Cats are obligate carnivores that naturally rely on protein and fat as their primary energy sources, and carbohydrates are not nutritionally essential in their dietary requirements. This is because cats possess a strong capacity for gluconeogenesis\u2014producing the glucose they need in the liver from amino acids and fats\u2014allowing them to survive without consuming dietary carbohydrates.<\/p>\n\n\n\n
However, in the manufacturing of modern dry cat food (kibble), carbohydrates play an extremely important role. The main reason is that starch contained in carbohydrates is indispensable as a \u201cstructural forming agent\u201d during the high-temperature, high-pressure extrusion process, where it binds other ingredients together and creates the characteristic shape and texture of kibble.<\/p>\n\n\n\n
In addition, when carbohydrates are properly heat-processed (gelatinized), they can become a highly digestible and efficient energy source even for cats. In this article, we scientifically explain cats\u2019 physiological characteristics and the limitations of carbohydrate metabolism, clarify the technical role of carbohydrates in dry food production, compare major carbohydrate ingredients, and provide practical formulation design guidelines.<\/p>\n\n\n\n
To discuss carbohydrate utilization in cat food, it is essential to understand cats\u2019 unique physiology and metabolic systems. This understanding is a fundamental prerequisite for designing safe and effective formulations.<\/p>\n\n\n\n
Through their evolution as carnivores, cats have developed a physiology with limited capacity to utilize carbohydrates. Therefore, formulation designs that ignore these physiological traits can carry health risks for cats.<\/p>\n\n\n\n
Below are the key physiological constraints related to carbohydrate utilization in cats.<\/p>\n\n\n\n
Compared with omnivorous dogs, cats have a shorter digestive tract, specialized to efficiently digest and absorb diets high in protein and fat. This anatomy suggests that cats are less suited to slowly breaking down and fermenting complex carbohydrates over time.<\/p>\n\n\n\n
Cats do produce pancreatic amylase (though generally less than dogs and omnivores), but unlike dogs, they do not have salivary amylase. As a result, cats are often considered less capable of digesting large amounts of carbohydrates at once.<\/p>\n\n\n\n
In the feline liver, the activity of glucokinase\u2014an enzyme important for taking up glucose in response to rising blood glucose\u2014is low. This creates broader limitations in the ability to metabolize dietary carbohydrates.<\/p>\n\n\n\n
As noted above, cats constantly maintain active gluconeogenesis, synthesizing glucose in the liver from amino acids (protein) and glycerol (fat), even when they do not consume dietary carbohydrates. This is strong physiological evidence that carbohydrates are not an essential energy source for cats.<\/p>\n\n\n\n
Because of these physiological constraints, if cats consume carbohydrates beyond their processing capacity, the risk increases for gastrointestinal issues such as diarrhea and bloating due to poor digestion, as well as potential blood glucose abnormalities when carbohydrate load exceeds metabolic limits.<\/p>\n\n\n\n
These constraints mean that the \u201ctolerable range\u201d of carbohydrates in cat food formulation can be relatively narrow, and the precision of ingredient selection and processing technology becomes a direct determinant of product success.<\/p>\n\n\n\n
That said, as explained in the next section, appropriate manufacturing technology can help overcome these limitations and allow carbohydrates to be used safely and beneficially in cat food.<\/p>\n\n\n\n
If carbohydrates are not nutritionally essential for cats, why are they major components in many dry foods? The answer lies in the fact that carbohydrates are essential not only as an energy source but also as a physical \u201cstructural forming agent\u201d required to create kibble\u2019s unique shape and texture.<\/p>\n\n\n\n
The role of carbohydrates (starch) in the extrusion process can be understood through the following technical aspects.<\/p>\n\n\n\n
