Stop screen from stretching in build?

When I test my game in fullscreen editor it leaves black space around the screen to keep the resolution I set (how I wanted it). When I play it fullscreen in standalone build, the screen is stretched so that there is no black space along the edges. This creates all sorts of problems with game objects moving off screen and things scaling incorrectly. Is there anyway for me to set it so that when you play the game in the standalone build (Im using a mac) that when it goes full screen it keeps the black edges around?