Pet food labels differ from human food labels in several ways – one of which is instead of the “nutrition facts” on human food labels, pet food labels have a “guaranteed analysis”. Why? Why do human food labels have “as fed” or average nutrient contents on their labels, whereas pet food labels have minimums and maximums? Well, primarily to give the pet food manufacturer more leeway to vary the contents based on cost. Many manufacturers use a “least cost” method to creating their pet food – meaning they’ll adjust the level of ingredients in order to achieve the lowest cost for the food (maximizing profit).
Now, assuming we’re all okay with that (or not), another difference is the absolute *lack* of some information on the pet food label – such as carbohydrate content. We have moisture, protein, fat, fiber… no carbohydrates. Now, we could try to figure out the carbohydrates from what we have – I mean if we know how much moisture, protein, fat, etc. there is in the food – the rest must be carbohydrates right? Well, yes and no. Let’s look at an example:
9-Lives ground chicken & tuna dinner
The label’s guaranteed analysis says: minimum 9% protein, minimum 4.5% fat, maximum 78% moisture, maximum 3.5% ash, maximum 1% fiber
Subtracting the minimums and maximums from 100%, we get 100% – 9% – 4.5% – 78% – 3.5% – 1% = 4% carbohydrates. If we then want to convert to dry matter (so we could compare this canned food to a dry food, for example), it’s 16% carbs dry matter: 4% / (100%-78%).
However, if we contact the company for as fed information (and I have), we get a very different story. I don’t have the exact numbers with me, but roughly, they were on a dry matter, “as fed” basis… so averages, not minimums or maximums:
Protein (average) – 58%
Fat (average) – 35%
Carbohydrates (average) – 6%
Note: for example, the protein dry matter average of 58% is greater than the *minimum* listed on the can of 9% / (1-78%) = 36% dry matter. That’s all that’s necessary – that they properly label the MINIMUM. Therefore, by definition, on average the can will contain more protein and more fat than what is listed.
Janet has collected “as fed” information for a large number of commercial cat foods, and she converts the numbers to a percent of calories… by converting the %’s to grams, and then grams to calories (using the assumptions she notes).
Protein = 39% calories (average)
Fat = 57% calories (average)
Carbs = 4% calories (average)
VERY different picture – not only because we’re using averages, not minimums/maximums, but also because fat has 8.5 calories/gram, much higher than protein and carbs (3.5 calories/gram).
You can’t really compare “the label math” to “as fed” information or Janet’s charts… it’s comparing apples and oranges.
Getting back to my example – 9-Lives ground chicken & tuna, something I personally do feed fosters, etc.
Ingredients: MEAT BY-PRODUCTS, CHICKEN, WATER SUFFICIENT FOR PROCESSING, FISH, POULTRY BY-PRODUCTS, CHICKEN BROTH, TUNA, GUAR GUM, SALT, POTASSIUM CHLORIDE, SODIUM TRIPOLYPHOSPHATE, TITANIUM DIOXIDE, NATURAL FLAVOR, CHOLINE CHLORIDE, CARRAGEENAN, VITAMINS (VITAMIN E SUPPLEMENT, VITAMIN A SUPPLEMENT, THIAMINE MONONITRATE, NIACIN SUPPLEMENT, D-CALCIUM PANTOTHENATE, RIBOFLAVIN SUPPLEMENT, PYRIDOXINE HYDROCHLORIDE, MENADIONE SODIUM BISULFITE COMPLEX, VITAMIN D3 SUPPLEMENT, FOLIC ACID, BIOTIN, VITAMIN B12 SUPPLEMENT), MINERALS (MAGNESIUM OXIDE, FERROUS SULFATE, ZINC OXIDE, MANGANOUS OXIDE, COPPER SULFATE, CALCIUM IODATE, SODIUM SELENITE), TAURINE, SODIUM NITRITE (TO PROMOTE COLOR RETENTION).
I see *no* grains listed, no vegetables, no fruit.. just a bit of guar gum for fiber. I think this is a perfectly acceptable low-carbohydrate canned food.
This is why I rely much more on the list of ingredients than I do either Janet’s charts *or* the guranteed analysis. Unless the very faulty labeling requirements change, it’s very hard to use the analysis for anything,
So, I read ingredients. If there’s no grains, veggies, fruit… it’s most likely low in carbohydrates. If it’s filled with grains, sweet potatoes, potatoes, etc. it’s probably not. Companies are required to list them in order by weight. It’s not a perfect system, but if you use it in conjunction with what we’ve got, it’s the best you can do.
Now, why do we even care about carbohydrates? Cats have no nutritional requirement for carbohydrates. Well, because high-carbohydrate diets have been linked to diabetes, struvite urinary stone formation, inflammatory bowel disease, obesity, and other ailments.
That’s why I am petitioning that caring pet owners contact the FDA with their comments in anticipation of an upcoming “public meeting” on pet food labeling. Specifically, I’m requesting that maximum carbohydrate content be added to pet food labels. It takes only a few minutes of your time to send in your comments, I’ve provided mine so you can just copy and paste, if you like. I hope, for all our pets’ sake, you’ll take the time to do so.
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