Comparing Protein in Commercial Pet Foods

Comparing protein in commercial pet foods is critical to determine which food is best for your dog or cat – and determining how you spend your money.

Comparing protein in commercial pet foods can be confusing, no matter how savvy a pet food consumer you are. That’s why, in this post, I want to get back to basics and, in particular, discuss the “trick” of comparing dry foods with moisture-rich foods (and the surprising result when doing this). I always find this to be an interesting exercise and I hope you will, too.

To figure out the amount of protein in commercial pet foods, we must turn to the the Guaranteed Analysis on the food’s label. The Guaranteed Analysis tells us the total percent of the food that comes from protein, fat, fiber and moisture (and sometimes other nutrients, like calcium and phosphorus). But we cannot accurately compare the protein content in commercial pet foods based on the Guaranteed Analysis. Why not?

Guaranteed Analysis simply is not an accurate way to compare the protein in commercial pet foods because it takes into account only the weight of the food prior to processing, not after. This measurement, which includes the food’s moisture content, is called the As Fed basis.

Here are a few examples of the moisture content of various raw proteins, according to the USDA’s Nutrient Database:

• Chicken leg meat – 76% water
• Dark meat chicken – 75% water
• Ground 85%/15% beef – 66% water
• Lean lamb shank – 74% water

As you can see, various cuts of raw meat are about three-quarters water. But, the post-processing weight of the meat can change dramatically depending upon the type of product. On a post-processing basis, kibble contains far less moisture (about 6 – 10%) than canned or raw food (about 70 – 75%).

This is why we cannot accurately compare pet foods based on the manufacturer’s listed As Fed analysis. It simply is not accurate because it contains the food’s pre-processing moisture content.

The Solution to Determining Protein Content in Commercial Pet Foods: Dry Matter Basis

The only way to accurately determine the protein content of commercial pet foods in comparison to other foods on the market is to mathematically “remove” the food’s water content. Doing this converts the “As Fed” percentages reported on the Guaranteed Analysis to a Dry Matter (DM) basis. Using DM basis enables us to compare “apples to apples”, regardless of whether you are comparing kibble to kibble, kibble to wet food, kibble to raw food, etc. It simply doesn’t matter, because by removing the water, you are “leveling the playing field.”

Fortunately, comparing the protein content in commercial pet foods on a Dry Matter basis is quite simple once you get the hang of it. Here’s how in three simple steps:

• Step 1: Figure out the percentage of dry matter in the food.
  We start with 100% because the total contents of the food are 100% of the food. To determine how much of the total is dry matter (no water), we subtract the percent of the food’s listed moisture from 100%. For a kibble containing 10% moisture, we will do the following:
  100% – 10% = 90%
  This food contains 90% Dry Matter
• Step 2: Figure out the percent of the food’s protein on a Dry Matter basis.
  Next, we take the percentage of crude protein listed under the Guaranteed Analysis and divide that number by the dry matter number we determined in Step 1. Let’s say the food in question contains 20% protein on an As fed basis. We divide 20% (protein) by 90% (Dry Matter) and multiply the result by 100, as follows:
  20/90 =.22 X 100 = 22%.
  This food contains 22% protein on a DM basis.
  Note that you can use this same formula to determine the DM amount of fat and other listed nutrients.
• Step 3: Compare the protein content of different foods.
  Now, let’s compare the DM protein content of our kibble with the DM protein content of a canned food containing 75% moisture and 10% protein. We’ll do Steps 1 and 2 again. First, we subtract the listed percent of moisture from 100 (100 – 75 = 25). This food contains 25% Dry Matter. Next, we divide the 10% protein by the food’s 25% DM and multiply this by 100. (10/25 = .40 X 100 = 40). This food contains 40% protein on a Dry Matter basis.We just learned that the canned food contains almost double the amount of protein on a Dry Matter basis than the kibble (40% compared to 22%), even though at first glance the kibble appears to have double the protein than the canned food.

Real-World Dry Matter Comparisons

In our chart, below, we have 3 turkey-only, grain free diets: kibble, raw and canned. Note that these products are all from the same company. Let’s compare the protein of each product as listed on the Guaranteed Analysis and on a Dry Matter basis:

As you can see, the foods that at first glance appear to contain the least protein actually contain the most protein when we remove the moisture! Why is this?

When we remove moisture from a food, the percentage of protein and other nutrients in the food jumps significantly. So, the more moisture we remove, the more the percentage of the other nutrients will increase.

This is why it’s so important not to judge a book by its cover – or, in this case, a food by it’s Guaranteed Analysis. To level the playing field, we must convert foods to a Dry Matter basis.

I hope this article has helped to demystify figuring out how much protein is in your dog’s food – and how to choose the best food for your dog or cat.

The post Comparing Protein in Commercial Pet Foods appeared first on Pet Food Diva.