Small Cat is skinny and picky. She gets too thin sometimes. She has special 'sensitive tummy' food. I keep a constant eye on her and often buy 'mother and newborn kitten' high calorie mousse to keep her weight up. She likes to eat little and often through the day.
Big Cat is a feline dustbin. He hoovers up everything in his path. His lifetime ambition is to become very, very fat.
So, I put Small Cat's food down. She eats half a teaspoon full. She wanders off. Big Cat hoovers up the rest. Small Cat returns an hour later to find an empty bowl. She's hungry. I put more food down... you see how this goes?
It's fine (if annoying) when we're all home, but on a normal work day there's no one home for most of the day.
How can I make sure Small Cat has a constant source of her special food available to her, without Big Cat constantly finishing it and becoming the size of a horse? I can't think of a way.