Calories and Energetic Balance (Continued)

It is important that all animals meet their energetic requirements. A balance is obtained when energy intake is equal to the energy used. When this happens, the body is neither putting on weight (as fat), nor losing weight. In some circumstances, it is important that energy intake exceed expenditure. These are times when the animal needs to the extra energy for the development of new tissues, such as when an animal is growing, or pregnant. This is referred to as a positive energy balance. When an animal eats less than they expend, they will lose fat, a process known as negative energy balance. Many factors are needed to determine the daily caloric intake (or quantity of food) required by a pet. This requirement can be broken down into four major components, known as basal metabolic rate, voluntary muscle activity, dietary thermogenesis and adaptive thermogenesis.

  1. The basal metabolic rate determines the number of calories required to run the bodies systems if the animal is completely at rest. This is the largest portion of the energetic expenditure of your pet, up to 75%. BMR can be quite variable based on age, sex, body composition, etc.

  2. ]Voluntary muscle activity would be body movement, such as scratching an ear, barking, or going for a walk. This can comprise up to 30% of an average pet’s total energy expenditure, depending on the size of the animal, and the duration/intensity of the activity.

  3. Dietary thermogenesis is a term that refers to the heat produced during and following eating.  When food is ingested, it is required that heat be produced as a result of the digestion, absorption, metabolism and storage processes. This comprises about 10% of total energy expenditure in pets.

  4. Adaptive thermogenesis refers to additional energy expenditure that is not explained by the digestion process. It refers to additional heat production in relation to environmental stresses, such as room temperature, emotional stressors.

In many cases, people rely solely on the recommended feeding guidelines provided on pet food labels.  While this is a useful tool, it may not be accurate for all cats and dogs. Fortunately, there are easy ways to calculate an estimated energy requirement for dogs and cats at different lifestages.

For example, the National Research Council (NRC) released the following calculations for estimates of caloric energy requirements for dogs in 2006.

Inactive Adult Dogs for Maintenance
ME requirement = 95 x Weight (kg)0.75

Active Adult Dogs for Maintenance
ME requirement = 130 x Weight (kg)0.75

Let’s say you have a 20 kg adult golden retriever. If this dog spent most of its day lounging inside, it would require:

ME = 95 x 20kg0.75
ME = 898.5 kcal/day

If the same dog spent several hours running around on a farm, it would require a higher calorie intake, therefore the other equation might be more applicable:

ME = 130 x 20kg0.75
ME = 1229.5 kcal/day

How might a pet parent use this to better feed their pet? You can then use the calculated energy listed on a pet food label to personalize how much your pet should be eating! Let’s combine our two examples provided above. Let’s say we have a 20kg golden retriever that is not very active. Let’s say we are feeding it the food provided in the last exercise on calculating ME. In that food we have an energy density of 3580 kcal/kg.

From this information we can calculate the quantity of food in kilograms that your pet needs in a day.

Energetic requirement
(kcal/day) in ME

898.5 kcal/day                               ÷

Energy density

3580 kcal/kg

required (kg)

= 0.25 kg

Oftentimes, companies will provide the weight of food per cup, and from there you can calculate the number of cups required for your inactive dog! 

Keep in mind different lifestages might have different caloric needs. We’ll be doing a blog post on this topic that applies to numerous lifestages in both dogs and cats. But for now, you get the idea of how one feeding guideline might not be suitable for all dogs or cats at all activity levels and ages