In dry food manufacturing, ingredients are mixed and passed through an extruder under high temperature and pressure. During this process, starch undergoes structural changes due to heat and moisture: its crystalline structure breaks down and it becomes gel-like.<\/p>\n\n\n\n
This is called gelatinization. Gelatinized starch becomes highly viscous and functions as a \u201cbinder,\u201d gluing together other ingredient particles such as meat meals and fats.<\/p>\n\n\n\n
In addition, starch gelatinizes inside the extruder under high temperature and pressure, and when the material exits the die, pressure drops suddenly and the product expands. Gelatinized starch stabilizes the porous, sponge-like structure at this moment, creating the crunchy texture characteristic of kibble.<\/p>\n\n\n\n
The extent to which starch has gelatinized is expressed as the \u201cdegree of gelatinization,\u201d and it is an extremely important parameter that determines finished product quality.<\/p>\n\n\n\n
Benefits of a high degree of gelatinization<\/span><\/strong> \u203btarget guideline: 90% or higher<\/p>\n\n\n\n Drawbacks of a low degree of gelatinization<\/span><\/strong><\/p>\n\n\n\n The degree of gelatinization is strongly influenced by extrusion conditions, particularly the thermal energy applied to the ingredients (Specific Thermal Energy: STE).<\/p>\n\n\n\n Studies show that higher STE improves gelatinization and kibble expansion, and as a result, can increase palatability. Conversely, low-STE conditions can lead to insufficient gelatinization, increased fermentation in feces, and potentially greater digestive burden.<\/p>\n\n\n\n In conclusion, carbohydrates that have been properly gelatinized through manufacturing technology can overcome cats\u2019 physiological constraints and become a highly digestible energy source (with digestibility exceeding 93%). Under appropriate extrusion conditions, digestibility may reach 98% or higher for starch sources such as white rice or cassava, as some reports indicate.<\/p>\n\n\n\n Therefore, the value of carbohydrates is determined not only by the intrinsic properties of the ingredient, but also by how effectively it is processed using advanced manufacturing technology. Next, we compare the characteristics of specific carbohydrate ingredients.<\/p>\n\n\n\n When designing a dry food formula, selecting the optimal carbohydrate sources requires a multi-angle evaluation of nutritional and physicochemical properties across a wide range of ingredients. Here we compare six major carbohydrate ingredients.<\/p>\n\n\n\n To make this comparison more actionable, below is a detailed discussion of each ingredient.<\/p>\n\n\n\n White rice is a representative high-GI ingredient (approximately 70\u201390). It contains extremely little dietary fiber, and because of starch characteristics (largely amylopectin), it gelatinizes easily with heat processing and shows high digestibility.<\/p>\n\n\n\n Because it gelatinizes well and is highly digestible, it is easy to use as a stable energy source. However, due to its high GI, it may raise blood glucose rapidly, so high inclusion requires careful consideration of glycemic load.<\/p>\n\n\n\n Corn has a mild sweetness and a medium GI (about 52\u201360). Its gelatinization behavior is good, and during extrusion it contributes to kibble expansion.<\/p>\n\n\n\n It is widely used because of stable quality and strong processing suitability. Some studies report higher glycemic response compared with other carbohydrate sources, while other studies describe a relatively moderate response\u2014suggesting that form and degree of processing can affect outcomes.<\/p>\n\n\n\n Wheat has a relatively lower GI (about 41\u201355). It contains gluten, which improves stickiness and expansion, providing manufacturing advantages. It also contains vitamins and minerals.<\/p>\n\n\n\n Wheat offers excellent binding properties and helps improve kibble physical quality. Absorption tends to be slower than rice or corn.