Foremilk and hindmilk
Also called foremilk/hindmilk, fore and hind milk, foremilk/hindmilk imbalance, lactose overload
Foremilk is the thinner milk at the start of a breastfeed, and hindmilk is the creamier, fattier milk later on. They aren't two kinds of milk: the fat rises little by little as the breast empties.
How it's said
Foremilk and hindmilk question: is this true or rubbish?
...the richer, creamier hindmilk, and the first third or so much paler and runnier, like milk mixed with a bit of water.
I've read about the foremilk and hindmilk thing and confused myself utterly!
Who says it
Where it came from
A 1988 paper in The Lancet suggested that a baby moved to the second breast too soon fills up on foremilk, which has fewer calories than hindmilk, and linked this to hunger and loose stools. Lactation professionals used the two words widely through the 1980s and 1990s.
Breastfeeding groups now stress there is no moment when foremilk turns into hindmilk. La Leche League GB calls what used to be known as foremilk/hindmilk imbalance lactose overload.