As I am sure all of us have seen, there are cats that get fat and cats that stay slim.
Obviously something in the genetic make-up.
My garage girl, Tico, is half outside-inside, and is a little overweight, but not enough to worry about at the moment, but when she gets a little older, we will have to watch her closer.
Our two insiders, Grey and Boots, are pretty normal, and Boots is actually just the least bit "bony", but even for 14 years old, is extremely active, in his "rainman" neurotic way, and although Grey has the beginnings of a "pouch", he is otherwise neat and trim.
Now that we are close to breaking the genetic code, and thereby able to modify and delete certain characteristics, I am sure it is but a short time until there will be "designer" babies, human and otherwise, and then these problems of certain cats (and humans) having certain "negative" characteristics will be a thing of the past.
Except for the litter box problem, and that he LOVES to pounce in my lap from 10 feet away, I think I would like to have a 50 pound clone of Grey, our little Manx/Munchkin.