No fats arent safer from gunshots then a normal human being. Bullets go very fast and speed kills. Fat isnt some lead vest and it wont slow down the bullet enough to stop it from getting to the organs. If anything its more dangerous for fatties to get shot because if they survived and there is no exit wound it will be harder to find for the trauma doctor to locate the bullet since it probably tumbled inside the body which will also make the doctor to stop the bleeding.  All in all I wouldnt use a bullet to kill fatties (wasteful) I would just trip them and let gravity do rest of the work (which is literally a call I did today which I will write a post about tomorrow)