Our problem is twofold: one, we are haunted by a Neighbourhood Stray, who slides ninja-like into the kitchen and nicks the catfood whenever our collective backs are turned. Since he no longer sprays the kitchen I am less worried about him, but it effectively means we have to give our kitties enough food for 5 cats twice a day, because an ongoing supply in the bowls means that Neighbourhood Ninja Tom will simply wax fat and encouraged.

Also, like first_fallen, I suffer from cats who bolt too much and throw it up again immediately, and rationing them to a defined amount seems to reduce the incidence of this.