Assessing Carbohydrate Content in Commercial Dry Dog Food
In canine nutrition, the proportion and quality of macronutrients directly affect metabolic health, digestive efficiency, and long-term well-being. While protein and fat content are emphasized in most commercial dry dog food formulations, carbohydrates—often not explicitly labeled—constitute a substantial portion of these products. Understanding how to calculate carbohydrate content from available data, and interpreting what it implies about ingredient composition, is essential for professionals and informed pet guardians alike.
Carbohydrates in Dry Food
Unlike human nutrition labeling standards, pet food manufacturers are not required to declare carbohydrate contenton the guaranteed analysis. However, carbohydrates can be estimated by difference, based on the assumption that the total composition of the food must equal 100%. This estimate includes not only starches and sugars but also soluble and insoluble fibers.
A high carbohydrate percentage is often indicative of a lower overall inclusion of animal-derived ingredients, particularly when economic formulation strategies prioritize cost-effective plant-based fillers over species-appropriate protein sources.
How to Calculate Carbohydrate Content in Dry Dog Food
To estimate the carbohydrate content, commonly expressed as Nitrogen-Free Extract (NFE), the following formula is used:
Carbohydrates (NFE, %) = 100 – Crude Protein – Crude Fat – Crude Fiber – Moisture – Ash
If ash content is not disclosed (which is common), it may be estimated at 6–8% for typical extruded kibble.
EXAMPLE
A dry food with the following guaranteed analysis:
Crude Protein: 26%
Crude Fat: 14%
Crude Fiber: 4%
Moisture: 10%
Ash: Estimated at 7%
Carbohydrate estimate:
NFE = 100 – 26 – 14 – 4 – 10 – 7 = 39%
This formulation contains approximately 39% carbohydrates as fed.
Adjusting to Dry Matter Basis
To accurately compare products with differing moisture levels (e.g., between kibble and raw or canned food), values must be converted to a dry matter basis (DMB) using the formula:
Dry Matter (%) = Nutrient % / (100 – Moisture %) × 100
In the above example:
DMB Carbohydrates = 39 / (100 – 10) × 100 = 43.3%
This indicates that 43.3% of the food’s dry matter is composed of carbohydrates, a value that would be considered excessive in a species-appropriate formulation.
High Carbohydrate Content
A high NFE is typically a proxy indicator of low inclusion rates of animal-sourced ingredients. This is particularly relevant in extruded (kibble) products, where starches are required to facilitate the extrusion process. Starches provide the structural matrix that allows kibble to maintain its shape, expand, and remain shelf-stable.
Even when a product lists “fresh meat” as the first ingredient, it is important to consider that fresh meat is approximately 70–75% water by weight. During the high-heat extrusion process, this water is removed, reducing the relative contribution of fresh meat in the final product. As a result, the actual proportion of high-quality animal protein is significantly lower than suggested by ingredient order alone.
Furthermore, total crude protein values can be misleading, as they may include proteins from less bioavailable or incomplete sources, such as:
Meat meals of unspecified quality
Wheat gluten
Soy protein concentrates
Pea or lentil proteins
While these ingredients increase the measured protein percentage, they are not equivalent to animal-based proteins in terms of amino acid profile, digestibility, or functional support for carnivorous physiology.
Health Considerations of Excessive Carbohydrate Intake in Dogs
Dogs are classified as facultative carnivores, capable of digesting carbohydrates to a limited extent, but not adapted to high-carbohydrate diets long-term. Diets containing >30–35% carbohydrates (on a dry matter basis) have been associated with:
Elevated postprandial glucose and insulin levels
Weight gain and obesity
Chronic low-grade inflammation
Disruption of gut microbiota balance
Increased risk of metabolic and endocrine disorders
While some carbohydrate inclusion can be beneficial—particularly from fiber-rich, whole food sources—the high levels present in most dry foods are primarily a consequence of manufacturing constraints and economic considerations, not nutritional necessity.
Conclusion
Calculating the carbohydrate content of dry dog food provides critical insight into both the nutrient profile and the quality of the ingredient composition. High carbohydrate levels are typically associated with reduced animal protein inclusion and the use of cost-effective plant-based fillers, which may not align with the biological needs of dogs.
Professionals and pet guardians seeking to optimize canine health should evaluate carbohydrate levels alongside sourcing transparency, protein quality, and processing methods. When possible, opt for diets with higher proportions of bioavailable animal proteins, lower processed starches, and minimal reliance on extrusion.