Garbage In, Garbage Out

Garbage in, garbage out.

That’s about the only thing I remember from an Intro to Computer Science course that I suffered through like a century ago. Turns out that pithy motto could also be used for an Intro to Dog Food course.
You raw-feeders know what I mean, particularly if you ever switched your dog from kibble to raw and marveled at how much less your pooch pooped. Why? Cuz there’s no garbage in raw, almost everything in the food is used by the body.
Let's take a moment to appreciate the marvels of the digestive system. This anatomical wonder breaks down, sorts and sifts the food up to the micro level and distributes it throughout the body. Certain proteins go to the bones, other ones are delivered to the brain and so on.

It's hard to fathom that this insanely complex distribution process runs on autopilot in the most efficient manner. You've got enzymes and acids working away at breaking down the food. There’s even “good” bacteria multiplying like rabbits so they block out the “bad” bacteria. (Wish I could hire some to block out some of the strange calls I get). Makes you realize that a meal is more than a "chew ‘n poo" as my portly cousin Irwin the security guard says. By golly, the digestive system is as intricate an arrangement as the rotation of the planets.
So here’s the thing, as with any part or organ of the body, you don’t want to overburden it. A slim physique puts less stress on the heart. A less fatty diet won't block your arteries - you get it...The idea is to make life easy organs and systems lest they deteriorate and conk out. 
Raw is easier to digest, pure meat and veggies are basically just proteins, vitamins, water and other good stuff that's hard to pronounce. No need to process useless filler that ultimately turns into (bad) fat or poop. Natural food as smooth on the digestive system as a crooner in a piano lounge.
Good food in, Good health out.

Not as catchy a motto, but just as true.