How Many Calories in Breast Milk? What You Need to Know as a Mother

How Many Calories in Breast Milk? What You Need to Know as a Mother

On average, your baby gets 154 calories in 8 ounces of breast milk. Two large eggs are about 156 calories and a medium-sized apple is 95. Eight ounces is the size of most pumping bottles. 

But exactly what is in these calories in breast milk? And how many calories of breast milk does your baby need a day to be healthy and strong? And how do you make sure you're producing enough breast milk and that it has all the right nutrients? 

It's a lot to think about, especially with a new-mom foggy brain, so we've put together the basics on breast milk for breastfeeding mothers to simplify and demystify breast milk's caloric and nutritional makeup.


Your mama body is built to perfection to make milk that gives your baby everything she or he needs at each stage of growth: a complete source of nutrients and immune-boosting antibodies.  

The nutrients and calories in breast milk are made up of water, protein, fat, and lactose. The more fat your breast milk has, the higher the calories.

But the exact makeup of these nutrients in your milk is hard to pin down because it varies. Breast milk composition changes in time as your baby grows, changing quickly in the first few weeks of your baby's life and then more slowly when the “mature” breast milk comes in at three weeks. 

Breast milk composition also changes during each feeding session. For example, when you start nursing, it's lower in fat, and at the end of feeding, the “hindmilk” comes in which contains more fat. 

Composition of your breast milk also changes throughout the day. The milk you produce in the morning is different from milk produced at night. Breast milk composition is also different between women and is affected by weight, menstruation, body mass index, and how often you breastfeed.

Let's take a closer look.

Breast Milk Composition

The exact makeup of your breast milk is dynamic but, in general, here is the breakdown: 

  • 1% of breast milk is protein
  • 3.8% of breast milk is fat
  • 7% of breast milk is lactose
  • 87% of breast milk is water

Breast milk also contains calcium, phosphorus, magnesium, the B vitamins, and vitamins C, A, K, D, and E. It contains zinc, iodine, copper, iron, nicotinic acid, pantothenic acid, hormones, growth factors and more.

Right after birth, breast milk also contains the magical, immune-boosting colostrum. It's lower in fat and carbs than mature milk so it's lower in calories too, but it does contain 10 times more beta carotene as well as more zinc and vitamin E. After the first week, there's a decrease in protein, vitamins, and minerals in breast milk.

Fat and lactose are the heavy hitters when it comes to calories. About 50 to 65% of calories in breast milk come from the fat and about 35% to 45% from the lactose.


Fat may only make up a small part of your breast milk but it accounts for most of the calories. It also plays a powerful role in your baby's health. 

Fat helps your baby's body grow and use the vitamins it gets. Fat also helps develop your baby's brain. The key players here are cholesterol and fatty acids called DHA, which is a “long-chain polyunsaturated fatty acid” (LCP) called “docosahexaenoic acid.”  DHA and cholesterol help build the “myelin” that coats neurons and is needed for them to send messages. In other words, fat helps your baby think faster and build neuron functioning.

This is true for adults too! We all need our fat.

As we said earlier, fat content in breast milk, and therefore calorie count, is dynamic. For exact numbers, you'd need a centrifuge, but here's a fun experiment to compare how much fat is in your milk at different times. You can only do this if you have a breast pump. 

But just for fun:

  • Pump milk  
  • Place in a clear bottle and cool for 12 to 24 hours
  • Measure the amount of cream (fat) that rose to the top
  • Repeat at a different time and compare the height of the cream


There are two kinds of protein in breast milk: wheys and caseins. Wheys are liquid and easier to digest, while caseins curd in the stomach.

Proteins help baby build muscle and bone. They also help defend the body against unhealthy invaders. For example, proteins have “antimicrobial” factors immunoglobin A (IgA) to protect baby's intestines and lungs against viruses, parasites, and bacteria.

High-Quality Breast Milk

Generally, your body makes exactly what your baby needs unless you're malnourished. The composition is ideal. The question to ask is: Is your baby getting enough of this good stuff? But we'll get to that later.

Now, let's touch on three ways to improve your breast milk composition for fat, protein, and vitamins. 

