Carbohydrates in Dog and Cat Nutrition: What the Science Really Says

Pet owners are more label-savvy than ever, and one question keeps coming up: should dogs and cats eat carbohydrates? Some pet parents swear by grain-free, carb-free diets, while others rely on kibble that’s largely plant-based. But what does veterinary science say about whether our pets actually need carbohydrates?

Let’s take a closer look at what decades of research in canine and feline nutrition reveal.

Do Dogs and Cats Need Carbohydrates?

The short answer: No—at least, not in the way humans do.

Both dogs and cats have a metabolic requirement for glucose, but not necessarily for dietary carbohydrate. Their bodies can produce glucose from non-carbohydrate sources through a process called gluconeogenesis. This means that even without carbs in their diet, they can still maintain normal blood sugar levels, as long as they have enough high-quality protein and certain fats available.

Special Considerations for Life Stages

While adult dogs and cats can thrive without carbs, certain life stages demand extra glucose:

• Pregnancy – Growing puppies or kittens increase the dam’s energy needs, and glucose becomes a key fuel for fetal development.
• Lactation – Milk contains lactose, which is a carbohydrate, so producing milk requires more glucose.
• Growth – Very young animals have less digestive enzyme capacity for breaking down certain carbohydrates, and their bodies often prioritize glucose from protein sources.

Research shows that feeding pregnant dogs a carbohydrate-free diet can lead to complications such as low blood sugar, poor puppy survival rates, and smaller litter sizes—unless the protein content is increased to compensate.

Carbohydrate Digestion: How Dogs and Cats Differ

Both dogs and cats can digest cooked starch quite efficiently. However:

• Dogs have higher pancreatic amylase activity than cats, making them better at digesting starches.
• Cats are obligate carnivores with unique metabolic adaptations. They rely heavily on gluconeogenesis, even when dietary carbs are available.
• Both species digest starch better when it’s finely ground and cooked.

Raw starch, on the other hand, is poorly digested and can cause gastrointestinal upset.

Fiber: The Overlooked Carbohydrate

Fiber isn’t a required nutrient for dogs and cats, but it does have health benefits:

• Adds bulk to the diet for satiety
• Helps regulate bowel movements
• Supports gut health by feeding beneficial bacteria, which produce short-chain fatty acids

Sources of fiber in pet foods include beet pulp, tomato pomace, citrus pulp, pea fiber, and various grain hulls.

Lactose and Sugar Tolerance

Kittens and puppies can digest lactose (milk sugar) early in life, but many adult cats—and some adult dogs—lose the ability to process large amounts without digestive upset. Similarly, sucrose (table sugar) digestion is limited in young animals and should be avoided in orphaned or very young puppies and kittens.

The Bottom Line

• Dogs and cats don’t have a strict dietary requirement for carbohydrates, but they do require glucose—which they can produce from protein and fat.
• Life stages like pregnancy, lactation, and early growth increase glucose needs and may benefit from controlled carbohydrate inclusion.
• Cooking and processing dramatically improve starch digestibility.
• Fiber, while not essential, supports digestive health and satiety.
• Overloading pets with sugars or poorly digestible carbs can cause digestive issues.

Translation for pet parents: Focus less on whether carbs are “good” or “bad,” and more on the type, amount, and digestibility of carbohydrates in your pet’s diet. Always choose foods with high-quality protein as the foundation—and make sure the carbs that are present are there for a purpose, not just to fill the bag.

References

1. Case, L.P., Daristotle, L., Hayek, M.G., Raasch, M.F. (2023). Canine and Feline Nutrition: A Resource for Companion Animal Professionals, 3rd ed. Elsevier.
2. Romos DR, Belo PS, Bennink MR, et al. Effects of dietary carbohydrate, fat, and protein on growth, body composition, and blood metabolite levels in the dog. J Nutr. 1976;106:1452–1464.
3. Kienzle E. Carbohydrate metabolism in the cat. 2. Digestion of starch. J Anim Physiol Anim Nutr. 1993;69:102–110.
4. Rogers QR, Morris JG, Freedland RA. Lack of hepatic enzymatic adaptation to low and high levels of dietary protein in the adult cat. Enzyme. 1977;22:348–356.

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