Deciphering pet food labels: What you canand cannotlearn from them

A label might seem like a good place to look when evaluating the nutritional value of a pet food. Though it is a starting point, what you can actually glean about the contents of the bag or can based on the information printed on the packaging is paltry, according to Angela Rollins, DVM, PhD, DACVN, of the University of Tennessee.

In a recent session at a Fetch dvm360 conference, Dr. Rollins said assessing the quality of a pet food from the label is nearly impossible. The guaranteed analysis provides no information about the quality or digestibility of the diet, and you can also get very little information from an ingredient list. In her session, she reviewed the required parts of a pet food label, listing the caveats she and her nutritionist colleagues wish practitioners and pet owners were aware of-and there are a lot of them. In fact, by the time the lecture was over, it was clear that pet food labels are inadequate for judging the quality of a food. Here's why, and some advice about gathering the information you need about a pet food in order to recommend it to your clients.

AAFCO: What they do and don't do

The Association of American Feed Control Officials (AAFCO) establishes the regulations and policies for pet food. State feed control officials and the Food and Drug Administration (FDA) are in charge of maintaining the safety and quality of pet foods within the United States, and the United States Department of Agriculture (USDA) regulates the processing of animals for slaughter and meat.

Per the AAFCO and FDA labeling requirements, pet food packaging must contain the following components:

• The product name and brand name (on the principal display panel)

• The animal species that the food is intended to feed (on the principal display panel)

• A quantity statement (on the principal display panel)

• A guaranteed analysis, including the minimum percentage of crude protein, minimum percentage of crude fat, maximum percentage of crude fiber and maximum percentage of moisture

• An ingredient statement, with the ingredients listed in descending order by weight

• A nutritional adequacy statement

• Feeding directions

• Statement of caloric content, given in terms of metabolizable energy or as fed basis as kcal/kg and kcal per familiar household measure (such as a cup, can, treat or piece)

• Name and address of the manufacturer or distributor

Although AAFCO sets the nutritional standards and model regulations for the pet food industry, the organization does not have any legal authority over the formulation and manufacturing of pet food. Dr. Rollins says, “Legally, they can't really do anything. They are just setting out guidelines for pet food companies to follow.” She says the FDA also has some labeling requirements, but they usually get involved only when a pet food company makes health claims about a food. The USDA regulates the ingredients that go into the pet foods. “So they're going to make sure that the beef (or other meat) going into a pet food is safe, wholesome and OK for consumption. And they're going to inspect research facilities involved in the pet food manufacturing process, such as colonies of dogs used in feeding trials.” She says it's the state departments of agriculture that actually enforce animal food regulations.

The principal display panel

The front of the pet food package contains the principal display panel. “It really has very little nutritional information on there,” Dr. Rollins says. Label requirements: the manufacturer's name, the name of the brand and the product name. “There has to be what's called a designator, which is just which animal the food is supposed to be fed to,” says Dr. Rollins. “It's got to tell you what species and the life stage that it's meant for. And then it's going to tell you the quantity of the food. Not a whole lot there. You can see if it's dog food or cat food, but that's probably the most you're getting out of the front panel.”

The information panel

On the back or side of the package is the information panel, which contains the ingredient list, guaranteed analysis, a nutritional adequacy statement, feeding guidelines, a statement of caloric content, a UPC code, and the name and address of the manufacturer, packer or distributor of the food.

The ingredient list, with some definitions

The ingredient list lists what into goes the recipe, listed in descending order by weight. “It tells you the added ingredients, but it doesn't necessarily tell you all of the nutrients the food contains.” Knowing the ingredients are listed by weight, Dr. Rollins asks if you wanted to make meat your first ingredient, would you use a wet-weight kind of chicken meat or a chicken meal that's like a dry powder? “You'd choose the wet-weight meat, right? Would you use one source of protein, or would you use multiple sources of protein? You'd use one, because you would want to have a lot of heavy chicken. Would you use one carbohydrate source or multiple carbohydrate sources? Multiple carbohydrate sources, so that way not one of your carbohydrate sources is going to be heavy enough to make it to the top of the ingredient list.” She explains that it is fairly easy to manipulate the recipe to get meat to the top of the ingredient list. But it doesn't necessarily mean that the food has more protein because meat is the first ingredient.

