My boy, Rio, was crying for food, then not eating it - he's a great hunter and I thought it might be worms. i wormed him but it took a full week before he was eating normally, so now I'm not sure. He prefers wet food, and i let him have that to ensure he has fluids as I rarely see him drinking, but he is in the utility room at night and the kibble is eaten by morning.
Hope you find the answer shygirl. In my experience 20 to 25 is pretty well max for cats.