When I rented my first place with roommates, I adopted 2 cats that had been in a shelter for over a year. For 6 months we fed them whenever the bowl was empty. One day I look over and realize their bellies were brushing the ground! Since the cats had been on a feeding schedule before, we didn't realize they would eat as much as we gave them and the slow fattening wasn't noticed by any of us until it was grotesque. After that day, I was the sole cat feeder and they slimmed down again.