Through most of human history, there was no need to be able to digest milk after the age of weaning. Cows had not been domesticated. And Mom was busy with your little brother and sister. So humans evolved as creatures that, as adults, lose the ability to digest lactose, the major sugar in milk.
SCIENCE
Through most of human history, there was no need to be able to digest milk after the age of weaning. Cows had not been domesticated. And Mom was busy with your little brother and sister. So humans evolved as creatures that, as adults, lose the ability to digest lactose, the major sugar in milk.