The hormone imbalance for some can make it harder to maintain as I think it slows some metabolisms down, but it's a small difference.  And you can just eat a smaller amount and be fine.  We don't get it either, and many of us have PCOS.  Mine is bad enough that I now get cysts under my breasts that got mistaken for potential cancer, but the only thing I've noticed weight wise is if I do fuck up and gain some weight it's a bit harder to lose it again.  I do, it's just harder.