Understanding Dog Food Labels: Part 2

You look at a bag of dry food and the guaranteed analysis says it contains 21% protein. The same company’s wet, canned food guaranteed analysis only has 8% protein. The dry food has more protein, right? Wrong! The nutritional content of dry food and wet food cannot be compared directly. That type of comparison would be like comparing apple to oranges. This post shows how to make the comparison an accurate, apples-to-apples analysis. As with all pet food labeling, it requires you take a calculator or smart phone with a calculator to the store.

This post shows how to make the comparison an accurate, apples-to-apples analysis. As with all pet food labeling, it requires you take a calculator or smart phone with a calculator to the store.

Below is the guaranteed analysis we used in the first post on labels.

Guaranteed Analysis-Dry Guaranteed Analysis-Wet
Crude Protein 21% 8%
Crude Fat 10% 6%
Crude Fiber 4.5% 1.5%
Moisture 12% 78%

The guaranteed analysis of dog food includes the water content of the food. Water increases the volume of the food but does not add any other nutritional content. To compare the protein, fat, fiber and carbohydrate content of dry to wet we need to eliminate the effect of the water content.

Think of the diet as being made up of food and water and that totals 100%. The dry food above has 12% water. That means it has 88% food (100% – 12% = 88%). The guaranteed analysis says that there is 21% protein in 100% of the diet. But only 88% of the diet is food. So how much protein is there in the food? If the percent protein is divided by the amount of food it gives the amount of protein in the food without the water. The equation is:

21%/.88 (.88 is 88% in decimals) = 23.9%

The food, minus the water, in the dry diet actually contains almost 24% protein.

Now, let’s calculate the protein in wet food. It contains 78% water, so the equation is:

8%/.22 (100% – 78% = 22% or .22) = 36.4% protein.

The wet diet contains a higher percentage of protein in the food, minus the water.

The same calculations for the other ingredients are listed in the table below.

Guaranteed Analysis-Dry Guaranteed Analysis-Wet Moisture Adjusted-Dry Moisture Adjusted-Wet
Crude Protein 21% 8% 23.9% 36.4%
Crude Fat 10% 6% 11.4% 27.3%
Crude Fiber 4.5% 1.5% 5.1% 6.8%
Moisture 12% 78%

But what about the carbohydrates? The previous post on food labels can help with that.

Carbohydrates are what are left after subtracting everything else from 100.

For the dry it is:

100-21-10-4.5-12-3(Ash) = 49.5%. But that is with the water content. Using our new information the equation is:

49.5%/.88 = 56.3%. The dry food is primarily made of carbohydrates. Without high carbohydrate content, dry food cannot be “popped” into dry kibble.

Now, let’s calculate the carbohydrates in the wet food.

100-8-6-1.5-78-3(Ash) = 3.5%

Minus the water:

3.5%/.22 = 15.9% carbohydrate.

Now our table is complete:

Guaranteed Analysis-Dry Guaranteed Analysis-Wet Moisture Adjusted-Dry Moisture Adjusted-Wet
Crude Protein 21% 8% 23.9% 36.4%
Crude Fat 10% 6% 11.4% 27.3%
Crude Fiber 4.5% 1.5% 5.1% 6.8%
Moisture 12% 78%
Carbohydrates 49.5% 3.5% 56.3% 15.9%

It should not be necessary to require this much math to figure out what is in your dog’s food. But there are no regulations for companies to have understandable labels. So until then, happy calculating! I hope this has helped.

~Dr Ken Tudor

The Dog Dietitian

Let us know what you think:

~Dr Ken Tudor

THE DOG DIETITIAN

Homemade Dog Food Recipes and Supplements

 

There are 2 comments

Please Share Your Thoughts!

Fill in your details below or click an icon to log in:

WordPress.com Logo

You are commenting using your WordPress.com account. Log Out / Change )

Twitter picture

You are commenting using your Twitter account. Log Out / Change )

Facebook photo

You are commenting using your Facebook account. Log Out / Change )

Google+ photo

You are commenting using your Google+ account. Log Out / Change )

Connecting to %s