Why High-Carbohydrate Commercial Dog Food Can Harm Your Dog’s Health

Dog Biology and Digestive Physiology

Dogs are considered facultative carnivores. This means they are capable of digesting some plant-based foods, but their digestive system is primarily adapted to process animal proteins and fats.

While dogs can digest some starch, their metabolism still functions best when the majority of calories come from animal-based nutrients.

Natural Diet vs Commercial Dog Food

In a natural prey-based diet, such as what wild canids consume, the approximate energy distribution looks like this:

• Protein: around 50–55% of calories
• Fat: around 40–45% of calories
• Carbohydrates: typically less than 10%

This composition supports muscle development, stable energy levels, and healthy metabolic function.

In contrast, many commercial dog foods contain:

• Protein: 20–30%
• Fat: 10–25%
• Carbohydrates: often 35–50%

High levels of carbohydrates are often included because they are cheaper and easier to process during manufacturing. To understand how to feed a balanced diet instead, see our Raw Diet vs Kibble guide.

Potential Effects of High-Carbohydrate Diets

When dogs consume diets that are significantly higher in carbohydrates than their natural intake, several issues may develop over time.

Digestive changes

Excess carbohydrates can alter the gut microbiome, encouraging bacteria that ferment carbohydrates instead of those that specialize in protein digestion.

Energy fluctuations

High carbohydrate intake may cause spikes and drops in blood sugar, leading to unstable energy levels.

Skin and allergy issues

Some studies suggest that certain carbohydrate sources, especially grains, may contribute to dermatological issues in susceptible dogs.

Weight gain

Excess carbohydrates can increase calorie intake and contribute to obesity when not balanced with sufficient activity.

Scientific Research

Several veterinary studies have investigated the relationship between diet composition and canine health.

• Hewson-Hughes et al., 2011: Geometric analysis of macronutrient selection in dogs (Journal of Experimental Biology)
• Bosch et al., 2015: The nutrition of carnivorous animals: dogs and wolves (Animal Frontiers)
• BMC Veterinary Research, 2021: Limited-ingredient diets improving symptoms in dogs with food sensitivities.

These studies suggest that dogs naturally regulate their intake toward higher protein and fat ratios when given the option.

Practical Recommendations

To support your dog’s health:

• Choose foods with higher protein content from quality animal sources
• Avoid excessive fillers such as corn, wheat, and soy
• Include fresh whole foods when possible, such as meat, eggs, or organs
• Monitor your dog’s skin condition, stool quality, and energy levels

Every dog is different, so dietary changes should be introduced gradually and adjusted based on the dog’s health and activity level. For more specifics, check out our FAQ section.