Can anyone help.... how long does it take from eating something for it to effect breast milk? My 7 week old has been suffering on and off (arching back, posseting, sickness, crying etc) but only after some feeds so I am assuming that she is reacting to something I have eaten. I have been cutting out certain foods (dairy, chocolate, caffeine, onions etc) but was wondering what it was that I am eating that is effecting her. Once I have a rough idea of how long it takes for the food I've eaten to affect my breast milk I can then work out what it is that is affecting her. I am desperate to make things more comfortable for her.