I have the exact same problem. See "Fat Kitty". I have three cats and one of them is a huge porker. The vet has told me the same thing. They all dig into each others bowls depending on how much food they have left. I have been reading about the different foods and have decided to change their food to that Euka....(I forget the exact name).
I am picking some up this week-end. They seem to be meowing for food everytime I turn around, yet looking at Gabby, I know their not starving.
Yeah, unfortuantley with a multi cat household it is hard. I have one piggy and I know she needs to loose weight. I am not the perfect cat mom and dont have the time to feed 11 cats at different times. Besides which, I do not feed them wet food. She will just have to be a little overweight. Eukanuba is a very good food. It may help with the weight because they seem to eat less of it. They get more of the nutrients from one serving. If there is just 2 cats, they I might suggest buying a bag of the light formula and a bag of regular and mix them.(They are not fat...they are fluffy)..