What about those by-products? Dr. Rollins explains why she doesn't object to seeing by-products in an ingredient list. “AAFCO defines ‘poultry by-product meal' as the ground, rendered clean parts of the carcass, such as the necks, feet, undeveloped eggs and intestines,” she says. “It excludes feathers. ‘Meat by-products' are the non-rendered clean parts, other than meat from slaughtered mammals. In the pet food industry, mammals are pretty much going to be beef, goat, sheep or pigs.” The meat is going to include parts such as lungs, spleen, kidney, brain, livers, bone, fatty tissue, stomachs and intestines. The stomachs, rumens and intestines are freed of their contents so they do not contain fecal matter. The by-products do not include hair, horn, teeth and hoofs. “A lot of these by-products are actually some of the most nutritious parts of a carcass,” she says. “There are a lot more vitamins and minerals in organ meat than there is in skeletal muscle meat.”

Dr. Rollins does say, however, that by-products can vary greatly in their quality. By-products that are from liver, spleen and kidney are of a much better quality than are by-products from mostly fatty tissue and parts that do not contain many vitamins and minerals. “So, by-products can vary tremendously in quality, but you can't tell that from a pet food label. It just says ‘by-product.'”

Dr. Rollins goes on to give a definition of “beef meat” as “the clean flesh derived from slaughtered cattle, limited to the parts of the striated muscle that are found in the tongue, heart, diaphragm and esophagus.” She continues, “I bring this up because when you see ‘beef meat,' it doesn't mean that the pet is getting a T-bone steak. That's not what's going to be in pet food. It's going to be beef tongue or beef diaphragm. There's nothing wrong with that; it's not harmful. But it's not necessarily what your consumer thinks it is.”

Meat and bone meal is created by boiling meat or bone to take the fat out of it and then drying the end product. In terms of amino acid composition, meat meal, chicken meal and beef meal are equivalent to a wet-weight protein source. “We nutritionists think more about nutrients and less about ingredients,” says Dr. Rollins. “So, from a nutrient perspective, I don't have a problem with meal because I know it's going to have the same amino acid composition to it.”

“Animal digest (another thing often listed on ingredient lists) sounds a little icky, but dogs and cat like it,” Dr. Rollins says. To create digest, manufacturers chemically or enzymatically hydrolyze meats to liquefy them, and then the liquid is sprayed on the outside of a kibble as a palatant.

One last nugget of advice from Dr. Rollins on the ingredient list: “If you have an ingredient that you want to spend money on and it comes near or after salt on the list, don't spend your money on that food. It's like fairy dust because salt makes up a very, very small percentage of the food. If the ingredient is second or third on the ingredient list, great! Spend your money on that food. But if you're spending money on an ingredient that's near salt, it's a waste of money. It's in there for marketing.”

Guaranteed analysis

The guaranteed analysis includes state legal tolerance levels. “These are not the actual concentrations of the nutrients, but they're just minimums and maximums. Also, the guaranteed analysis lists only four of the more than 35 different required nutrients for dogs and cats. It tells you almost nothing. It's just a really, really poor indicator for nutritional value,” says Dr. Rollins. She goes on, “Does a guaranteed analysis tell you if the food is actually able to be digested? No. Does it tell you if the pet will actually eat the food, or if it's acceptable? No. Does it tell you if the ingredients are bioavailable, that the pet can actually utilize the protein source that's in there? It tells you nothing about any of that.”

The guaranteed analysis can give you a rough idea of the protein or fat content of the diet. “So if you're looking for a food for a patient with pancreatitis, you can at least say, ‘Oh, that's really high in fat,' or ‘That might not be too bad.' But beyond that the guaranteed analysis is pretty well worthless,” she says.

