Metformin related question?

i'm female,29,and my question is about metformin,i have pcos and am taking it,as it is supposed to help with insulin resistance that is involved in having pcos,and to help lose weight i'm told. Have been lucky i've not gained any,and have lost a stone over nearly 2 years. I feel the metformin was a great help,and that i did make dietary changes that i think may have helped. What i would like to know is if any of you have a idea,about what should be changed in eating along with taking metformin. Thanks