Weight gain on a copper IUD

I've been on birth control for about four years now but am hating the weight gain that I've gotten with it, and having a hard time getting rid of it. I'm thinking about switching to a copper IUD because of the no hormones in hopes of losing some of this weight. My question - for those of you who have been on a BC and switched to a copper IUD, was it easier to lose weight after?! Also, I've always have extremely short and light periods with minimal cramps, are my periods going to get a whole lot worse, or is that mostly for people with regular to heavier periods