You perhaps have used calculations based on the guaranteed analysis to compare foods, but there is now a better way to compare foods, since AAFCO now requires the label to include the food's caloric content. Dr. Rollins says it's best to calculate nutrients on an energy basis, based on the calories contained in the food.

Doing the math: Example calcularion of nutrient content on an energy basis

Now that AAFCO requires caloric content to be printed on labels, you can calculate the content of any single nutrient on an energy basis, based on the calories in the food. This makes it possible to compare apples to apples when it comes to nutrient content.

As an example, Dr. Rollins wanted to compare the calcium content of these two foods:

Food 1

Food 2

4,406 calories/kg 3,309 calories/kg Calcium 1.37% Calcium 1.48%

“For the first food, I know my caloric density is 4,406 calories/kg. If the food contains 1.37% calcium, that would be 13.7 g of calcium/kg of food. We know that we have 13.7 g of calcium per 4,406 calories. What I want to know is how many grams of calcium there are per 1,000 calories, because that's a standard value in many product guides.”

The proportion to solve for grams of calcium per 1,000 calories is: 13.7 x 1,000 = 4,406x

So, x = 3.11 g calcium/1,000 calories

For Food 2, the proportion is: 14.8 x ?1,000 = 3,309x

So, x = 4.47 g calcium/1,000 calories

“So, although initially, these foods appeared to have a similar calcium content, the calculation actually shows they have quite a bit of difference,” says Dr. Rollins. “Really the best way to do nutrient comparisons between different diets is to do it on this caloric basis.”

Nutritional adequacy statement

The nutritional adequacy statement is “a little helpful, but it's not that helpful,” says Dr. Rollins. “It should tell you if the food is meant for a dog or a cat. It's going to tell you the life stage, whether it's meant for growth, maintenance, reproduction, all life stages, things like that. It should also tell you the validation method used.” The statement helps the consumer know whether the food is complete and balanced nutritionally.

A nutritional adequacy statement can be determined in one of three ways:

• The product can undergo an AAFCO feeding trial with live animals for the intended life stage. This means the product has been fed to dogs or cats for one or more life stages under strict guidelines and found to meet a minimal standard.

• The product can be formulated to meet the nutrient requirements for the intended life stage established by the AAFCO nutrient profile. This means the nutrient profiles were calculated from the ingredient list or a chemical analysis of the food was done and compared with the AAFCO profiles for the species and life stage or stages.

• The product is nutritionally similar to a sister product that underwent an AAFCO feeding protocol for the intended life stage. With this method, a food uses the same nutritional adequacy statement as a product that has completed an AAFCO feeding trial.

“We traditionally think of the feeding trial being the gold standard. And it is good to do a feeding trial,” says Dr. Rollins. “But the issue with a feeding trial is that it's really easy to pass. They're just not that stringent. So, yes, a feeding trial is probably the best we have as far as evaluating whether a food is a good food or not. But it's still not that hard and not that great. I wouldn't necessarily say a food is optimal because it passed a feeding trial. It's adequate because it passed a feeding trial.” She also points out that smaller companies might not have the resources, such as their own colony of animals or the research facilities, to perform feeding trials. She also points out that some companies do a feeding trial on one product but then use the data from that feeding trial for a sister product. “And they say it's been through an AAFCO feeding trial even though it hasn't, because there's a sister product, a similar product, that did go through a feeding trial.”

When a food is formulated to meet the nutrition requirements of the intended life stage but has not undergone a feeding trial, it will have this kind of language on the label: “_______ is formulated to meet the nutritional levels established by the AAFCO Dog (or Cat) Food Nutrient Profiles for _______.” If the food has undergone a feeding trial, it will have this kind of language: “Animal feeding tests using AAFCO procedures substantiate that _______ provides complete and balanced nutrition for _______.” If the food is a sister product of a food that has undergone a feeding trial, the language will be like this: “_______ provides complete and balanced nutrition for _______ and is comparable to a product which has been substantiated using AAFCO feeding tests.” (For all of these examples, the first blank is the product name and the second blank states the life stage the product is intended for.)

