petey the cat is really all that

So now that I have changed the cat's diet - he looks ten years younger (tho he is only 8), his coat is stunning, he has lost a lot of weight, he has the energy of a kitten, and folks keep commenting "oh my god he looks so amazing" and " i did not know Petey could run" and so what I want to know is Where Can I Get Some of That -
That's right - WTF can I eat more/less of so I am not the old Petey -meaning lazy, irritable, with bad skin.
Anyways, I have to go and run his bath - he has a hot date tonight. I am staying in and cleaning his litterbox.