There’s a great injustice being done to dog food shoppers these days. And it can cost your dog dearly.
On pet food labels… the culprit is known as “Guaranteed Analysis”.
In essence, Guaranteed Analysis is the dog food industry’s lame version of the “Nutrition Facts” panel you see printed on the side of virtually every package of human food sold in America.
The whole point of the panel is to place a value on four nutrients…
- Protein
- Fat
- Fiber
- Moisture (water)
But these numbers can be seriously misleading.
Why You Can’t Trust the Reported Numbers
Guaranteed Analysis is supposed to be a reliable way to compare two or more pet foods. I say, “supposed to be”… because for reasons I’ll soon explain… the method falls miserably short of its intended goal.
You see… the system used for reporting the percentages fails to consider the water content… an especially serious error when comparing moist canned foods to dry kibble.
Even the Food and Drug Administration admits to the importance of this problem on its own website1 where it warns…
“To make meaningful comparisons of nutrient levels between a canned and dry product, they should be expressed on the same moisture basis.”
OK… let me show you why this is such a big deal… and how you can use what you learn here to more consistently choose better dog food.
How to Correct the Error Using Dry Matter Basis
Let’s say you have a can of dog food listing crude protein at 10% on its “Guaranteed Analysis”… in other words, its percentage content, just as it comes, right from the package. Or what the industry calls… “as fed”.
Doesn’t sound like much protein… does it?
But wait…
What if that same label showed the product contained 75% moisture? And what if you were to completely remove all that water from the can?
You’d be left with just 25% “dry matter”. Are you with me so far?
Good. Now, here’s the formula…
To determine the amount of protein… on a dry matter basis… simply divide the reported amount of protein… in this case, 10%… by the total amount of dry matter, 25%… and then, multiply by 100.
Dry Matter Protein Content = (10/25) x 100 = 40%
That gives you a dry matter protein content of 40%… a lot more than the label’s reported number of just 10%… four times the amount of protein claimed by the Guaranteed Analysis.
By the way… this same formula can be used to compute the dry matter fat and fiber contents, too.
When Dry Matter Basis Really Matters Most
Now, as long as you’re comparing canned food to canned food… this dry matter stuff isn’t all that important.
But when you’re comparing canned (wet) food to dry kibble… the issue becomes absolutely critical.
Take a look at this example…
Say you’d like to compare two products… a can of dog food with a bag of kibble.
The canned “wet” product lists protein content at 10%… and the dry kibble reports protein at 23%.
At first glance, the kibble looks like the easy winner. Right?
Not so fast. Now, let’s use our dry matter formula to level the playing field.
Using our old friend, Guaranteed Analysis… the wet food shows a water content of 75%… and the kibble, 10%.
OK, let’s now remove all the water from both dog foods. Take a look at the protein values after converting the data to dry matter basis…
Can you see how the canned product now lists 40% protein… compared to kibble’s 26% number?
Now, which one is the winner? If you had simply followed your first impression and chosen the kibble for its higher protein content… you’d have been dead wrong.
The wet food actually contains much more protein… on a dry matter basis… than the dry kibble.
The Bottom Line
On the surface… when reading the Guaranteed Analysis panel… canned dog foods almost always look inferior to their kibble counterparts.
But as you now know… looks can be deceiving.
So, don’t be fooled by a dog food label’s protein or fat numbers.
And remember, numbers are just that… numbers. They can’t reveal the true quality… or the digestibility… of the product’s proteins or fats.
Once again, be sure to take the time to look over the ingredients list. Your dog will surely be better off for your efforts.
- “Interpreting Pet Food Labels“, Center for Veterinary Medicine, U. S. Food and Drug Administration ↩
{ 4 comments… read them below or add one }
I think the information you have provided here is great – I spend a lot of time reading labels and trying to discern what is best for my dogs, but there were things I just didn’t know to look for, nor could I get much guidance from my vet (although I do lover her). I would love to see you do a similar analysis and provide some guidance on commercial cat diets. The more I look at those labels, the more I think commercial cat foods are even worse for cats than those prepared for dogs (or at least, some of them)…..cats are carnivores and if you ever take a look at those ‘special weight loss diets’ for cats….well, I lost sleep over it….I don’t want to give my young cats diabetes…..anyway, great job….food for thought….
This is very helpful, but causing me some grief. We are supposed to be keeping our dog on a reduced protein diet due to liver and kidney disease, and it appears we have been giving her much more protein than we realized. The labels are also misleading in that they list “guaranteed minimum % protein”, when the actual analysis is sometimes much higher. We are trying to feed her a quality dog food instead of Hills g/d that is almost as low in protein.
Granted protein on a percent dry matter basis is higher in the canned food, but you are paying for and filling your dog’s stomach with something that is 75% water. While I have not compared prices for dog food on a dry matter basis, I pretty strongly suspect you would spend less money and your dog would not have to eat so much to get his nutrition with kibble. If you feel your dog needs more protein, perhaps throw a little cottage cheese on top of his kibble, or, easier, buy a dry kibble formulated with more protein. How much protein does a dog require?
Hi Bev… You’re right. That’s one of kibble’s main advantages. In general, dry dog foods are certainly cheaper than wet foods. But we use dry matter basis because it’s the only way to properly compare meat protein content… not prices.