Understanding Guaranteed Analysis Levels in Dog Food
How do you compare two similar dog foods? For many people, the first instinct is to look at the guaranteed analysis levels. After all, the guaranteed analysis gives us, the consumers, concrete data making it easy to compare the nutritional values of different dog food formulas. Or does it?
While guaranteed analysis is a good starting point, there are limits to what this data can tell us.
Today, we’ll talk about what guaranteed analysis actually is, what its limitations are, and we’ll finish with some tips to help you accurately compare nutrient levels in different dog food formulas.
What Guaranteed Analysis Can and Can’t Tell Us
So what is guaranteed analysis? It is a requirement of regulatory bodies for pet food manufacturers to disclose the minimum or maximum levels of certain nutrients in their products.
Related: The Best Dog Foods Australia.
A typical guaranteed analysis will contain these four parts:
Related: How To Choose The Right Dog Food.
The levels of these nutrients must be listed. Other nutrients can be listed, and often are in higher quality dog food, but that is not a requirement. The exceptions are cases where dog food packaging features additional claims, such as “low fat” or “high in vitamin E”. In those cases, the values of the relevant nutrient must be listed.
*The AAFCO guideline has a requirement to list the maximum amount of moisture in a formula and no requirement to list metabolisable energy. The Australian standard AS5812:2017 has no requirement to list moisture levels, but instead requires ME. Read more on why this is relevant in the final section of this article.
Related: What Is the Pet Food Industry Association of Australia (PFIAA)?
Related: AAFCO vs PFIAA: Dog Food Standards Comparison Australia
But first, let’s unpack this relatively simple list:
Let’s start with this weird word. In the context of guaranteed analysis, the term "crude" refers to the method of analysis used to determine the nutrient levels in dog food. The crude analysis method provides a good general estimation of nutrient levels in dog food, but keep in mind that it’s not completely accurate.
Also, it does not provide detailed information about the specific sources or quality of those nutrients. For example, crude protein measurement does not differentiate between high quality protein derived from animal sources and lower quality plant-based proteins.
Minimums and Maximums
You’ve also probably noticed the words “minimum” and “maximum” in the guaranteed analysis, so what’s that about?
“The guaranteed analysis doesn’t give us the actual percentages of these four nutrients in the food; instead, they are listed as minimum levels (for protein and fat) or maximum levels (for fibre and moisture). There can be a lot of variation between these minimum, or maximum, values and the actual amount of that nutrient in the food.” - Dr. Lisa M. Freeman, Petfoodology (1)
If a food says, for example, 20% protein, that means 20% or more - it might be 23% or it might as well be 60%. How much is it exactly? We have no way of knowing.
Limitations of Guaranteed Analysis
To summarise, guaranteed analysis is an important requirement for dog food labelling, and it’s great for giving you a general idea about the feed. But don’t expect it to be completely accurate.
“Why don’t the pet food companies use more accurate numbers on the GA? It’s partly to make sure that the products won’t fail a test of the minimum amounts of protein and fat, and partly to account for variations in nutrient levels in their raw ingredients.” - Nancy Kerns, Whole Dog Journal (2)
These are the main limitations of guaranteed analysis:
Comparing Guaranteed Analysis Levels in Dog Foods
Now we need to elaborate on the last point. To get a better understanding of the issue, just imagine this scenario: a dry dog food bag lists 12% protein, and a can of wet dog food also lists 12%. In the first case, 12% is terribly low and you should probably not buy the food. In the case of wet food, 12% is actually pretty decent. That’s because canned food is full of water, and your dog will need to eat a much larger quantity in a single meal.
There are two ways to overcome this problem:
Dry Matter Basis
Dry matter basis calculation is a method used to compare the nutrient content of dog foods without taking into account the differences in moisture content. Since moisture can vary significantly among different types of dog food (wet, dry, semi-moist), converting the nutrient values to a dry matter basis allows for a more accurate comparison.
You’ll want to use this method when a dog food label lists the moisture percentage.
To calculate the dry matter basis, follow these steps:
Determine the moisture content: Check the guaranteed analysis or packaging of the dog food to find the moisture percentage. For instance, if the dog food has a moisture content of 10%, this means it contains 90% dry matter.
Calculate the dry matter basis for a specific nutrient: Select the nutrient you want to calculate on a dry matter basis. Let's take protein as an example.
Obtain the nutrient value: Find the percentage of the nutrient you are interested in from the guaranteed analysis. For protein, let's assume it is listed as 25%.
Divide the nutrient value by the dry matter content: Divide the nutrient value by the percentage of dry matter. In this case, divide 25 by 90 (since the dry matter content is 90%). The result is approximately 0.28.
Multiply by 100: Multiply the result from step 4 by 100 to express the dry matter basis as a percentage. In this example, 0.28 multiplied by 100 equals 28%.
The calculated value of 28% represents the protein content on a dry matter basis, allowing you to compare it directly with other dog foods that have been converted to dry matter basis using the same method.
Another way to compare dog foods is based on calories. This method might be more accurate than dry matter basis (1), but it essentially does the same thing: it takes the variability of dog food ingredients out of the equation.
When using this method, you calculate the percentage of each nutrient per 100 kcal. The formula is not too complicated, and you can find it easily online - or use this calculator.
This method is helpful for cases where the packaging does not list the percentage of moisture. You can use metabolisable energy (ME) values instead to achieve the same calculation.
As you have seen, the guaranteed analysis levels data is far from perfect, and not always accurate. But does that mean that it’s useless? Absolutely not. It still is a great way to compare dog foods, as long as we are aware of the limitations.
- Freeman, L .M. December 28, 2020. “What Is Guaranteed about the Guaranteed Analysis?”. Petfoodology. Retrieved June 13, 2023. https://vetnutrition.tufts.edu/2020/12/what-is-guaranteed-about-the-guaranteed-analysis/
- Kerns, N. April 24, 2019. “Dog Food Guaranteed Analysis: Truth on the Label”. Whole Dog Journal. Retrieved June 13, 2023. https://www.whole-dog-journal.com/food/dog-food-guaranteed-analysis-truth-on-the-label/