Dogs Process Fat Better Than Carbs, New Study Finds

Your dog might be better suited to a carnivore’s diet than the kibble in their bowl suggests. A new study from Finland’s University of Helsinki reveals that canine metabolism responds more favorably to fat-rich foods than carbohydrate-heavy diets, challenging assumptions about what belongs in commercial dog food.

Researchers from the DogRisk research group tracked 46 Staffordshire Bull Terriers for about four and a half months, splitting them into two groups. One ate standard kibble packed with carbohydrates. The other consumed a raw meat-based diet rich in fat and essentially devoid of non-fiber carbs. The metabolic differences between the groups were striking.

Dogs munching kibble showed increases in long-term blood sugar, blood lipids, and body weight. Meanwhile, their raw-fed counterparts experienced drops in blood sugar, blood lipids, and glucagon levels. Both groups produced more ketone bodies (molecules generated when the body burns fat for fuel), but the raw food group’s levels were significantly higher, suggesting their bodies had shifted to preferentially burning fat for energy.

A Metabolic Profile That Raises Questions

Perhaps most intriguingly, the kibble-fed dogs developed metabolic markers that, in humans, would raise red flags. The raw food group showed a decrease in something called the triglyceride-glucose index, a measurement of insulin resistance that researchers have used in human studies but never before applied to dogs. The finding opens a window into understanding canine metabolism in new ways.

“Interestingly, the kibble diet was associated with changes often linked to adverse metabolic health, while the raw food diet promoted metabolic responses generally considered favorable,” said Dr. Sarah Holm, DVM and PhD, the study’s lead researcher from the DogRisk research group at the Faculty of Veterinary medicine, University of Helsinki.

She cautioned that more research is needed to understand what these metabolic shifts mean for dogs over the long haul. The study measured biomarkers over several months, but questions about lifetime health effects remain open.

Echoes of Human Nutrition Debates

The parallels to contentious debates in human nutrition are hard to ignore. For decades, dietary fat was vilified as a driver of heart disease and metabolic dysfunction. More recent research has complicated that picture, with some studies suggesting that fat-rich, low-carbohydrate diets can actually improve certain metabolic markers.

“This is a great example of One Health research. Our findings reflect similar, and sometimes controversial, human studies suggesting that fat-rich diets actually lower cholesterol and triglycerides, while carbohydrate-rich diets raise blood lipids and long-term blood sugar, a known precursor to type 2 diabetes in humans,” Dr. Anna Hielm-Bjorkman, DVM and docent, who leads the DogRisk group, added.

The One Health framework recognizes that human, animal, and environmental health are deeply interconnected. In this case, dogs may serve as useful models for understanding human metabolic responses to different macronutrient profiles. The digestive systems differ, of course (humans have longer digestive tracts and produce amylase in saliva, while dogs produce it primarily in the pancreas), but the metabolic machinery shares enough common ground to make cross-species comparisons meaningful.

The study does not resolve the larger question of what diet is optimal for dogs, and it was not designed to. Raw diets carry their own risks, including bacterial contamination and nutritional imbalances if not carefully formulated. Commercial kibble, meanwhile, offers convenience and quality control but may not align perfectly with canine evolutionary history as opportunistic carnivores.

What the research does suggest is that the macronutrient composition of dog food matters more than previously appreciated. If carbohydrate-heavy diets are pushing dogs toward metabolic states associated with poor health outcomes, pet food manufacturers and veterinarians may need to rethink standard recommendations. The findings were published in The Veterinary Journal in October.

The Veterinary Journal: 10.1016/J.TVJL.2025.106462