How do I Calculate the Calorie Content?
Where a label calorie content statement is required or simply desirable, it may be calculated from the same proximate analysis data used for setting guarantees. Unlike guarantees, it is NOT declared as a minimum or a maximum, but as an average based on multiple proximate analysis data.
The calorie content of a food is dependent on the amounts of crude protein, crude fat, and carbohydrate in the product. Carbohydrates are not measured directly, but can be estimated by calculating the “nitrogen-free extract” (or NFE) in the product. This is determined simply by subtracting the average of each of the other components (percent crude protein, crude fat, crude fiber, moisture AND ash) from 100 [see the following example].
The next step is to multiply each of the average percentages for the calorie-containing nutrients by the appropriate “modified Atwater” value. Protein and carbohydrate are assigned a value of 3.5. Fat is much more calorie dense, hence has a value of 8.5. The results of the three calculations are added. Then, to convert the answer to kcal/kg (the units required on the label), the sum is multiplied by 10.
Some lab reports include calorie values. However, this information is only useful and can be used in lieu of the above calculations if the lab is familiar with calorie calculations specifically for pet foods. A laboratory that primarily analyzes human foods will not use the same modified Atwater values in its calculations, hence will give you an inaccurate calorie content number.
Also useful information is the number of calories per treat or cup of product. First needed is the weight of a single treat or a cup of product in grams. Dividing the kcal/kg value as determined above by 1000 converts it to kcal per gram. Then, multiplying by the number of grams per treat or cup gives you the calories per treat or cup.
Example: Calculating calorie content from proximate analysis data
Nitrogen-Free Extract = 100 – (crude protein + crude fat + crude fiber + moisture + ash)
Metabolizable Energy = [(3.5 X crude protein) + (8.5 X crude fat) + (3.5 X nitrogen-free extract)] X 10
Calorie content (ME)= 3688 kcal/kg; If a treat weighs 10 grams apiece, the calories per treat = 3688/1000 X 10 = 36.9 kcal/treat; If a food weighs 120 grams per cup, the calories per cup = 3688/1000 X 120 = 442.6 kcal/cup
For instance, what exactly does it mean when the label states that the food meets the AAFCO standards for "maintenance" and "growth and maintenance" and "all life stages"?
All pet foods, including snacks, treats, cookies, chews, rawhides, supplements, and complete and balanced products are regulated by the states under the state's feed law and pet food regulations, if the state has adopted such legislation. Under most state pet food regulations, there are four categories of pet foods, and they are:
- Snacks and Treats - If the product is a snack or treat, you must see those words on the front of the product label. For snacks or treats, the manufacturer still has to label their products with all of the required information, but no other nutritional standards apply.
- Intermittent or Supplemental Pet Foods - For products that do not contain all the nutrients the pet needs but are intended to be fed in addition to a complete diet, the label must bear a statement verbatim: "This product is intended for "intermittent or supplemental feeding only." Some examples of these products are gravies and meat chunks to be added to dry kibble, "appetizers", and flavored waters. Some snacks and treats may also bear this label statement.
- Complete and Balanced Pet Foods: Complete and balanced pet foods are those that are intended to be the sole diet of the pet (except for water) and provide all nutrients that we know the pet needs for its specific life stage. You may see similar types of claims on the label such as "Total Nutrition", "100% Nutritious" and "Balanced Diet." If intended for specific life stages, those must be indicated in the claim, otherwise it is assumed for all life stages.
- Special Purpose Products: Products that may not fit into any of the categories above, but are intended for a specific purpose, must be labeled to clearly show the intent and use of the product, such as "Orphan Puppy Milk Replacer."
What are the nutritional requirements for complete and balanced pet foods?
While it is the state that regulates all animal feed and pet food, AAFCO has determined the nutritional standards for complete and balanced pet food. Please know that AAFCO does not regulate, test, approve or certify pet foods in any way. AAFCO establishes the standards, and it is the state's AND the pet food company's responsibility to ensure that complete and balanced pet foods meet AAFCO's nutritional standards.
- The pet food must contain every nutrient that we know the pet needs as specified in the AAFCO Dog Food (or Cat Food) Nutrient Profiles. The nutrients listed in the AAFCO Nutrient Profiles are based on the nutritional recommendations of the National Research Council (NRC) for dogs and cats. The NRC recommendations are based upon the nutritional needs of the pet using purified diets. AAFCO has translated these absolute dietary needs of the pet into the nutrients and levels that should be in pet FOOD.
AAFCO's Nutrient Profiles are broken down into two categories (or life stages) - Growth & Reproduction and Adult Maintenance. If the pet food meets all of the nutrient requirements of both Growth & Reproduction AND Adult Maintenance as listed in the AAFCO Nutrient Profiles, then that pet food would be considered to be nutritionally adequate for "all life stages."
