What science says about carbs in your dog's diet
Apr 18, 2026
What science says about carbs in your dog's diet
Most commercial dog foods are 30–60% carbohydrates by caloric content. Yet dogs have no established nutritional requirement for carbohydrates whatsoever. That disconnect is worth understanding — because the science of how dogs process carbs is quite different from how humans do.
How dogs digest carbohydrates
The key difference starts with amylase — the enzyme responsible for breaking down starchy carbohydrates. Humans produce amylase in large quantities in their saliva, beginning the digestion of carbs the moment food enters the mouth.
Dogs produce very little salivary amylase. While they do produce some pancreatic amylase, the overall capacity to efficiently break down complex carbohydrates is significantly lower than in humans or true omnivores. This is consistent with their evolutionary history as primarily carnivorous animals whose natural diet consisted almost entirely of animal protein and fat.
What happens when dogs eat too many carbs
When a dog consumes a high-carbohydrate meal, blood glucose rises rapidly. The pancreas responds by releasing insulin to manage that spike. In a dog eating a consistently high-carb diet, this cycle repeats multiple times daily — and over time it can lead to insulin resistance, where the body becomes progressively less effective at regulating blood sugar.
The downstream effects of chronic high-carb intake in dogs include:
Excess carbohydrates that aren't immediately used for energy get stored as fat, contributing to weight gain and obesity. Obese dogs face significantly elevated risks of joint problems, inflammation, cardiovascular issues and reduced lifespan.
Persistent insulin dysregulation increases the risk of canine diabetes mellitus — a condition that has been rising in prevalence alongside the dominance of high-carb commercial pet food.
Chronic inflammation, linked to both excess body fat and the blood sugar volatility caused by high-carb feeding, is associated with a range of long-term health problems in dogs.
What dogs are built to run on
Dogs metabolise fat extremely efficiently. In the absence of dietary carbohydrates, a dog's liver converts fat into ketone bodies — an alternative fuel source that the brain, heart and muscles can use directly. This is the same metabolic state that forms the basis of the ketogenic diet in both humans and dogs.
Research from KetoPet Sanctuary — which investigated ketogenic nutrition in dogs with cancer — found that dogs on a very low-carb, high-fat diet maintained healthy blood glucose and produced measurable ketone levels, supporting the idea that fat-based metabolism is not just tolerated but well-suited to canine biology.
KetoPet Sanctuary's findings were formally documented in a three-part series published in IVC Journal — Innovative Veterinary Care, a peer-reviewed publication for veterinary professionals. The study open-enrolled 40 dogs with advanced cancer on a ketogenic diet combined with hyperbaric oxygen therapy. KetoPet observed that a ketogenic diet could improve survivorship beyond the initial prognosis for some forms of cancer when used as adjunctive therapy, with 55% of dogs who graduated the program going on to experience a quality of life far beyond their original prognosis. IVC Journal
KetoPet Sanctuary demonstrated the utility of a canine diet that induces nutritional ketosis — showing that when strictly adhered to, a ketogenic diet increases the efficacy of standard of care treatments, prolonging both survival and quality of life in canine cancer patients. IVC Journal
The full research is available at IVC Journal: Part 1 | Part 2 | Part 3
The practical implication
None of this means carbohydrates are acutely toxic to dogs — most dogs can tolerate them to a degree. But tolerance is not the same as optimal. A diet that more closely reflects what a dog's digestive system evolved to process — high in animal protein and fat, low in carbohydrates — is more aligned with the science of canine nutrition than the carb-heavy formulations that dominate the market.
When evaluating any dog food, the most important number to look for is net carbohydrate content. Most brands don't list it clearly, which makes independent assessment difficult. Look for foods with verifiable carb content and animal protein as the primary ingredient.
This post is for informational purposes only and does not constitute medical advice. Always consult a qualified veterinarian regarding your dog's specific dietary needs.
