Written by Dr. Jill Cline, Ph.D.
Dog and cat owners have many choices when it comes to pet foods. Products are designed for pets of different ages, breed sizes, activity levels, and lifestyles. In addition, a wide variety of flavors, textures, kibble sizes and forms of food are available. Given all of these choices, it is not surprising that selecting a good pet food can be a daunting task! Here are a few tips for using information on the pet food label to help you select the best food for your pet.
Pet Food Label Regulation
Pet food labels are regulated at several levels and involve both federal and state agencies. The two most important are the Food and Drug Administration’s Center for Veterinary Medicine (CVM) and the Association of American Feed Control Officials (AAFCO). Each organization oversees particular components of the pet food label, such as ingredient terms and acceptable and non-acceptable advertising claims. The current pet food regulations require that labels of all packages and cans of commercial foods include the following five pieces of information: guaranteed analysis panel, nutritional adequacy statement, list of ingredients, feeding guidelines, and the manufacturer’s name and address.
The guaranteed analysis panel reports the food’s minimum crude protein, minimum crude fat, maximum moisture and maximum crude fiber contents. (Note: the term “crude” refers to specific laboratory methods used to measure these nutrients and does not reflect nutrient quality). The “minimum” rule for protein and fat means that the food must include at least the stated level of these nutrients and may contain more. Similarly, the “maximum” rule for moisture and fiber tell the consumer that the food may contain less than the printed amount but cannot contain more. Although not required, some manufacturers also include optional nutrient information such as magnesium (minimum percent), taurine (minimum percent), linoleic acid (minimum percent), or ash (maximum percent).
When examining the guaranteed analysis panel, large differences in moisture content between canned and dry pet foods can lead to confusion when attempting to compare nutrient levels. Because the pet food label displays nutrient levels on an “as-fed” basis, the large amount of water in canned foods causes reported nutrient levels to appear very low. Therefore, if you wish to make valid comparisons of nutrients between a canned and a dry food, it is necessary to correct for these differences in moisture content (Box 1).
Comparing Nutrient Levels in Canned and Dry Pet Foods
Dry foods contain only a small proportion of water (6 to 12 %), while canned foods can contain up to 78% water. These differences must be accounted for when comparing information provided on the guaranteed analysis panel. The following example compares a dry dog food with a guaranteed analysis of 26 % protein with a canned food that has a guaranteed analysis of 8 % protein:
Dry Dog Food (~ 8 % moisture)
Crude Protein (minimum): 26 % ÷ 0.92* = 28.26 % crude protein (dry)
Canned Dog Food (~75 % moisture)
Crude Protein (minimum): 8 % ÷ 0.25* = 32.00 % crude protein (dry)
When the moisture contents of these two products are equalized, the canned food actually has a higher protein content than the dry product. This means that, when fed, the canned food will provide a higher proportion of protein than the dry food.
* (100 – estimated moisture in food)
Just like human foods, the ingredients that are included in pet foods are listed on the label in descending order of predominance by weight. The ingredient list can provide pet owners with general information about the type of ingredients that are included in the product. However, it does not provide information about ingredient quality. For example, some premium foods with high quality, highly available ingredients have an ingredient list that is almost identical to those of foods that contain poor quality ingredients with low digestibility and nutrient availability. Because of this limitation, the ingredient list alone should never be used to compare the quality of two pet foods.
Nutritional Adequacy Statement
The nutritional adequacy statement identifies the stage of life for which the pet food is designed and describes the method used to prove that the food supplies all of a pet’s nutrient requirements for that life stage. The most common and well-known statement is the “complete and balanced for all life stages” claim. This claim signifies that the pet food will supply all of a dog or cat’s nutritional needs for all stages of life, including pregnancy, lactation, growth, and adulthood. Manufacturers also must describe the method that was used to prove nutritional completeness; either through the completion of AAFCO-sanctioned feeding trials (the most thorough method), or by stating that the food’s nutrient content was formulated to meet standard dog or cat nutrient profiles.
