by Rachel Diner — For the first year of our lives most of what we eat is milk. In fact, dur­ing the first four months it is the only thing we eat. For moth­ers, both breast milk and for­mula are pop­u­lar op­tions for get­ting a baby nour­ished, and while both breast milk and for­mula have the es­sen­tials needed to sur­vive,...