The Neolithic Revolution brought about significant change evolutionary changes in humans; namely the transition from a hunter-gatherer lifestyle characterized by foraging for food to an agricultural lifestyle. This change occurred approximately 10,000-12,000 years ago (CITE Ag rev in prehist)(CITE 5). Humans began to domesticate both plants and animals, allowing for the maintenance of constant food resources. This transition quickly and dramatically changed the way that humans interact with the environment, with societies taking up practices of farming, and animal husbandry. However, human bodies had adapted to their previous foraging lifestyle. The slow pace of evolution in comparison with the very fast pace of human advancement allowed for the persistence of these adaptations in an environment where they are no longer necessary. In human societies that now function in a vastly different way from the hunter-gatherer lifestyle, these outdated adaptations now lead to the presence of maladaptive, or mismatched, traits. (CITE 5)

It should be noted that some modern human populations engage in hunter-gatherer practices.