One way to improve the quality of breast milk is to boost the good fats in your diet. Breast milk in the U.S. has some of the lowest DHA levels in the world. High levels occur in countries where they eat a lot of fish because it contains those good fatty acids. You can eat foods high in omegas or take plant-based supplements. Nuts and seeds are great too.

Another way to make sure you're producing high-quality breast milk is to eat a high-protein diet. Third, you can make sure to take the prenatal vitamins during your pregnancy.

What's Good for Baby

Your body makes what baby needs and baby, by instinct, knows when and how to get it, ensuring healthy growth. Babies need different amounts of calories at different stages and your milk adapts to the different nutritional needs. 

Scientists have calculated the average amounts of calories babies need. For example, they came up with a formula based on age that you can use (or keep reading for easier tricks).

For infants zero to three months, add 175 to (weight in kg x 89 - 100) for the average calories per day. For babies four to six months, add 56 to (weight in kg x 89 - 100).

At six months, solids are usually introduced (but not always necessary) and calories per day go up to 682, with 486 from milk and 196 from food. As the baby gets older and eats more solids, breast milk calories go down while solid food calories go up.

But this doesn't really help you figure out if your baby is getting enough milk, does it?

The good news is that you don't need to measure. You can tell by the following signs that mean your baby is getting enough breast milk

A Few Signs Baby Is Getting Enough Milk Calories

Chances are you're producing enough milk for baby, and baby is drinking what he or she needs but there are some easy ways to tell if baby is getting enough milk.

Check in with your doctor. Weigh in as advised by your pediatrician, especially in the beginning to check infant feeding and growth. Up until three months of age, babies typically gain an ounce a day. Know that babies that are breastfed tend to gain more weight faster than formula-fed babies at first but then later formula-fed babies gain weight faster.

Other signs your baby is getting enough breast milk:

  • Your breasts are softer after your baby feeds
  • Your baby falls asleep and seems happy after eating
  • Your baby's pee is light or clear yellow (not dark yellow/orange)
  • Your baby poops regularly
  • Your baby alternates between short naps and being alert rather than sleeping for long periods (babies nurse often!)

Also, if your baby uses the “open mouth wide – pause – close mouth” ideal suckle and doesn't linger or use your breast as a pacifier, chances are she or he is getting enough milk. The pacifier suckle is rapid because baby isn't fully latched on and getting the milk needed.

Easy Tricks to Increase Your Milk Supply/Calories if Needed

If the signs say your baby isn't getting enough milk, there are a few tricks you can try to increase your milk production. 

Stay healthy yourself! Eat well, exercise, get enough sleep. Try side-lying nursing to sleep while baby eats!

Keep your blood sugar up. This will help you manage infant feeding and everything else in your life with a clear head and energy. Snack regularly on omega-3-rich snacks that include easy-to-digest proteins like flax seeds, nuts, and oats. Keep that baby bag well-stocked.

Drink water. You need water to make milk. It's a direct correlation.

Eat herbs and other galactagogues. Blessed thistle and fenugreek are herbs that increase milk supply. Other galactagogue milk boosters include walnuts, almonds, rolled oats, flax seeds, and brewers yeast.

Nurse more. The more you breastfeed or pump, the more milk your body makes. Pump when you're away from the baby. Instead of letting baby sleep through the night, try the side-lying position to get an extra feeding in and still get your rest.

Cuddle. When you're near your baby, your body is inspired to make more milk. Mother Nature has your back!

Yes, Mother Nature Has Your Back

At 12 to 18 weeks pregnant, your body is already producing colostrum and you are giving baby the calories needed to grow into a healthy infant.

Once breastfeeding, you and baby start a relationship of encouragement and love. You work together in partnership and if you pay attention to the natural signs, make the small adjusts to calories in breast milk if needed, and keep yourself energized and healthy, baby can grow and thrive. In tandem, the two of you are perfect.

At Nourisher, we are here to encourage you and baby on your breastfeeding journey. If you feel like you're not making enough milk, check out our post for breastfeeding mothers with 5 easy tips to increase your milk supply and try a box of our lactation bars.

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