The guaranteed analysis is one of the most important things to check on a dog food label. As the name implies, it guarantees the amounts of certain nutrients, vitamins, and minerals by laboratory analysis. It’s the best way to know exactly what nutrients are going into your dog, and in what amounts.
At minimum, many state regulations require a pet food to guarantee the minimum percentages of crude protein and crude fat, and the maximum percentages of crude fiber and moisture. The “crude” term refers to the specific method of testing the product, not to the quality of the nutrient itself.”
For instance, if the microorganisms and/or healthy bacteria are not listed on the guaranteed analysis, they are not guaranteed to be alive in the food. In another example, if glucosamine and chondroitin are not listed in specific amounts on the label, you have no way of knowing how much your pet is getting.
This is particularly crucial for those owners raising large breed puppies who want to keep their dog’s protein, fat, calcium, and phosphorous at optimum levels for longer term growth.
The tricky part is understanding how the amounts are listed.
Amounts of protein, for instance, are almost always measured in a “Min” amount— as in minimum. Dog food manufacturers want to show that they reach the minimum level established by AAFCO for feeding for a specific life stage or all life stages.
Things like fiber, on the other hand, are generally reported in “Max,” as in maximum levels.
Note that the MIN levels mean that that diet has a minimum level of protein, at say 34%. It could be over that percentage. They do not guarantee the diet to stop at 34%. If it stopped at 34% every time, it would be listed as a maximum. Basically, this means that they do not calculate the percentage of these minerals beyond that specific amount.
With this in mind, be extra attentive while reading the guaranteed analysis. If you’re looking for a food with 5% fiber, and you buy a food with 5% Max listed on the label, you may actually be getting less than 5% fiber in the bag. Anything out of the bounds of the the guaranteed analysis cannot be certain.