If the pet food meets the nutrient requirements of the AAFCO Nutrient Profiles, the label must bear the following statement:
"(Name of product) is formulated to meet the nutritional levels established by the AAFCO Dog (or Cat) Food Nutrient Profiles for ________." (Blank is to be completed by using the stage or stages of the pet’s life such as gestation, lactation, growth, maintenance, or the words "All Life Stages.")
While the AAFCO Nutrient Profiles list the "minimum" levels (and some maximum levels), the pet food company can formulate and market their products for a specific life stage - provided the nutritional profile of the pet food still meets the levels specified in the appropriate AAFCO Nutrient Profile.
- The second option is for the pet food to pass an animal feeding trial using procedures developed by AAFCO in the AAFCO Dog and Cat Food Feeding Protocols. The AAFCO Protocols mandate factors such as the length of the trial, the number of animals, the feeding procedures and the diagnostic tests which determine if the feeding trial was successful. For products that pass an animal feeding trial using the AAFCO Feeding Protocols, the label must bear the following statement:
"Animal feeding tests using AAFCO procedures substantiate that (product name) provides complete and balanced nutrition for _________." (Blank is to be completed by using the stage or stages of the pet's life tested such as gestation, lactation, growth, maintenance or the words "All Life Stages".)
This method can be used by companies to formulate products that may or may not meet the AAFCO Nutrient Profiles. Examples are those products used by the veterinarian in their treatment of certain conditions where the pet's diet must be lower in protein, sodium, etc.
- A third option is based on establishment of "product families". The lead product member must pass the feeding trial, and the other members of the family be deemed nutritionally similar to the lead product by meeting specified nutrient and calorie criteria. Most often, the statement for the product family members are the same as in number (2) above.
The AAFCO Dog Food (and Cat Food) Nutrient Profiles, the AAFCO Dog and Cat Food Feeding Protocols and the product family criteria are described in detail in the AAFCO Official Publication (OP).
How can I calculate the total crude protein percentage in certain pet food?
AAFCO does not have a "pet food nutrient calculator". That means you must calculate the required protein yourself. Let's work through the calculations.
AAFCO has approved the AAFCO Dog Food Nutrient Profiles that determines the minimum (and some maximum) levels of nutrients in complete and balanced pet food based upon the particular life stage of the pet. The minimum levels for Crude Protein are:
For Growth and Reproduction diets (for puppies and pregnant/nursing dogs), the minimum level of Crude Protein on a DRY MATTER basis (which means all the moisture in the dog food has been removed) is 22.0%.
For Adult Maintenance diets, the minimum level of Crude Protein on a DRY MATTER basis is 18.0%.
Guarantees on pet food labels are listed on an "AS FED" or "AS IS" basis, and all pet foods vary in moisture content. You must correct for the moisture so that you can determine the required level of crude protein for your pet food based upon its moisture guarantee. You can adjust the AAFCO Nutrient Profile level by doing the following:
- First, determine the DRY Matter of your dog food, which is 100% minus the % moisture guarantee, and then divide that number by 100.
For a canned dog food that guarantees 75% Moisture, the Dry Matter is 100% - 75% = 25% Dry Matter.
For a dry dog food that guarantees 10% Moisture, the Dry Matter is 100% - 10% = 50% / 100 = 0.90 Dry Matter.
- Then, multiply the AAFCO Nutrient Profile value for Crude Protein by the Dry Matter that you calculated for your specific dog food. For the two examples noted above, the values are:
If we tried to have a table for all possible moisture levels - for dry food, for canned food and for semi-moist food - the number of tables would be overwhelming. So, we make one table and then calculate to the appropriate level of moisture in the pet food.
Are claims such as "low fat" and "high protein" allowed on pet food labels?
AAFCO has approved a model feed law and regulations that the states are encouraged to adopt as their own state requirements. One of these regulations is the AAFCO Model Regulations for Pet Food and Specialty Pet Food. Pet foods are foods for dogs and cats, and specialty pet foods are foods for pets normally maintained in a cage or tank, such as hamsters, pet birds, and aquarium fish. About half of the states have adopted some version of these AAFCO pet food regulations.
The AAFCO Model Pet Food Regulations contain requirements for claims regarding calorie and fat content. Please check the section for Model Pet Food Regulation PF10. Descriptive terms can be found starting on page 141 of the 2010 Official Publication. In this section, Regulation PF10(a) covers the requirements for calorie claims stating "Light", "Lite", "Low Calorie", "Less", or "Reduced Calories". Regulation PF10(b) covers the requirements for fat clams stating "Lean" and "Low Fat" and "Less" or "Reduced Fat".
The AAFCO model regulations do not contain any specific requirements for other claims such as "high protein", "low sodium", etc., only that these claims should not be false or misleading to the consumer. A control official may be guided by the levels of the nutrients listed in the AAFCO Dog Food (and Cat Food) Nutrient Profiles starting on page 144 of the 2010 Official Publication. The levels in the Profiles are the minimum (and some maximum) levels for all essential nutrients required in dog food and cat food. Claims for carbohydrate levels in pet foods are discouraged since at this time there is no uniform method for determining carbohydrates.