What You Need to Know About How Many Calories Are in Breast Milk

Published by 
Jess Miller
Last updated: 
March 21, 2023
Mother with cute daughter. Mom breastfeeding her little daughter

With all of the debate around breastfeeding in public, it can be easy to forget why breast milk is so important in the first place. That is, it provides irreplaceable sustenance for babies as they grow from newborns into people of their own. But when thinking of breast milk as a food, another question arises: How many calories are in breast milk?

While breast milk might not come in a box with a list of nutrition facts on the side (formula excluded), it's just as much a food as anything you or I eat as adults.

So, what makes up breast milk as a whole, making it so incredibly nutritious for growing infants? And, at the end of the day, how many calories are in breast milk, anyway?

How Many Calories Are in Breast Milk?

Let's start with the most straightforward question: How many calories are in breast milk?

On average, there are 171 calories in one cup of breast milk. However, that's where the straightforwardness ends, unfortunately.

You see, unlike our commercially produced foods, breast milk isn't uniform from one woman to another. Actually, one woman's breast milk can change drastically in composition within a matter of hours.

What causes these changes?

Everything from your activity level and nutrition to your emotional stress can play a role in how many calories are in your breast milk. But that's only the start.

It's Not Just About the Calories

Baby Milk's Time
Image source: freepik

Yes, calories tell us how much basic nutrition is contained in breast milk. Without these calories, our children wouldn't have the energy needed to grow from a newborn to a toddler.

Once you get past this number, though, there's much more to breast milk than just the amount of calories. In fact, calories might be one of the least important nutrition facts when it comes to the near-magical properties of breast milk.

Count your macros

If you practice healthy eating, then you're probably at least somewhat familiar with the concept of macronutrients.

Essentially, macronutrients, or "macros," are the basic building blocks of energy and food as a whole. There are three types of macronutrients: Carbohydrates, fats, and proteins.

While each macronutrient plays an extremely intricate role in the human body (young or old), they do have some generalized functions.


Carbs are responsible for providing easily accessible energy. With that said, they're also the main source of calories in pretty much any food.

As with any type of milk, the most common carbohydrate in human breast milk is lactose. Unlike many adults, though, lactose doesn't pose a digestive problem for babies.

As babies, our bodies are perfectly equipped to process lactose and break it down without issue. In fact, lactose plays a crucial role in the gut health of breastfeeding children.

Lactose fights the growth of dangerous bacteria in the stomach while also aiding in the absorption of other key vitamins and minerals. Without this key substance, the answer to, "How many calories are in breast milk?" really wouldn't matter much.

Building blocks

Whether you're a professional athlete or an average Joan, proteins are the core building blocks to almost every part of the human body. Without adequate protein, our bodies are incapable of building muscle, balancing hormones, and maintaining a healthy brain.

And that's true for both you and your baby.

In human breast milk, the two main types of protein are called whey and casein. These proteins are present in all milk, including dairy from cows. However, human breast milk offers a unique ratio of these two compounds that is especially easy for babies to digest.

One of the main arguments against feeding formula unnecessarily is that the balance of protein is off. While human breast milk contains up to 80 percent whey, many formula recipes rely more on casein.

Yes, your baby will still get plenty of protein. But the higher ratio of casein can make the formula much harder for them to digest properly.

So, when asking, "How many calories are in breast milk?", you should also be asking, "What type of protein is in breast milk?"

The incredible power of protein

When it comes to breast milk and your baby, protein does even more than just provide the building blocks for healthy growth! Actually, there are several incredible benefits unique to the protein found in human breast milk:

  • Prevents the growth of harmful gut bacteria
  • Improves iron absorption
  • Protects against infections like E. Coli and Salmonella
  • May help prevent allergies later in life

Healthy fats

In the world of adult nutrition, our relationship with fat is a complicated thing. But while healthy fats are crucial for adults, they're absolutely necessary for healthy infant development.

One of the most important functions of fat in breast milk is to promote healthy brain development in nursing babies. Without these essential fats, young children also aren't able to properly absorb vitamins and nutrients present in their mother's milk.

Getting into the nitty-gritty details

Speaking of vitamins and minerals, the nutrition found in human breast milk goes much further than just calories, carbohydrates, proteins, and fats. After all, breast milk is responsible for all of your baby's nutritional needs until they are weaned.

With that said, however, remember that the mother's body doesn't just magically produce these vitamins and minerals out of thin air. Instead, you should consider boosting your intake for certain nutrients or even giving supplements directly to your child, including:



Iodine plays an important role in hormone regulation and is one of the key nutrients passed from mother to infant through breast milk.

Fortunately, it's easy for mothers to boost the iodine content of their breast milk by taking supplements or consuming more iodine-containing foods.


NovaFerrum Pediatric Drops Liquid Iron Supplement for Infants and Toddlers

According to the CDC, even mothers who get plenty of iron in their own diets will need to supplement their infant's diet with additional iron.

Because most formulas are supplemented with additional iron, feeding both breast milk and formula to your child can help lessen their need for additional iron. However, they are still unlikely to get enough iron even from a diet of both breast milk and formula.


There are countless essential vitamins in the human body. However, the most important ones found in breast milk include B12 and D.

Many people lack enough B12 in their diets. So, it's especially important for nursing mothers to monitor their diet and vitamin intake. While severe cases of vitamin B12 deficiency in infants aren't extremely common, they can result in side effects like anemia, skin and hair conditions, and developmental delay.

Nature's Bounty B-12 5000 mcg Sublingual Liquid Energy Health

Mothers who avoid animal products are at the highest risk for vitamin B12 deficiency, both for themselves and in their breast milk. Along with upping your intake of B12-rich foods, supplements are also a viable option.

Ddrops Baby 400 IU Drops

Since vitamin D plays such a central role in bone development, it's easy to see why infants are at such high risk for deficiency. Even mothers who get plenty of vitamin D in their own diet and pass that nutrition on through their breast milk are often encouraged to administer supplemental drops directly to their infant.

Of course, always consult with your doctor before adding new supplements to your diet or making any other major changes as you breastfeed.

Getting the Most from Your Own Breast Milk

Breask Feeding 1
Image source: freepik

Many nursing mothers choose to pump and store their breast milk for cases when they aren't around or just don't have the chance to stop and breastfeed.

However, proper storage techniques are necessary to prevent your breast milk's nutritional content from dropping and to keep the milk from going bad altogether.

Along with sterile pumping and transferring, using the best breast milk storage bags will help you stay organized and ensure your baby gets the most from every meal. Plus, knowing you have healthy breast milk ready to go at a moment's notice is sure to take a load off your mind, too.

Meeting Baby's Nutritional Needs Every Day

So, at the end of the day, maybe its not the answer to, "How many calories are in breast milk?" that really matters. Instead, a deeper look is needed to truly understand and appreciate everything breast milk has to offer.

Whether you opt to exclusively breastfeed, supplement with formula, or stick with formula entirely, all that matters is your baby's health.


Breast Feeding
Image source: freepik

Are you surprised by the answer to, "How many calories are in breast milk?" Were you expecting it to be more or less? Let us know your thoughts in the comments below!

Featured image source: freepik

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