How Kibble was Born
The shift in dog food began in the 1860s, in Ohio, when an enterprising young chap thought to make a ship’s “hardtack” into a convenient dog food, when he noticed shipyard dogs feasting on hardtack left-overs. Hardtack is basically just flour and water and some added nutrients (traditionally, lard) that will sustain one for a time, but not indefinitely.
It’s purpose was for long ocean voyages. Hardtack is fairly indestructible, transports light, and doesn’t really spoil in any condition as long as it doesn't get wet. And a dog will generally live a surprisingly long time on a diet of dry dog food based on this principle.
Of course over time as the science improved, the idea was that all essential nutrients known to be needed and beneficial could be easily (artificially) included. But this is technically like smashing a cup of supplements into a paste then forming and baking that into a bone shape — which sounds bad when I put it that way, but theoretically, you would think that it should still work. All the nutrients are there, the calcium, the calories, etc.
But it doesn’t work. Or at least not well. Just like trying to survive on only pills and supplements, it has been repeatedly demonstrated that eating the food with the desired nutrients–in as unmolested a form as possible, provides health benefits that in some cases science can’t really explain yet, but which nonetheless makes perfect common sense.
Real dog food can contain hundreds of micronutrients, carotenoids and minerals that help with inflammation, reduce cancer risks, and often provide a long list of health benefits.
Rather than relying on a multivitamin or beef extract #5, both you and your dog will be healthier by occasionally eating a carrot, some broccoli, or kale. Maybe a beet now and then. Simply rotate a variety of foods such as sweet potatoes and peas that provide a range of essential nutrients.