There is a lot of confusion and poor breastfeeding advice arising from the idea that there are two sorts of breast milk—namely foremilk (watery, low calorie) and hindmilk (high fat, high calorie). And, depending where you live, the confusion may go one step further, you may hear about three kinds of milk; watery soup, dinner and pudding.
All breast milk is good
As a result of not understanding that all breast milk is good, and not really understanding how breastfeeding works, mothers are being told to stay on one breast per feed or feed from one breast for random blocks of time to “get to the hindmilk”. After all, the watery soup is no more than water and without that fatty pudding a baby can’t gain weight, right? Wrong. Even if that was right, why stop short of offering the “three course meal” from the second breast? Especially if a baby is having trouble gaining weight.
This article looks at how babies grow, how breastfeeding works, the facts about foremilk and hindmilk, and how staying on one breast to get to the hindmilk can sabotage a breast milk supply.
How babies grow
Babies grow and gain weight from drinking lots of breast milk. All breast milk is good, it is a nutritious and complete diet and babies need plenty of it. As a rough guide babies need about 800ml or 27 fluid ounces per day in the first six months. Whether it is foremilk or hindmilk or in-the-middle-upside-down-milk, babies need lots of milk to grow.
Quantity not quality
It is the volume of breast milk that is the important factor determining a baby’s weight gain not the fat content in a particular feed. Kelly Bonyata explains:
Whether it is foremilk or hindmilk or in-the-middle-upside-down-milk, babies need lots of milk to grow.Click To Tweet
The research tells us that baby’s milk intake (the volume of milk – not the amount of fat in that milk) is the only thing that has been correlated with infant growth in exclusively breastfed babies. […] average fat content of human milk is highly variable, but has not proven to be significant when calculating baby’s total energy intake or weight gain.
How breastfeeding works
Your breasts make milk on demand; so that the faster your baby drinks the available milk, the faster your breasts will make more milk to replace it, indefinitely. Breasts gauge demand by their degree of fullness:
- Whenever a breast is full, milk production slows down
- Whenever a breast is emptied regularly, milk production increases
The ideal way to make plenty of breast milk in the volumes your baby needs, is to feed your baby as often as he wants—letting him finish the first breast before offering the second side. Only your baby knows when one side is empty and whether he needs one breast or two, because breasts vary in how much milk they can hold (storage capacity). Storage capacity is explained more fully in One Breast or Two per Feed:
Breasts vary in their breast milk storage capacities. Where one mother’s baby might only want one breast per feed and not be hungry for two hours, another may need both breasts per feed and be hungry again in an hour. Let your baby decide how many breasts he wants at a particular feed by looking for his feeding cues and offering him plenty of opportunities to breastfeed.
Ignoring your baby’s cues and keeping to one breast to reach the hindmilk i.e. keeping your baby on one breast after he has emptied it, means the opposite breast gets little drainage, and slows down milk production. It’s like trying to build a milk supply by only pumping from one breast instead of pumping from both breasts.
If you have a low storage capacity then keeping to one breast is potentially denying your baby half his milk or more. Your baby may need the “hindmilk” from both breasts.
Increasing milk supply
If your baby falls asleep after less than ten or twenty minutes into a feed, breast compressions (gently compressing and releasing the breast during a feed) can get him to start sucking again by simulating another let-down of milk. By offering the other breast when the first is finished, and repeating breast compressions if needed, your baby will get the correct balance of foremilk and hindmilk automatically. Using both breasts when needed (and sometimes three or four!) will drive up and maintain your supply.
But what about foremilk and hindmilk?
Foremilk and hindmilk are the names given to subtle differences between breast milk at the start and at the end of a breastfeed.
- Foremilk describes the breast milk at the start of a breastfeed, it has a lower fat content, but has plenty of lactose the principal sugar in breast milk, not to mention all the other great ingredients1 in breast milk. Lactose is important for developing the brain and central nervous system, and provides 40% of a baby’s energy needs. Lactose helps with calcium and iron absorption and, along with other oligosaccharides (short chain carbohydrates) promotes the growth of friendly bacteria such as Lactobacillus bifidus to fight pathogens. As the breastfeed progresses, the fat content of “foremilk” steadily increases.2
- Hindmilk is the name coined for the breast milk towards the end of a feed as the breast empties. There is less of it but it has a higher fat content and all the other nutritious ingredients found in milk.
