Calculating calorie content in pet food

To calculate energy (caloric values) it is important to understand some of the key building blocks of nutrition and energy.

This is proteins, carbohydrates and fat.

Each of these building blocks have caloric value to them. The Furry Fitness App utilize the following caloric values in the table below:

*1) The Furry Fitness App apply what is called modified Atwater values to the calorie calculation. The simple logic behind this is that the theoretical caloric value of proteins, carbohydrates and fat does not take into account that it takes energy expenditure to digest these building blocks. To compensate for this energy expenditure the Furry Fitness app utilize modified Atwater values. A common description of this is called metabolizable energy (ME). You can read more about the calculation of energy content of foods here.

Obviously the composition of the pet food in terms of amount of proteins, fat and carbohydrates will directly influence the calorie value of the pet food you use.

Very active dogs (working dogs) such as sled dogs use pet foods that normally have a much higher value of fat in the food as opposed to normal dog or senior dog. Selecting the right composition in terms of energy value in the pet food is very important based on your dogs specific needs and activity level.

With this understanding in mind let´s go to the next step of calculating energy values for your pet food.

Unfortunately pet food manufacturers are not obliged by regulations to list the amount of carbohydrates in their pet food. Secondly the manufacturers are not obliged to list caloric value on the pet food label. This is quite baffling as this is key to be able to use pet food in a proper way to match the dogs energy requirements.

However there is a method to go about to calculate the energy in the pet food using something called a Nitrogen Free Extract (NFE) approach.

The calorie content of a food is dependent on the amounts of crude protein, crude fat, and carbohydrate in the pet food product. Carbohydrates are not measured directly, but can be estimated by calculating the “nitrogen-free extract” (or NFE) in the pet food 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. All of these components should be listed in your pet foods label under the analytical content list

The Association of American Feed Control Officials (AAFCO) has published accepted protocols for the determination of ME of dog and cat foods. Furry Fitness adhere to this approach for it´s pet food database.

Unfortunately some people believe pet food manufacturers add ash to the pet food. Read more about this misconception here.

This adult pet food has the following listed in the analytical contents list:

*2) Total kcal value in this example is per 1 000 grams/1 kg. This is the normal way of describing calorie value.

*3) The moisture content might not be listed on the analytical contents label for dry kibble food. However it is normal practice to assume the dry kibble contains 10% moisture. Furry Fitness use 10% moisture for dry kibble in the pet food database. For other types of food Furry Fitness use the manufacturer provided information in regards to moisture content.

All the pet foods listed in the Furry Fitness pet food database follow the described approach above. There might be minor deviances in caloric values applied to the pet food database vs what is listed from the pet food manufacturer themselves.

It is important to state that the NFE and caloric value in the pet food database is Furry Fitness own calculation and that these calculations adhere to the AAFCO standard. However Furry Fitness will manually review every pet food that is listed in the pet food database to safeguard it show the analytical contents right. The analytical contents is listed by the pet food manufacturer.

You will find that different pet foods have very different calorie values due the difference in amount of protein, fat and NFE (carbohydrates) that is in the pet food.