Some foods will have a nutritional adequacy statement that states “For supplemental feeding” or “For intermittent feeding only.” Dr. Rollins says, “That implies it is not complete and balanced. However, a lot of our therapeutic diets say ‘For intermittent use' or ‘For use under veterinary supervision.' That's because, for example, a renal diet is below the AAFCO recommendation for phosphorus. We want it to be below the AAFCO recommendation for phosphorus. So, just because a food says it is for supplemental, intermittent feeding, doesn't mean that it's a bad diet. That's why therapeutic diets are for use under veterinary care.”

Some chews and bones are exempt from AAFCO label requirements unless the manufacturer makes a claim of nutritional value on the label. However, treats must still meet FDA label requirements, including the name and address of the manufacturer or distributor, product identification and a listing of the ingredients by weight. Other types of commercial treats must state that the product is a treat or snack on the principal display panel.

Although there are many limitations, the nutritional adequacy statement is probably the best way to assess a food's quality based on the label alone. This statement ensures that if this product is the sole source of nutrition, it will adequately sustain an animal during the life stages listed.

Feeding recommendations

Dr. Rollins says the feeding recommendations listed on pet food labels often overestimate how much a pet actually needs to eat. “These recommendations tend to be too high,”. That is why she encourages practitioners to take the time to calculate what a patient should actually be eating and give the owner specific recommendations for feeding the pet. She says that's what pet owners want. “They want the veterinarian to make nutritional recommendations. So you can look at how many calories are in a food and tell the owner how much of that food to feed their pet each day.”

Doing the math: Calculating daily energy requirements for a pet

To determine how many calories a pet should be consuming each day, you first need to calculate its resting energy requirement (RER). You do that based on what the patient should weigh, in kilograms. “If they're overweight, you don't want to use the overweight weight. You want to use the ideal weight,” says Dr. Rollins.

RER = 70 x BWkg0.75

“From there,” she says, “you will multiply the resting energy requirement by a life stage factor based on their activity level, their breed, and whether they're neutered or intact.”

Daily energy needs = Life Stage Factor x RER

Life stage

Canine factor

Feline factor

Adult, intact 1.8 1.4 Neutered 1.6 1.2 Senior 1.4 1.1 Obese prone 1.2-1.4 1-1.2 Weight loss 0.8-1.2 0.8-1 Growth 2-3 2-5 Gestation 1-3 1.6-2 Lactation 4-8 2-6

Example calculation:

For a 5-kg cat, the RER would be 70 x 50.75= 70 x 3.34 = 234 kcal/day. If the cat was a neutered male, you would take the 234 kcal/day RER and multiply that by a life stage factor of 1.2 to estimate the cat's daily energy needs: 234 x 1.2 = 280 kcal/day.

Good questions for practitioners to ask pet food manufacturers

Another method for assessing the quality of a pet food is to call or email the company and ask a few simple questions. Dr. Rollins recommends asking these questions, taken from the World Small Animal Veterinary Association's nutrition toolkit:

Can your company provide an average/typical nutrient analysis for the dog or cat food? Or at least for their lead product? This is different from the guaranteed analysis, which includes only minimums and maximums for just a few nutrients.

Does your company employ a full-time qualified nutritionist? Do you have a veterinary nutritionist or PhD-level animal nutritionist on staff at your company? And can I consult with them, especially about the use of therapeutic diets in my patients?

Who formulated the company's foods and what are his or her credentials?

Are your diets tested using AAFCO feeding trials or by formulation to meet AAFCO nutrient profiles? If the latter, do the diets meet AAFCO nutrient profiles by formulation or by analysis of the finished product?

Where are the diets produced and manufactured?

What specific quality control measures does the company use to assure the consistency and quality of the ingredients and the end product?

According to Dr. Rollins, companies should freely provide the information above. She believes that those who refuse to discuss the questions or provide nutrient profiles should be viewed with suspicion. “Are they forthcoming? Are they organized? Do they get back to you with answers to your questions?” she asks. “By talking with the company representative, you can get a feel for whether the company is reputable, or if they seem like they are unorganized and don't know what they're doing.”