All milk is good
There aren’t two distinct types of breast milk with one being inferior to the other, it is a continuum of subtle changes. Hindmilk is released with every milk ejection (let-down). By the time feeding finishes on the first breast, the first milk from the second breast will contain more fat compared to the start of the feed on the first breast.3 The more frequently you breastfeed, and the emptier the breasts become; the higher the fat concentration in all the breast milk.
Quantity not quality
Remember, weight gain depends on the quantity of milk not just the fat content in the last few drops. Kelly Bonyata’s analogy with a hot water tap is useful. When you turn on the tap (start feeding) the water starts cold (low fat milk) but as it continues to run (as the feed progresses) the water gets warmer and warmer (higher fat). If you turn the tap off and on again quite soon, the water will still be warm (high fat milk will still be present at the start of the next feed).4 And you don’t need to run your tap for 30 minutes or an hour to get to the warmer water (if you do, call an engineer!)
What is foremilk hindmilk imbalance?
If a mother has lots of milk, more than her baby can comfortably handle, her supply will usually adjust downwards over time to meet her baby’s actual needs. In the mean time some babies may get an excess of lactose rich foremilk. This is sometimes referred to as foremilk hindmilk imbalance. Babies may also get foremilk hindmilk imbalance if a mother has a robust supply and continually takes her baby off the breast before he has finished feeding i.e. switches sides too soon.
Temporary lactose intolerance
In these situations the baby can find it difficult to digest all the abundant lactose in the plentiful foremilk causing temporary lactose intolerance or lactose overload. They may be fussy and uncomfortable with copious green, frothy and foamy nappies. The sheer volume of milk and high sugar content often means babies gain weight very well with foremilk hindmilk imbalance—even though they aren’t getting their “pudding”. However occasionally some babies may not gain enough weight in this situation. Advice to stay on one breast per feed or for a block of time can be very helpful with true foremilk hindmilk imbalance to ensure babies get a good proportion of higher fat milk. See Lactose Intolerance in Babies for further information and consult your breastfeeding specialist.
Confusion about green nappies
Health visitors who are already hooked on the idea of staying on one breast to get to the hindmilk may think this is an absolute certainty if you mention your baby has lots of green nappies. However the frequent scant green nappy of a baby not gaining weight is NOT the same as the copious frothy green nappy of a baby with lactose overload. Staying on one breast is not the answer for a baby with green “starvation stools”. See your IBCLC lactation consultant for further information if you are not sure what your baby’s nappies mean or whether block feeding is a good idea for your baby.
I kept to one breast per feed and my baby gained weight just fine!
Keeping to one breast may work perfectly if your storage capacity suits this regime. But be guided by your baby and his weight chart, not by any pre-set rules or clock-watching instructions to reach that elusive hindmilk at the bottom of the barrel.
My baby isn’t gaining weight
When a baby isn’t gaining weight they most likely need more milk, not more time on an already empty breast which will further reduce a mother’s supply. An extra 7-8 ml of high fat milk from the same breast is no substitute for the extra 70-80 ml of fore-hind-and-in-the-middle-milk they might need from the other breast. Check with your IBCLC lactation consultant for the reasons for low weight gain for your baby and see Baby Not Gaining Weight. For increasing milk supply see How to Make More Breast Milk.
Supplements are sometimes needed
If you have been following the advice to “stay on one breast to get to the hindmilk” for quite some time, your milk supply may be quite low. If your baby has not been gaining weight properly, or has been losing weight, he won’t be able to wait while you build your supply. He may need supplements (donor milk or formula) to build back his body weight so that he is strong enough to drive your milk supply all by himself.
Confusion about how breastfeeding works is causing some health professionals to unwittingly sabotage breastfeeding by recommending staying on one breast to get to the hindmilk: either as a general rule or as specific advice when a baby is not gaining weight. It is not helpful to think of breast milk as two or three different kinds of milk. All breast milk is good and babies need lots of it to grow. Breasts have different storage capacities and what works for one mother and baby may not work for another. Contact your breastfeeding specialist for tailor made recommendations for your unique situation. And forget about foremilk and hindmilk.