Tried on this romper in size 00P. It fits like a loose size 0P in the waist. I would size down. The belted tie waist was 1" above my belly button aka natural waist. Above the belt the waist is very wide and you can see how the extra material kicks out on the left photo. If you're thinner belting this romper will cause the material at the waist to bunch a lot. I've seen others wear something over it to hide the fit issues at the waist. I linked to other cute rompers @liketoknow.it http://liketk.it/2vC3A #liketkit #LTKunder50 #LTKunder100