No, you really can’t. And here’s why…
Say you’ve got a pair of old leather boots… some used motor oil… and a scoop of sawdust1.
Now, grind them all up… blend them together… and send that whole concoction to a food testing laboratory… for analysis.
And the results? This toxic medley of rubbish contains…
- Protein 32%
- Fat 18%
- Fiber 3%
Now, if you look only at the “raw data”… the numbers make this funky brew look pretty good… in fact, just as good as any quality dog food.
The leather provides the protein. The motor oil supplies the fat. And the sawdust contributes the fiber.
Not exactly something you’d ever want to feed your dog. See how easy it is to be fooled?
Why You Should Be Skeptical of Published Percentages
Well, naturally, dog food companies want their “numbers” to look as good as possible. So, many of them shrewdly manipulate their recipes to tweak the percentages.
By adding proteins of dubious nutritional value companies can easily take advantage of your unguarded trust.
That part of a dog food package where manufacturers are required to reveal these proportions is called the “Guaranteed Analysis” panel.
There are two very good reasons why you must never trust the protein figures on this “panel” as your sole means of comparing dog foods. The Guaranteed Analysis percentages fail to allow for…
- A dog food’s moisture content
- The quality and digestibility of the protein itself
First, let’s look at the issue of moisture content…
A Better Way to Compare Protein Content
Because different dog foods contain different amounts of water, it’s pointless to compare their protein contents. This is especially true when you put a dry kibble up against a canned product.
A canned dog food can easily contain 70% water. And that can make a kibble… at least on paper… look like it has much more protein than its canned food rival.
Yet without the water… this same can of food can sport a significantly higher percentage of protein than the kibble.
Now, to make a fair comparison, you must first mathematically remove all the water from both foods.
A dog food’s percentage that is either protein, fat or fiber… minus the water… is known as its dry matter basis. Dry matter basis is a much better way to compare the protein content of different dog foods.
Now, let’s take a look at the issue of protein quality… and digestibility.
What Is Biological Value and Why Does It Matter?
Not all proteins are created equal.
You see, proteins are nothing more than a chain of connected chemical building blocks… building blocks known as amino acids. All in all, there are 22 different amino acids required by dogs for their very survival.
Twelve of these can be manufactured by the dog’s body itself. The other ten cannot… and must come directly from a dog’s diet. That’s what makes them “essential” amino acids.
Certain protein sources are simply better than others… and provide a richer blend of amino acids. These better proteins have what’s referred to as a high biological value.
The Critical Factor of Protein Digestibility
Now, what good is it to have a dog food made with a higher quality protein… if it’s not also easy to digest?
To better understand protein digestibility, it’s important to recall that digestion itself is the gradual breaking down of any food into smaller and smaller components… small enough to pass through the walls of the intestines… and into the bloodstream.
A dog food with high protein digestibility is one that can be broken down into smaller… easy-to-absorb components… quicker than others.
That’s what makes meat such a desirable dog food ingredient. A dog’s digestive system is simply better able to handle it.
By the way… protein ingredients that meet both requirements… high biological value and high digestibility… almost always come from animal sources.
Don’t Be Fooled by Stated Protein Percentages
Though not as bad as that crazy “leather boots, motor oil and sawdust” combination… many dog foods can seriously mislead you… if you rely solely on their published protein percentages.
So, watch out for those dubious protein numbers whenever you shop for dog food.
- Pitcairn RH, Pitcairn SH, Dr. Pitcairn’s Complete Guide to Natural Health for Dogs and Cats, 2005, Rodale Press, p. 12 ↩