Canine Caloric Needs

In my experience most people don’t really think about their pet’s caloric needs much. Most people just start feeding a certain amount (usually what is recommended on the bag / container) then adjust how much they are feeding if their vet tells them to. Now this isn’t really a bad way of doing things, but I would argue that understanding your dog’s caloric needs is probably a bit better, and can actually help you effectively choose which diet is most appropriate for them to eat.

Estimating Caloric Needs of Your Dog

There are several ways to estimate caloric needs for dogs. What you need to understand is that ultimately all these calculations are estimates meaning that actual caloric can vary quite a bit. Now you might be wondering why calculation or estimate needs at all? That is a great question. And there are two main answers - first is that when we don’t know what our needs are, having an estimate is a place to start. The second reason is that when we formulate food, AAFCO nutrient profiles are meant to provide a complete and balanced diet as a certain amount of calories consumed (this is RER x 1.6). So if your dog is consuming less than this amount, this means your dog needs a diet specifically formulated for low-calorie feeding. And if feeding a highly restricted amount of calories (below RER) you dog likely needs a prescription weight loss formula, or homemade diet formulated for restricted caloric feeding.

Calculating Base Caloric Requirements

The first step of calculating or estimating your dog’s caloric needs is by calculating their resting energy requirements (RER).

  • RER = (weight in kg) ^0.75 x 70

The resting energy requirement, or RER is typically used for dogs undergoing weight loss, or that maintain their healthy weight on a very low amount of calories. This an happen in senior dogs that are obese prone - think of a 9yr old Golden Retriever. Knowing your dog’s base caloric requirements can be useful for comparison purposes - if at any time you realize your dog is eating at or below resting energy requirements, your pup either needs a special restricted caloric feeding diet, or you might want to do some diagnostics with your vet to check to see if your dog has a medical condition like hypothyroidism that changes metabolism.

Calculating Caloric Needs for Active vs Inactive Dogs

There are two main ways to calculate or estimate caloric needs - one is by using the NRC method, which uses a different cofactor instead of the “70” in the RER calculation. And the second is by multiplying our basic caloric calculation (RER) by a k-factor. Neither of these calculations is “wrong”, it mostly just comes down to personal preference.

NRC Method for Calculating Caloric Requirements:

  • For Dogs who have low to moderate activity (30-1hr) = (weight in kg) ^0.75 x 95

  • For Dogs who have moderate to higher activity (1-2 hrs) = (weight in kg) ^0.75 x 130

K Factor Method for Calculating Caloric Requirements:

  • Dogs who are obese-prone, overweight or have very low activity = [(weight in kg) ^0.75 x 70] x 0.8 to 1.2

  • Dogs who are lightly active (most urban dogs & senior dogs) = [(weight in kg) ^0.75 x 70] x 1.2 to 1.4

  • Dogs who are moderately active (1+ hrs walking) = [(weight in kg) ^0.75 x 70] x 1.4 to 1.8

  • Dogs who are highly active (working dogs, farm dogs) = [(weight in kg) ^0.75 x 70] x 1.8 to 3

  • Working dogs with multiple hours of strenuous activity (sled dogs) = [(weight in kg) ^0.75 x 70] x 3-6

Calculating Actual Caloric Intake

Estimating caloric intake is a great place to start, however it’s only one part of the picture when it comes to our dog’s caloric needs. The second part is to compare our estimates to the actual caloric needs and see where they fall. We also want to take a moment and look at the distribution of these calories to see how much comes from a complete and balanced food, and how much comes from unbalanced foods (treats, chews, additions or unbalanced supplements).

Calculating up your dog’s actual caloric intake is pretty simple. You just add up the calories of all items your dog is eating. For pre-packaged foods - look at the caloric density of the food ( kcals / cup ; kcals / ounce ; kcals / g ; kcals / kg ), then multiply this by the volume you are feeding. Don’t forget about any treats, chews, additions or supplments!

After we have the calories from each category, we then want to see what the percentage is of balanced diets vs. unbalanced foods. We want to aim for 90% of calories or more coming from complete and balanced diets, and less than 10% coming from unbalanced foods. The main reason for this is that most pet food manufacturers give you a slight “grace” in their formulations, allowing for you to provide your pet some treats, chews and other additions while still being able to meet your dog’s base nutritional needs for vitamins and minerals.

Example of Calculating Caloric Intake:

My 55 lb dog eats 1 cup twice daily of a kibble that is 450 kcals per day. My dog also eats 1 ounce of canned sardines (62 kcals), three biscuit treats (15 kcals each), and a 6” bully stick (100 kcals).

  • 450 kcals/cup x 2 cups per day = 900 kcals per day from kibble

  • 62 kcals (sardines) + 3 x 15 kcals (treats) + 100 kcals (bully stick) = 207 kcals from treats, chews and additions

Example of Calculating Caloric Distribution:

If we look at the example above, we can see that total calories consumed was 1107 kcals, balanced foods was 900 kcals, and unbalanced foods was 207 kcals. To calculate our caloric distribution we need to divide our balanced foods by the total and multiply by 100. Then take our unabalanced foods and divide by total calories and multiply by 100.

  • 900 / 1107 x 100 = 81%

  • 207 / 1107 x 100 = 19%

As you can see from the above example - we are feeding too many unbalanced foods. This means our example dog could have slight deficiencies within the diet. Typically in these situations the most common deficencies are limiting amino acids, b-vitamins, zinc, and selenium - these are used in the body to build proteins, help with organ function, and support the immune system. Having chronic deficiencies isn’t ideal.

Example of Comparing Actual Caloric Intake to Estimated Caloric Needs:

The next step is to compare our actual caloric intake to our estimated caloric needs. There are two things we really need to look at here - first is to see if our total amount of calories is appropriate for our dog, and the second is if our dog needs a diet designed for high or low calorie feeding.

For our 55 lb, Dog, the estimated caloric needs are between:

  • RER = 785 kcals ; RER x 1.6 = 1252

  • Actual Intake = 1207

If our example dog is at their ideal weight and body condition score - then that’s great! The actual intake isn’t significantly off the caloric needs for the “average” dog. This means any diet formulated to be complete and balanced for AAFCO nutrient profiles, when fed at 90% of the diet will provide adequate nutrition.

But if our example dog is overweight, or has a body condition score over 5 on a 9 point scale. This means we are likely overfeeding our dog, and our dog’s caloric needs actually fall below RER x 1.6 (which is what is currently being fed). Since our dog needs to be fed below RER x 1.6 to get to their ideal weight (and likely maintain it) we need a diet specifically formulated for low calorie, or restricted calorie feeding. If you simply reduced calories your dog could end up with significant long-term deficiencies.

A quick-check you can use if you are feeding a premade diet like a kibble is to look at the feeding recommendations - these are typically calculated for RER x 1.6. So if you are feeding below bag recommendations in order to help your dog’s maintain a healthy weight, then your dog likely has lower caloric needs.

The Nuance of Caloric Needs in Dogs

It’s really important to understand that the above are generalized calculations and recommendations. Any change to caloric intake - be that significantly eating more, or less food - should be a red flag. Some of the first signs of a disease process are changes to caloric intake. Being mindful of our dogs needs, and being able to recognize changes can be extremely useful. But sometimes it takes an experienced professional and an in-person examination to recognize a potential issue.

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