We've had cats all our lives, always indoor cats, and we've always had food available, all the time.
This "free-feeding" has worked fine till the current cat, who ate her way up to obesity. Then, she got diabetes, and lost a lot of weight.
Now she is stable, on a vet-approved diet, and the appropriate weight. Unfortunately, now she is no longer sick, she seems determined to eat her way back to obesity. Today, for example, she had finished her entire days allowance of food by lunchtime.
So, do we just have to be hard-hearted and ignore her pathetic begging? Will she ever get used to eating less? She's 12, btw, and woefully inactive. She even lies down to eat.