▁ ▁Cor relation ▁with ▁ob es ity ▁ ▁Ex pos ure ▁to ▁ant ib iot ics ▁early ▁in ▁life ▁is ▁associated ▁with ▁increased ▁body ▁mass ▁in ▁humans ▁and ▁mouse ▁models . ▁Early ▁life ▁is ▁a ▁critical ▁period ▁for ▁the ▁establishment ▁of ▁the ▁int est inal ▁micro bi ota ▁and ▁for ▁met abol ic ▁development . ▁M ice ▁exposed ▁to ▁sub ther ape ut ic ▁ant ib i otic ▁treatment ▁– ▁with ▁either ▁pen ic ill in , ▁van com yc in , ▁or ▁ch l ort et racy cl ine ▁had ▁alter ed ▁composition ▁of ▁the ▁gut ▁micro bi ota ▁as ▁well ▁as ▁its ▁met abol ic ▁capabilities . ▁One ▁study ▁has ▁reported ▁that ▁m ice ▁given ▁low - d ose ▁pen ic ill in ▁( 1 ▁ μ g / g ▁body ▁weight ) ▁around ▁birth ▁and ▁throughout ▁the ▁we an ing ▁process ▁had ▁an ▁increased ▁body ▁mass ▁and ▁fat ▁mass , ▁acceler ated ▁growth , ▁and ▁increased ▁he p atic ▁expression ▁of ▁gen es ▁involved ▁in ▁ad ip ogen esis , ▁compared ▁to ▁control ▁m ice . ▁In ▁addition , ▁pen ic ill in ▁in ▁combination ▁with ▁a ▁high - f at ▁di et ▁increased ▁fast ing ▁ins ul in ▁levels ▁in ▁m ice . ▁However , ▁it ▁is ▁unclear ▁whether ▁or ▁not ▁ant ib iot ics ▁cause ▁ob es ity ▁in ▁humans . ▁Studies ▁have ▁found ▁a ▁correlation ▁between ▁early ▁expos ure ▁of ▁ant ib iot ics ▁( < 6 ▁months ) ▁and ▁increased ▁body ▁mass ▁( at ▁ 1