Key takeaways: Breast milk gets gradually higher in fat as the breast empties. There aren’t two separate milks. Letting your baby finish the first breast before offering the second is usually enough. Green, frothy stools in a gaining, content baby are usually not a concern, and timing feeds by the clock isn’t needed.
You may have heard about “foremilk” and “hindmilk” and worried that your baby isn’t getting enough of the fatty milk. Here’s what the research actually shows.
What They Are
- Foremilk is the milk at the start of a feed. It’s typically lower in fat.
- Hindmilk is the milk later in a feed. It’s typically higher in fat.
There’s no switch point. The fat content gradually increases as the breast becomes emptier, because fat sticks to the milk ducts and is pushed out more as the feed goes on.
How Fat Content Works
The fat content depends on how full the breast is. A fuller breast gives lower-fat milk; an emptier breast gives higher-fat milk. Total fat intake over 24 hours is what matters most for growth.
What Is “Foremilk-Hindmilk Imbalance”?
This term describes a baby who gets a lot of lower-fat milk, often with a large milk supply. Signs that have been described include:
- Frothy, green stools.
- Gas and fussiness.
- Rapid weight gain or, sometimes, slow gain.
A small study in 1988 by Woolridge and Fisher described babies with these symptoms that improved when mothers let babies finish one breast before switching. Evidence on this topic is limited.
What to Do
- Let your baby finish the first breast, coming off on their own, before offering the second.
- Don’t time feeds on each side by the clock.
- If you have oversupply, an IBCLC can help with strategies like block feeding. Don’t start block feeding without guidance, since it can lower supply too much.
Green Stools Alone Usually Aren’t a Problem
Green stools can happen for many reasons, and are usually fine in a baby who is gaining weight, feeding well, and content.
Talk to your baby’s doctor or an IBCLC if: your baby isn’t gaining well, seems very fussy or uncomfortable, has blood or mucus in the stool, or has fewer wet diapers.
The Bottom Line
Foremilk and hindmilk are part of one continuous milk. Feeding on cue and letting your baby finish the first breast takes care of it for most families.
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Sources
- Woolridge MW, Fisher C. Colic, “overfeeding”, and symptoms of lactose malabsorption in the breast-fed baby: a possible artifact of feed management? Lancet. 1988;2(8607):382-384.
- Kent JC, Mitoulas LR, Cregan MD, et al. Volume and frequency of breastfeedings and fat content of breast milk throughout the day. Pediatrics. 2006;117(3):e387-e395.
- Daly SE, Di Rosso A, Owens RA, Hartmann PE. Degree of breast emptying explains fat content, but not fatty acid composition, of human milk. Exp Physiol. 1993;78(6):741-755.
- Lawrence RA, Lawrence RM. Breastfeeding: A Guide for the Medical Profession. 9th ed. Elsevier; 2022.
This article is for general education and is not a substitute for individualized medical advice. Always talk with your baby’s health care provider or your own provider about your specific situation. If you think your baby or you may have a medical emergency, call 911.
