An insert for an article of clothing that includes a body-covering portion and a closeable portion having a zipper structure that secures the body-covering portion about a body of a wearer, the body-covering portion defining an outer circumference when the closeable portion is closed, the insert comprising: a body portion comprising a flexible material, the body portion defining a perimeter including a first edge and a second edge; a first zipper disposed along the first edge and securable to a first portion of the zipper structure of the body-covering portion of the article of clothing; and a second zipper disposed along the second edge securable to a second portion of the zipper structure of the body-covering portion of the article of clothing; wherein the perimeter of the body portion is for increasing a size of the outer circumference of the body- covering portion when the first and second zippers are secured to the zipper structure; wherein the zipper structure of the body-covering portion of the article of clothing includes a first track and a second track, the first zipper comprising a third zipper track and a first slider portion that couples the first and third zipper tracks, and the second zipper comprising a fourth zipper track and a second slider portion that couples the second and fourth zipper tracks; and wherein the first and second slider portions each include a top component coupled to a bottom component by a hinge or pivot structure and the hinge or pivot structure permits the first slider portion to open and facilitate coupling between the first and third zipper tracks and the second hinge or pivot structure permits the second slider portion to open and facilitate coupling between the second and fourth zipper tracks. a body portion comprising a flexible material, the body portion defining a perimeter including a first edge and a second edge; a first zipper disposed along the first edge and securable to a first portion of the zipper structure of the body-covering portion of the article of clothing; and a second zipper disposed along the second edge securable to a second portion of the zipper structure of the body-covering portion of the article of clothing; wherein the perimeter of the body portion is for increasing a size of the outer circumference of the body- covering portion when the first and second zippers are secured to the zipper structure; wherein the zipper structure of the body-covering portion of the article of clothing includes a first track and a second track, the first zipper comprising a third zipper track and a first slider portion that couples the first and third zipper tracks, and the second zipper comprising a fourth zipper track and a second slider portion that couples the second and fourth zipper tracks; and wherein the first and second slider portions each include a top component coupled to a bottom component by a hinge or pivot structure and the hinge or pivot structure permits the first slider portion to open and facilitate coupling between the first and third zipper tracks and the second hinge or pivot structure permits the second slider portion to open and facilitate coupling between the second and fourth zipper tracks.