I have five cats who get Iams adult formula ONCE A DAY. Dump about a cup into the bowl and leave it. Let the cat decide when to eat, and you will soon see that it regulates its eating patterns and will lose weight. Make sure there's plenty of fresh water and do NOT give in to it when it howls and merowls for more food. It'll stop that shit in a few days and be just fine. Good luck.
