How high-fat diets provide sustained energy for dogs

As we head out for outdoor summer adventures with our pups, we’re particularly mindful of feeding the best dog food for active dogs. Leading canine nutrition expert and professional sled dog racer, Dr. Mark Roberts, Ph.D., explains how high-fat, low-carb diets provide sustained energy for dogs. Read on or WATCH here.

When looking at the best source of sustained energy for dogs, let’s examine the impact energy of each macronutrient: carbohydrates, protein and fat. Understanding the basic concept of how each energy source is used and stored by a dog allows us to determine which is optimal for keeping their energy levels high throughout the duration of a day (spoiler alert: raw, low-carb, high-fat food is the winner!).

Key Takeaways:

• Using carbohydrates as the primary energy source for a dog will drive glucose spikes, flooding its body with insulin from the pancreas, and giving it a burst of energy followed by feeling depleted.

• When protein is used as a primary energy source, it isn’t available to perform other important functions in a dog’s body.

• Fat provides the most sustained energy source, and reduces the glucose and insulin spikes high-carb diets cause.

Carbohydrates

Extruded (kibble) diets contain a significant amount of carbohydrates that a dog uses for energy. Within a dog’s body, carbohydrates are broken down to form glucose, with oxidation (fuel-burning) providing the most rapid supply of energy. Unfortunately, glucose also has the smallest amount of storage in a dog’s body, primarily in skeletal muscle and the liver (1) (in the form of glycogen). When a dog consumes a high-carbohydrate diet, as glucose levels rise, referred to as a “glucose spike,” insulin is released from the pancreas to bring glucose levels down (2). The impact on a dog? Giving it a burst of energy, followed by feeling tired and depleted. Moreover, if a dog has an active lifestyle, the potential exists that the limited storage of carbohydrates (or glycogen) in the animal’s body might run out (3). At this point, the dog will become fatigued, unless more carbohydrates are consumed.  

Protein

Surprisingly, protein can also be utilized as a source of energy by a dog. They achieve this by the  biosynthesis of glucose from certain non-carbohydrate sources using metabolic pathways (4). Specific amino acids (which make up protein) are used for this process to occur, with serine and alanine (5) major contributors. However, despite this, mobilizing protein to be used as the primary energy source is not advantageous, due to the macronutrient being needed for many other important functions, such as enabling chemical messengers and important reactions to occur. Additionally, breaking down protein from muscles is clearly not an optimal approach for the health of a dog.

Fat

One advantage of fat is that it’s significantly more energy dense than both protein and carbohydrates, with a gram of fat producing 8.5 kcals, compared to 3.5 kcals both from protein and carbohydrate. (This is why Bones & Co. raw recipes, with a 1:1 fat-to-protein ratio and less than 1% carbohydrates, are upwards of 40% more calorie-dense than other commercially prepared raw diets.) Other than being sourced from its diet, bodyfat from the animal can also be used for energy, with even a very lean dog possessing sufficient fat stores containing thousands of kcals of accessible energy.

When fat is the primarily energy source for a dog, an increase in fatty acids and glycerol occurs (from the breaking down of triglycerides). When this happens, two key processes take place. The first involves a significant reduction in the use of stored carbohydrate (glycogen) in dogs (6). This is beneficial, in that by keeping these stores stable, reduces the potential of “running out,” of a quick source of energy if needed. The second process resulting from the breaking down of fat by a dog, is a substantial switch to using non-carbohydrate sources for energy (fat) from carbohydrates (7).

Additionally, when a dog is using fat instead of glucose for energy, it also produces ketones, or ketone bodies, which can provide an alternative fuel source to glucose for cells in various organs and tissues, including the brain (8). These factors are reflected in the Bones and Co range, with dietary fat being the dominant macronutrient.

From the perspective of glucose and insulin dynamics, the difference between carbohydrates being the main fuel source to fat is considerable. The elevation in glucose and insulin concentrations, witnessed in high carbohydrate fed dogs does not occur in those animals after consuming a high-fat, low-carbohydrate diet, even if the dog has been fasting. This in turn, eliminates the highs and lows of energy commonly witnessed in dogs fed high-carbohydrate diets.

The bottom line regarding sustained energy for a dog

There can be no doubt that a high fat, moderate protein diet, with no, or a very minimal inclusion of carbohydrate content is the optimal approach to provide a dog with sustained energy. Not only does dietary fat provide over twice as much energy to a dog, compared to protein and carbohydrates, but it does so, on a constant, steady basis. Moreover, it reduces the rate of depletion from stored carbohydrate in the animal; ironically, much more so, than if carbohydrates are the main source of energy, whereby constant carbohydrate resupply is needed in dogs with an active lifestyle (3).

References

1.      Brännback, E. (2020). The effect of two diets with different carbohydrate content on glucose markers in dogs. Animal Nutrition.

2.      Nguyen, P., Dumon, H., Buttin, P., Martin, L., & Gouro, A. S. (1994). Composition of meal influences changes in postprandial incremental glucose and insulin in healthy dogs. The Journal of nutrition, 124, 2707S-2711S.

3.      Reynolds, A. J., Fuhrer, Laurent., Dunlap, H. L., Finke, Mark., & Kallfelz, F. A. (1995). Effect of diet and training on muscle glycogen storage and utilization in sled dogs. Journal of applied physiology, 79(5), 1601-1607.

4.      Belo, P. S., Romsos, D. R., & Leveille, G. A. (1977). Influence of diet on lactate, alanine and serine turnover and incorporation into glucose in the dog. The Journal of Nutrition, 107(3), 397-403.

5.      Kuttner, R. E., & Spitzer, J. J. (1978). Gluconeogenesis from alanine in endotoxin-treated dogs. Journal of Surgical Research, 25(2), 166-173.

6.      Shulman, G. I., Lacy, W. W., Liljenquist, J. E., Keller, U., Williams, P. E., & Cherrington, A. D. (1980). Effect of glucose, independent of changes in insulin and glucagon secretion, on alanine metabolism in the conscious dog. The Journal of Clinical Investigation, 65(2), 496-505.

7.      Chu, C. A., Sherck, S. M., Igawa, K., Sindelar, D. K., Neal, D. W., Emshwiller, M., & Cherrington, A. D. (2002). Effects of free fatty acids on hepatic glycogenolysis and gluconeogenesis in conscious dogs. American Journal of Physiology-Endocrinology and Metabolism, 282(2), E402-E411.

8.      Vendramini, T. H., Amaral, A. R., Rentas, M. F., Nogueira, J. P. D. S., Pedrinelli, V., de Oliveira, V. V., ... & Brunetto, M. A. (2024). Ketogenic diets: A systematic review of current scientific evidence and possible applicability in dogs and cats. Journal of Animal Physiology and Animal Nutrition, 108(2), 541-556.