<\/p>\n\n\n\n Potato is a high-GI ingredient similar to rice (generally 75 or higher). It is composed almost entirely of starch, with high amylopectin content, resulting in very strong gelatinization and substantial improvements in kibble density and expansion.<\/p>\n\n\n\n It is often used as a main energy source in grain-free products and has excellent processing performance. However, because it is high GI, attention is needed regarding rapid glycemic response. The glycemic load of potato-containing foods is considered to vary depending on the balance with protein and fat.<\/p>\n\n\n\n Tapioca is a starch derived from cassava root and contains almost no dietary fiber. It has extremely high gelatinization capacity and is widely used, alongside potato, in grain-free products as an alternative carbohydrate source.<\/p>\n\n\n\n Studies confirm digestibility comparable to white rice. GI data vary, but some trials report more moderate glycemic responses compared with corn or white rice.<\/p>\n\n\n\n Legumes have a very low GI (peas around 48, lentils around 29). They are rich in dietary fiber and plant protein. Because part of their starch acts as \u201cresistant starch\u201d (less digestible), digestion and absorption are slower.<\/p>\n\n\n\n Because they are low GI and high in fiber, they may help support blood glucose control and improve stool quality. Studies report that lentil-based diets showed little to no postprandial blood glucose rise.<\/p>\n\n\n\n However, legumes may contain anti-nutritional factors (a general term for compounds that can interfere with nutrient metabolism or absorption), so formulas that replace carbohydrates predominantly with legumes should be evaluated carefully for potential reductions in digestibility.<\/p>\n\n\n\n As this analysis shows, each carbohydrate ingredient has both strengths and limitations, and no single ingredient is \u201cuniversally superior.\u201d Developers must understand these properties deeply and combine them strategically according to the product concept and the target cat\u2019s health status. In the next section, we provide formulation design guidelines based on these insights.<\/p>\n\n\n\n Below are practical formulation design guidelines that integrate the analysis above and can be applied directly to product development. Developers must continuously link three perspectives\u2014feline physiology, ingredient properties, and manufacturing technology\u2014when building an optimal formula.<\/p>\n\n\n\n Carbohydrate content must be determined within the overall nutritional balance of the product.<\/p>\n\n\n\n To ensure carbohydrate digestibility and safety, controlling gelatinization in manufacturing is a top priority.<\/p>\n\n\n\n Relying on a single carbohydrate source increases risk. Instead, strategically combine multiple ingredients with different characteristics to optimize the nutritional profile.<\/p>\n\n\n\n Manufacturing conditions are inseparable from formulation design.<\/p>\n\n\n\n These guidelines form the foundation for developing high-quality cat food that is safe, highly digestible, and supportive of feline health. Building on this foundation by incorporating consumer needs and the latest research trends leads to more competitive product development.<\/p>\n\n\n\n\n
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Relationship with processing conditions<\/h4>\n\n\n\n
\n\n\n\nComparative analysis of major carbohydrate ingredients<\/h2>\n\n\n\n
Ingredient<\/th> GI Category<\/th> Gelatinization<\/th> Dietary Fiber<\/th> Key Benefits<\/th> Points to Watch<\/th><\/tr><\/thead> White rice<\/strong><\/td> High GI (approx. 70\u201390; varies by variety and polishing)<\/td> High<\/td> Very low<\/td> Highly digestible; rapid energy supply<\/td> Tends to increase blood glucose quickly; monitor glycemic load and stool quality at high inclusion levels<\/td><\/tr> Corn<\/strong><\/td> Medium GI (approx. 52\u201360)<\/td> Good (requires slightly higher temperature range)<\/td> Moderate (higher if whole grain)<\/td> Good processing performance; contributes to expansion<\/td> Glycemic response may vary depending on ingredient form and processing<\/td><\/tr> Wheat<\/strong><\/td> Low to medium GI (approx. 