Fat in Breast Milk and How It Supports Your Baby’s Growth
Published Date:June 3, 2025
By Ali Weatherford
Eating high fat foods is not such a no-no anymore, and for our babies, it’s always been an especially good thing! There are definitely some fats that are not good for you, but the fat in breast milk is very healthy and a very important component of your baby’s primary food source. They need it!
How Much Fat Is in Breast Milk?
Human milk is similar in fat content to whole milk. It ranges from 3-5%. Whole cow’s milk is often 4% milkfat. If you pump breast milk into bottles, it will separate over time and you can really see the amount of fat in the milk. The fat or “cream” rises to the top, and it can be a pretty thick layer!
Is Fat Content Always the Same?
Some people have milk with a higher fat content than others. Babies get about 50% of their calories from the fat in the milk. So, if you have milk with a higher fat content, your baby will need less milk to get full and grow. If you have lower fat milk, your baby will need to drink more to get the same number of calories. That’s totally normal! We’re all a little different.
It’s also true that milk has more or less fat depending on how long a baby feeds. The milk that comes out first is called foremilk. That tends to be lower in fat then the hindmilk, which comes out more toward the end of a feeding. All the milk is nutritious, important, and has the same components, but just in different proportions. The hindmilk is usually fattier. So, if a baby feeds for a short amount of time, they may not get as much of the hindmilk.
Breast milk also changes throughout the day. It tends to be higher in fat in the evening and overnight. So, since the fat content of milk is not perfectly stable, it’s important to feed babies on demand so they get all of the important fats that they need to grow and develop. On-demand feeding is recommended over scheduled feedings. When a baby is allowed to breastfeed whenever they request it, and are allowed to stay at the breast as long as they want, they are more likely to get the full volume of fatty milk so they feel satisfied for longer and have everything they need to grow and stay healthy.
Why is Fat in Breast Milk Important?
Fats might be the most important nutritional component of breast milk, although it’s so hard to choose just one! There are nutritional components of breast milk, and there are also other components of breast milk that are less about nutrition, and more about immune function and organ development. When the nutritional components are discussed, people are referring to fats, proteins, and carbohydrates. These are the things that give a baby energy and help them grow. Fat supplies the most energy to the baby. It also gives the milk great flavor and aroma, making it more appealing to drink. Also, some of the fatty acids in milk contribute to the baby’s growth, immune function, vision, cognitive and motor development.
Can You Change the Fat Content of Breast Milk?
If you’re worried that your breast milk is too fatty, don’t! It most likely just means that your baby will be satisfied with a smaller amount of milk. You don’t need to try to change it, even if you have a family member telling you that too much fat is bad for your baby. If you’re worried that your milk is not fatty enough, also don’t worry! Just be sure to let your baby nurse as long as they need to and as often as they want. It might take your baby a little longer to get the calories they need, but they can still get there. A baby’s weight gain is not dependent on the fat content of the milk. The only thing that affects that is the volume of milk the baby gets overall. When a baby is getting enough milk, whether that’s high fat milk or low fat milk, they gain weight.
If you’re eating a low fat diet or a diet that is deficient in nutrition, your body will try to compensate by using your maternal fat stores. Your milk will continue to contain the nutritional components that your baby needs, including fats.
If you’re eating a well-balanced diet, your breast milk will contain a higher percentage of nutritional components from the food you’re eating. What you eat does not really have an impact on the amount of fat in your milk, but can affect the types of fats in your breast milk. We know that there are certain fats that are extremely healthy and vital for growth and development like Omega-3 fatty acids (DPA, DHA) and unsaturated fats. It’s a great idea to eat lots of these.
You’ve probably heard of the different health benefits or drawbacks depending on the type of fat. If you eat a lot of partially hydrogenated fats and oils or trans fats (fully hydrogenated oils do not contain trans fats), your milk will contain more of those fats. We know that those types of fat can actually be harmful, so it’s best to avoid or reduce them. They do transfer into your breast milk. Eating plenty of unsaturated fats is good, and a moderate amount of saturated fat is OK too, but no trans fats are healthy. These are fats found in highly processed foods like margarine, shortening, packaged cakes, pies, chips, and many deep-fried foods.
Also, if you lose a lot of weight while breastfeeding, your milk can actually be higher in trans fats which are being removed from your body due to the weight loss. More of those fats will appear in breast milk.
So you can’t really change the amount of fat in your breast milk by eating differently, but you can change the types of fats that show up in the milk. Avoiding those partially hydrogenated oils is a very good idea while you’re breastfeeding, so your baby gets the very best fat you can give them. There are so many healthy AND fatty foods that are delicious and easy to add to your diet. Nuts, avocados, salmon, and olive oil are examples of healthy fats that are at the top of the “good” list. Who doesn’t want to eat more guacamole?!
References:
Fats: The good, the bad and the ugly
The composition of human milk – PubMed
Impact of Maternal Diet on Human Milk Composition
What affects the amount of fat or calories in mom’s milk? – KellyMom.com
The physiological basis of breastfeeding
Human Milk Lipid Profiles around the World: A Systematic Review and Meta-Analysis – ScienceDirect
6 Milk Composition | Nutrition During Lactation | The National Academies Press (page 123)
