How to compare nutrition in pet foods
by Michael Rosenstock
Sadly, pet food labels are misleading when it comes to comparing their nutritional components. The Guaranteed Analysis listings on pet food labels reflect the federal Food and Drug Administration (FDA) “As Fed Basis” testing. This testing doesn’t consider the product’s moisture content, which acts to dilute the results of all reported nutritional data: protein, fat and fiber.
The FDA stresses the importance of considering moisture on its website “To make meaningful comparisons of nutrient levels between a canned and dry product, they should be expressed on the same moisture basis.” 
“Dry Matter Basis” uses a simple formula for comparing guaranteed analysis of multiple products on equal footing by removing all moisture. This is important to all pet owners, and is of critical importance if protein or fat needs to be controlled for medical reasons. The formula is simple and easy to use with our cellular phone calculator. Here are the steps:
1.Determine the amount of Dry Matter in a product. Dry Matter equals 100% minus the moisture indicated by the label. (If the label reads “moisture 75%” then Dry Matter is 100% minus 75% and equals 25 %.)
2.To find the actual percentage of nutrients, multiply the percentage of the ingredient by 100 and divide by the Dry Matter total (in the above case 25%). by 100 and divide by the percentage of the ingredient. So, again using the example above, if the protein is 8% of the total product, its dry matter percentage would be 8 x 100 divided by 25, or 40%.
A Comparison of Nutrition in Pet Foods
Look at how some pet foods compare. Pedigree Adult Complete is the top selling dry dog food according to Supermarket News. I compared the dry and wet version of that brand for nutrient content. Then I compared the wet and dry products of a brand currently reviewed as one of the top in the industry and used by friends who prefer feeding kibble.Pedigree Adult Complete (dry)Pedigree Choice Cuts in Gravy (canned) LabelDry Matter Basis LabelDry Matter BasisMoisture12%Moisture82% Protein21%24%Protein8%44%Fat10%11%Fat3%17%Fiber4%5%Fiber1%6%Total 40% 67%* Percentages are rounded up to the nearest whole number Zignature Zssential Fulmula (dry)Zignature Zssential Formula (Canned) LabelDry Matter Basis LabelDry Matter BasisMoisture10% Moisture78% Protein32%36%Protein11%50%Fat16%18%Fat5%23%Fiber5%6%Fiber1%5%Total 60% 78%
The totals listed under Dry Matter Basis are the rounded result of utilizing the formula and thereby removing all moisture from the label’s Guaranteed Analysis listing. Now we can compare pet foods on an even playing field. As you can see from the tables, Pedigree’s canned food has almost twice the protein of their kibble – 44% versus 24%.
Adding up our protein, fat and fiber leaves a lot of room, particularly with your dry foods. So what’s left? The remainder is the good, the bad and sometimes the ugly. Needed vitamins and minerals do make up some of the volume and are critical to your pet’s health. The rest, after applying the “Dry Matter Basis” formula, is filler. The word filler shouldn’t put you in a panic, as everything we eat includes nutritionally unimportant components. It’s the amount of filler and its contents we care about.
To determine if the nutrition in pet foods is good or bad, look at the ingredients. The FDA requires that ingredients be on the labels in their order by volume, high to low. You probably don’t want a food whose label begins with ingredients that are nutritionally low in value, such as grains. Grains are full of calories and little else useful to our pets. Be careful to look for ingredients you can’t pronounce, as they are often manmade, or created through extensive processing. Look out for preservatives BHA and BHT. They are very common in commercial dog foods, have been linked to certain cancers, and are potentially toxic. Citric Acid (also known as vitamin C and ascorbic acid) is often listed as a preservative, but is a natural ingredient that should be part of a pet’s diet. The only potential concern is that 85% of it comes from China.
So choose carefully. Pets are family.
 “Interpreting Pet Food Labels”, Center for Veterinary Medicine, U.S. Food and Drug Administration.
Michael Rosenstock is the CEO of Finest Fetch dog foods.