It really isn't ever a good thing to do on a single-breasted suit. On a double-breasted suit it can be done, which alters the wrap of the coat. You can take in the jacket a little bit that way, but you need to make sure the buttons aren't too close to the pockets. Wraps can vary a lot amongst double-breasted suits, so this can be adjusted a little before it starts to look off. Single-breasted suits look off even if you just move the buttons a little. Moving buttons will only adjust the front. Giving a double-breasted suit less wrap will accommodate a larger belly in front, but it does nothing for all around girth.