All dog and cat foods that carry a “complete and balanced nutrition” claim must include feeding guidelines on the label. These instructions provide pet owners with a general volume to feed based upon their pet’s body weight. This amount can be adjusted up or down in response to an individual pet’s needs. Although pet food manufacturers are not required to include information about the caloric content of the food, this information is of interest to many pet owners and can help when selecting a food for a pet’s lifestyle and activity level. For example, a sedentary adult dog will benefit from a food that has fewer calories per unit weight or volume than a food that is needed by a hard-working herding dog. If caloric information is not provided on the label, pet owners can use the values on the guaranteed analysis panel to calculate an estimate (Box 2).
Using the Guaranteed Analysis Panel to Estimate Caloric Content
The guaranteed analysis panel found on all pet food labels provides an estimate of the food’s minimum protein, minimum fat and maximum fiber and moisture percentages:
Crude protein not less than 27.0%
Crude fat not less than 16.0%
Crude fiber not more than 5.0%
Moisture not more than 8.0%
These numbers, plus a general estimate of ash (mineral content), can be used to estimate the food’s carbohydrate content:
100 % – % Protein – % Fat – % Fiber – % Ash = % Carbohydrate
100 % - 27% - 16% - 5% – 7% = 45%
These percentages can be used to calculate the total calories in 100 grams of food:
Analysis (%) X Kcal/gm
of Nutrient = Kcal/100 gm
Protein 27 X 3.5 = 94.5
Fat 16 X 8.5 = 136
Carbohydrate 45 X 3.5 = 157.5
TOTAL CALORIES = 388 kcal/100 gm
This food contains approximately 388 kcal/100 grams of food (3880 kcal/kg) or 1763 kcal/lb of food. A measuring cup portion of dry food weighs approximately 3 ounces. Using the following calculations:
1763 kcal/lb ÷ 16 oz = 110 kcal/oz
110 kcal/oz x 3 oz = 330 kcal
One cup of this food provides approximately 330 kcal.
A Few Helpful Tips for Choosing Foods
• Guaranteed analysis panel: The guaranteed analysis panel provides a rough estimate of the food’s protein, fat, fiber, and moisture content. This information can be used as a starting point for general comparisons between foods and can also be used to calculate an estimate of the food’s caloric content.
• Ingredient list: The ingredient list can provide information about the food’s primary sources of protein, carbohydrate and fat. Although this list does not reflect ingredient quality, it can be helpful in selecting a food that contains a desired ingredient or in ruling out a food that includes an ingredient that the owner wishes to avoid.
• Complete and balanced nutrition: When choosing a food for daily and regular feeding, look for a “complete and balanced” claim that includes your pet’s life stage (i.e. puppy/kitten, adult maintenance or “all life stages”). If the food does not state that it provides complete and balanced nutrition, the label should indicate for “intermittent feeding only” or state that the product should be fed only as a snack.
• Nutritional adequacy statement: A nutritional adequacy statement that includes the words “animal feeding tests” or “feeding studies” means that the food was tested using the highest standard; AAFCO feeding protocols. Here is an example: “AAFCO feeding studies were conducted to substantiate that (brand) provides complete and balanced nutrition for (life stages).”
• Name and address of manufacturer: In addition to their location, reputable manufacturers also include a toll-free phone number and web site for customer service on their product label. Use this number to obtain additional information or to gain answers to your questions about a food.
• Listen to Your Pet! Above all else, every animal is an individual – both in terms of personality, and also with respect to energy needs, activity level and lifestyle. Just like people, dogs and cats have specific likes and dislikes regarding the taste and texture of food. Select a high quality food that your pet finds appealing and satisfying. When fed, the food should result in normal gastrointestinal tract functioning and produce regular, firm, and well formed stools. The food should support wellness, healthy skin and coat condition, and proper body physique and muscle tone.