Here are a few resources I’ve found incredibly helpful and recommend to patients, clients and friends.
LLL – their books are great, especially The Womanly Art of Breastfeeding
A supportive pediatrician (I think a doc who is in line with the WHO recommendations can make such a difference!)
Legendary Milk on IG
IBCLCs – you can search for ones in your area here
Brown, A., & Arnott, B. (2014). Breastfeeding Duration and Early Parenting Behaviour: The Importance of an Infant-Led, Responsive Style. PLoS ONE, 9(2). doi: 10.1371/journal.pone.0083893
Kominiarek, M. A., & Rajan, P. (2016). Nutrition Recommendations in Pregnancy and Lactation. The Medical clinics of North America, 100(6), 1199–1215. https://doi.org/10.1016/j.mcna.2016.06.004
Megan A McCrory, Laurie A Nommsen-Rivers, Paul A Molé, Bo Lönnerdal, Kathryn G Dewey, Randomized trial of the short-term effects of dieting compared with dieting plus aerobic exercise on lactation performance, The American Journal of Clinical Nutrition, Volume 69, Issue 5, May 1999, Pages 959–967, https://doi.org/10.1093/ajcn/69.5.959
Rosenberg, K. (1994). A randomized study of the effects of aerobic exercise by lactating women on breast-milk volume and composition Dewey KG, Lovelady CA, Nommsen-Rivers MS, McCrory MS, Lonnerdal B N Engl J Med 1994;330:449-53. Journal of Nurse-Midwifery, 39(3), 169–170. doi: 10.1016/0091-2182(94)90104-x
Tiedje, L. B. (2000). The Effect of Weight Loss in Overweight, Lactating Women on the Growth of Their Infants. MCN, The American Journal of Maternal/Child Nursing, 25(4), 222. doi: 10.1097/00005721-200007000-00018
Maggie Getz says
Thank you for this post, Robyn! I’m still nursing my almost 14-month-old, and I’m so thankful to have been able to nurse him this whole time. He never took a bottle, which used to stress me out but now I feel completely at peace with it! I agree we need better information on breastfeeding, especially in our diet-obsessed culture. Thank you for paving the way!
Also that last pic of Cal is just too cute 🙂
Great post; just wanted to note that you have an error in your math for the energy required to produce milk. It looks like you did 20% instead of 80%; 80% of 500 is 400, not 100. And 80% of 680 is 549, not 136. So if the energy required to produce the milk is 80% of the caloric yield of the milk, the mom’s energy needs are significantly higher than the catchall 500/day especially for moms producing these very high milk volumes.
Hi Beth – the math is right. It’s a bit confusing to understand – I’ll go back and reword it better to clarify. Breastmilk production has an 80-90% efficiency range – meaning our bodies can produce 80-90% of it without expending extra energy. So you’re multiplying the energy cost of the milk itself (the 500 cals) by 20% or 0.2
Hope that makes sense!
Thanks for your reply! That sounds quite different than the original wording and makes much more sense with the math as you provided in the original post. Thanks for updating. Which of your references provided the info on 80-90% efficiency range? (I have had a hard time finding a professional reference for this information despite intuitively knowing that if an individual is producing X calories worth of milk, that individual must be expending X+ some unknown amount to produce so this reference would be super helpful to have). Thanks again.
I realized I wrote it as 80% vs 20% even though the math was 20% which would make that confusing! The Handbook of Nutrition & Diet has this information in it – it’s info I’ve known so I probably didn’t reference it (I wish I had that kind of time of my hands to reference every source I’ve read!)
Thanks so much for sharing! I’m 13 days out from my due date as a first time mom and this was very helpful on what to expect. Especially understanding that I won’t get the same volume from pumping vs a baby feeding. Can’t wait to read part two.
Congrats to you Tricia!
This was such an excellent read. I have had two very different breastfeeding experiences with both of my children, so I just wanted to point out that breastfeeding can be a completely different experience from baby to baby. With my first I had some PPD going on and baby had a tongue tie (which we didn’t realize until six weeks in). I exclusively pumped for nine months and it was rough. SO many people started to tell me that I looked so happy/better rested/like a happier mom once I stopped pumping. I truly didn’t realize how much it was wearing me down mentally and emotionally. Before my second was born, my husband and I had a long honest talk and we realized I couldn’t put myself though that again (especially with a two year old running around). We decided I’d try nursing with the new baby, take advantage of the six free visits with a lactation consultant that our insurance provided, and find a nursing support group. If nursing wasn’t working a couple months in, I’d switch to formula guilt free. My second baby nursed like a dream right from minute one. It was the most intuitive experience of my life. I’m fifteen weeks with my third and realizing early this time that all I can do is the best I can do and my babies love me regardless.
Thank you so much for sharing Meg – YES every experience is so so different. I am so much respect for you for pushing through 9 months of EPing. Wow. And I respect you for knowing your limits in order to care for your mental health. If you aren’t in a good place, something’s gotta change. Our children’s love is certainly not dependent on if we BF or not. Love to you!
Loved this so much, thanks for sharing! I am due with my first in September in Boston – did you have a pediatrician in Boston who was supportive of your breast feeding goals that you’d recommend?
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So so helpful! I’m trying to learn a bit about breastfeeding as I am due with my first baby in October. As always I love your approach to wellness, intuitive eating, motherhood, etc so thank you 🙂
Thanks so much for this. As a mom in the postpartum period with her second child, it’s still so helpful to hear about how gentle we need to be with our bodies during this time. I was thinking the other day about how much pressure is put on moms to lose weight fast and how we’re made to feel lazy and as if we “let ourselves go” if we don’t start restricting and exercising right after baby. Postpartum is hard without all of that. I feel that breastfeeding, although such a wonderful thing for me and my babies, takes a toll as does caring for a newborn and getting less sleep than our bodies are used to. It’s hard and we need to be more gentle with ourselves. I think there’s a lot to be said for eating a lot of good food, practicing gentle, enjoyable movement, and resting as much as needed (or as much as is possible) during this time.
Hi from Quebec city, Canada! We are lucky to have access to a great maternity leave programm. The longest you can take is 50 weeks with a salary (a % from your salary). It helps a lot for breastfeeding!
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