I'm quite strict, one of mine used to have a tendency to bully the others away from their bowls when I first got him, and had a tendency towards weight gain. How old is Daisy? If she's a middle aged or older cat and is constantly hungry and not putting on weight, it would be worth getting her thyroid checked. Another thing you could try is some sort of puzzle-feeder? Stimulating a cat's mind and making it work a bit for food mimics the hunt/eat process they would naturally follow and can be useful in cats that do not self-regulate their intake - the food seems to satisfy them more, and they are also getting some exercise.