@catman44,
Just speculation, but I bet the cat is in poor health. Maine Coon Cats seem to have a natural predispositon to be what we would politely call "stout". If you're feeding it and there is no weight gain, there is probably something seriously wrong.
Calling the ASPCA would probably be unhelpful in this case. That doesn't mean you shouldn't, but don't get your expectations too high.