I have the same problem with Calypso, who at 2 yrs has put on quite the belly. Meal rationing is part of it, but I'm not sure about the rest.

Are there kitty crunches? Little ab machines for kitties?

My problem is limiting the food that Calypso gets, when I have another cat in the house that is clinically underweight. So Bonnie needs all the calories she can get, and C needs hers limited.

Seems with one cat, it would be somewhat easy to limit the amount of food they get daily, thus lowering their total caloric intake. And slowly over time they'd loose weight.