There aren’t two types of milk in your breasts. There isn’t low-fat milk and high-fat milk, good milk and bad milk, thin milk and thick milk. There is just breastmilk.

Do you know how they make skim milk?

Probably not, because very few of us have ever seen raw or unhomogenized milk. When you milk a cow, the milk comes out warm and fluid into the bucket. The milk is chilled and the fattier milk rises to the top. Then, whoever is processing the milk “skims” the fat off the top. What is left is a low-fat or no-fat version of milk. Get it? Skim milk? If you have pumped and put your milk in the fridge, you have noticed the same phenomenon. As the milk cools, the fattier, more opaque milk rises to the top and the bottom portion of the milk appears thinner, more translucent. Perhaps you would call this milk more “watery.” But, it isn’t watery. It doesn’t lack nutrients. It is just lower in fat.

Breastfeeding moms read a lot about foremilk and hindmilk and, for lack of a better term, obsess about it. 

We don’t know the fat concentration of your milk when the baby first starts nursing, nor do we know the rate at which the milk gets fattier. You may have read or been told that you must nurse for at least 15 minutes for the baby to get the “good milk” a.k.a. “the hindmilk.” Not true. Some babies get it immediately, for some babies it takes 45 minutes. This depends on your milk supply, the time of day, and the last time you expressed milk. 

What we do know is that something triggers a baby to release the breast when they have had enough fatty milk. That is why it isn’t a good idea to time a baby’s feeding and pop him off at some set arbitrary time. It is also why you shouldn’t keep putting baby back on the same boob to “empty it” even if he is popping off. If he seems done with the first boob, whether it has been 10 minutes or 45 minutes, by all means, offer the second one! 

What we also know is that the hindmilk takes longer to get out of the boob than the foremilk because it is thicker. Like a milkshake takes longer to pour than a glass of milk. So, yes, technically the baby gets the milk that flows out easier first. But, it isn’t like skim milk, skim milk, skim milk, half-and-half.  It is more like skim milk, 1%, 2%, whole milk, half-and-half–meaning that the milk gets progressively fattier as the feeding goes on. 

This also explains why your baby camps out on the boob all evening long and cluster feeds. In the evening time, you may have noticed that your breasts feel less full. Many women tell me they “have nothing left” in the evening. Not true. Your boobs have milk, but it is mostly that thick fatty milk. So, baby needs to suck extra long to work that thick yumminess down to his mouth. Since it is lower in volume and takes longer to get out, he is there longer (and often falls asleep from all that effort). But, your reward is that a belly full of fatty milk yields a nice chunk of sleep for baby (and hopefully for you as well). 

Foremilk/Hindmilk Imbalance

  • Sometimes babies get too much foremilk and not enough hindmilk if the milk supply they are nursing from is being controlled by someone other than them. Ie, a milk supply mostly managed with a pump and sometimes offered to a baby for nursing.
  • If you most often pump the breast you are offering the baby and you most often pump a lot more volume from that one breast than the baby eats in a bottle, there is a chance the baby may get full on foremilk before being able to access the hind milk.
  • There are a few ways to handle this scenario, depending on your long term feeding and supply goals. In the moment, if you are suspicious that the breast you are hoping to offer the baby to nurse from has a disproportionate amount of foremilk in it, remove an ounce or two with a haakaa or pump before latching the baby. In the long term, if you are hoping for more balanced nursing sessions, consider down regulating your milk supply