Manufacturing considerations

As far as pet food manufacturing practices, Dr. Rollins recommends looking for companies that use good ingredients and that have good processing practices and good quality control. Ask where they source their raw ingredients. “They should have very specific directions and requirements for suppliers, for things like the nutrient composition and the purity,” says Dr. Rollins. Manufacturers also need to store their ingredients properly in climate-controlled facilities. “And they should have both internal and external auditing of their facilities to make sure they are living up to very strict standards,” she says. They should keep a close eye on their suppliers and vendors, testing shipments of ingredients even before they are unloaded from trucks. In addition, the final product should be consistent in its appearance, and the packaging should have integrity. “You don't want a lot of dents in the cans or fat leaking through bags,” she says.

How to choose a pet food without relying on a label

Looking at all these factors you have to consider, assessing the quality of a pet food from the label is nearly impossible. So how can you evaluate the quality of a food? Instead of relying on the label-which you can't-Dr. Rollins says you should pick up the phone and call the company or email them. (See sidebars: “Good questions for practitioners to ask pet food manufacturers” and “Other online resources for practitioners and owners to help assess pet foods”)

“When you're trying to pick a brand of pet food to recommend, keep in mind that every pet is different,” says Dr. Rollins. “So you're going to choose it based on the pet's needs first.”

And remember that pet food labels really tell you very little. “In general, I rely a lot on a company's reputation,” says Dr. Rollins. “I tend to go more with reputable companies because I know safety is Priority 1. Maybe the small boutique companies really are doing a fantastic job. I just don't know enough about their safety. Whereas, with the bigger companies, I just feel comfortable that they're going to be safe.”

When Dr. Rollins is thinking about what food to recommend for a particular patient, she likes to ask the client where they you want to buy the food. “That question can tell you a lot about their price point, and it's not judgmental,” says Dr. Rollins. “If they say, ‘I'm probably going to buy it at the grocery store,' then that gives you a level of foods you know are at the grocery store.” The same thing is true if they plan to shop at a pet store or a boutique-type store. She says you can buy a middle-of-the-road food that will be fine and not have to spend a lot of money, but she does recommend that clients avoid generic or grocery-store-brand pet foods because those are of such low quality. “They do what's called least-cost formulations,” she says. “They basically buy the cheapest ingredients at the moment to make the cheapest product they can possibly make.”

Other online resources for practitioners and owners to help assess pet foods

Another resource for pet owners is AAFCO's consumer-friendly website, which addresses pet owner questions related to pet food. There is a section on “Reading Labels” that discusses all of the components required on a pet food package label.

The World Small Animal Veterinary Association's Global Nutrition Committee created a downloadable handout with their recommendations to consider when selecting pet foods. Their recommendations include most of the same questions for manufacturers that Dr. Rollins suggested in the sidebar above.

The Clinical Nutrition Service at the Cummings School of Veterinary Medicine at Tufts University maintains a helpful, engaging website called Petfoodology that contains articles and advice for practitioners and pet owners, including dozens of articles on finding the best food for a pet and on pet nutrition basics.

Dr. Rollins points out that there have been recent improvements in the safety and quality control standards for pet food manufacturing. The FDA Food Safety Modernization Act (FSMA) of January 2011 was aimed at preventing food-borne illness from human and animal foods sold in the United States. For animal food, this law requires manufacturers to use current good manufacturing practices (cGMPs) and preventive controls. While most manufacturers were to be in compliance by September 2017, some smaller companies have until September 2020 to meet all of the regulatory standards. In addition, Dr. Rollins says, “AAFCO is making a push now to make pet food labels with nutritional display panels similar to human foods.” She acknowledges that it takes time for AAFCO to implement changes, but says, “Maybe in 10 years we'll have that on pet foods. And that would make thing much easier for everyone to look at and assess things.”

Speaker bio: Angela Witzel Rollins, DVM, PhD, DACVN is a clinical associate professor in Small Animal Clinical Sciences at the University of Tennessee College of Veterinary Medicine. Her research focuses primarily on obesity physiology, prevention and treatment in dogs and cats.