(Phys.org)—The transition from breastfeeding to a nonmilk diet is a developmental milestone, influencing future health and survival of mammals, including humans. Breast milk is highly beneficial to infants, conferring easily digested nutrients and energy, while also strongly enhancing young immune systems. However, as infants grow, their metabolic needs outstrip the resources that mothers can provide, and the transition to nonmilk food becomes necessary.