Thanks for consulting in Healthcare. I want to share wit you that i have never seen negative effects from NAN hypoallergenic. Yes, children can gain more weight when they eat formula, but from breastfeeding also , don t worry about it. Baby needs to grow. When he will more active- crawl, wa,lk, swim, then they will grow, calcium will better absorb by born. You see it is normal when children till 5 years round, have abdomen as baloon, it is because they don t have press and can t visit jim club. Thats why it is really important to do massage to baby, do exersises, sit and stand, crawl, on the big gymnastic ball for streching, joga for babies, then we will receive result Best regards Grow qucklier Dr.Svetlana