41\u201355)<\/td> Good<\/td> Moderate<\/td> Gluten-derived binding improves kibble formation; contains micronutrients<\/td> Some markets prefer wheat-free formulas (true allergy is rare)<\/td><\/tr> Potato<\/strong><\/td> High GI (when warm, often exceeds 75\u2013100)<\/td> Very high<\/td> Low<\/td> Excellent gelatinization; enhances kibble physical structure<\/td> Rapid blood glucose response; high inclusion may soften stools<\/td><\/tr> Tapioca (cassava)<\/strong><\/td> Medium to high GI (approx. 56\u201390)<\/td> Very high<\/td> Very low<\/td> Highly digestible; neutral flavor; suitable for grain-free design<\/td> Nutritionally almost pure starch; high inclusion may cause loose stools<\/td><\/tr> Legumes (peas, lentils)<\/strong><\/td> Low GI (e.g., peas ~48; lentils ~29)<\/td> Moderate<\/td> High (consider soluble\/insoluble balance)<\/td> Low GI; rich in dietary fiber; plant protein source<\/td> Resistant starch may reduce digestibility at high inclusion levels<\/td><\/tr><\/tbody><\/table><\/figure>\n\n\n\n 1. White rice (milled rice)<\/h3>\n\n\n\n
Characteristics<\/span><\/h4>\n\n\n\n
Formulation benefits and cautions<\/span><\/h4>\n\n\n\n
2. Corn<\/h3>\n\n\n\n
Characteristics<\/span><\/h4>\n\n\n\n
Formulation benefits and cautions<\/span><\/h4>\n\n\n\n
3. Wheat<\/h3>\n\n\n\n
Characteristics<\/span><\/h4>\n\n\n\n
Formulation benefits and cautions<\/span><\/h4>\n\n\n\n
4. Potato<\/h3>\n\n\n\n
Characteristics<\/span><\/h4>\n\n\n\n
Formulation benefits and cautions<\/span><\/h4>\n\n\n\n
5. Tapioca (cassava)<\/h3>\n\n\n\n
Characteristics<\/span><\/h4>\n\n\n\n
Formulation benefits and cautions<\/span><\/h4>\n\n\n\n
6. Legumes (peas, lentils)<\/h3>\n\n\n\n
Characteristics<\/span><\/h4>\n\n\n\n
Formulation benefits and cautions<\/span><\/h4>\n\n\n\n
\n\n\n\nTechnical guidelines for formulation design<\/h2>\n\n\n\n
Setting total carbohydrate level<\/h4>\n\n\n\n
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In general adult maintenance complete-and-balanced dry foods, total carbohydrate content is commonly designed around 30\u201335%.<\/li>\n\n\n\n
For therapeutic diets aimed at managing diabetes or obesity, or for senior cat formulas, carbohydrate levels may be reduced to 20% or lower.
Determining carbohydrate level is not simply a matter of setting inclusion rates; it is also a strategic decision to manage nutritional and cost trade-offs among protein, fat, and carbohydrates.<\/li>\n<\/ol>\n<\/div><\/div><\/div><\/div>\n\n\n\nManaging degree of gelatinization and target values<\/h4>\n\n\n\n
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Aim for a degree of gelatinization of 90% or higher during extrusion.<\/li>\n\n\n\n
High gelatinization is directly linked to improved digestibility, better palatability, and favorable stool quality. Conversely, low gelatinization increases the risk of indigestion and abnormal fermentation in the gut. This requires optimizing manufacturing conditions (temperature, pressure, moisture, residence time, etc.) and building the technical capability to consistently achieve high gelatinization.<\/li>\n<\/ol>\n<\/div><\/div><\/div><\/div>\n\n\n\nBalancing ingredient combinations<\/h4>\n\n\n\n
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For example, when using high-GI potato, combining it with low-GI, fiber-rich legumes can help mitigate rapid postprandial blood glucose rises.<\/li>\n\n\n\n
In addition to the starch source that forms kibble structure, it is common to add small amounts of functional fiber sources such as cellulose (insoluble fiber) or beet pulp to adjust stool firmness and volume.<\/li>\n<\/ol>\n<\/div><\/div><\/div><\/div>\n\n\n\nIntegration with the manufacturing process<\/h4>\n\n\n\n
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Higher thermal energy (high STE) can improve kibble expansion and gelatinization and may increase palatability.<\/li>\n\n\n\n
Excessive heat can also destroy heat-sensitive nutrients such as certain vitamins. Formulators must work closely with manufacturing teams to identify optimal processing conditions that maximize ingredient performance while minimizing nutrient losses.<\/li>\n<\/ol>\n<\/div><\/div><\/div><\/div>\n\n\n\n