Diabetic Cats, Diet, Carbs, Fats, Protein, The Glycemic Index, Crude Analysis and Dry Cat Food
If cats cannot digest carbs why would the glycemic index apply to a cat?
Great question! Cats are obligate carnivores, meaning their bodies are adapted to digest and utilize protein and fat rather than carbohydrates. However, while they have a limited ability to process carbohydrates, they can absorb simple sugars and use them for energy to some extent.
The glycemic index (GI) is a measure of how quickly a food raises blood sugar levels. Even though cats do not require carbohydrates in their diet, many commercial cat foods—especially dry kibble—contain carbs like rice, potatoes, or corn. These ingredients can still impact a cat’s blood sugar levels, which is why the GI can be relevant.
In diabetic cats, for example, high-GI foods (which rapidly increase blood sugar) can cause spikes that worsen insulin resistance. In contrast, low-GI foods lead to slower, steadier glucose absorption, which is better for managing diabetes or preventing obesity.
That said, GI isn't as widely used in feline nutrition as it is in humans because cats primarily rely on protein and fat for energy. The more critical factor in cat diets is ensuring low-carb, high-protein nutrition to align with their natural metabolic needs.
What are the simple sugars in cats blood and humans blood?
In both cats and humans, the primary simple sugar circulating in the blood is glucose. However, there are some key differences in how their bodies handle it:
Glucose – The main sugar used for energy in both cats and humans. It comes from dietary carbohydrates (in humans) or from protein metabolism (in cats, via gluconeogenesis).
Fructose – Present in very small amounts, primarily from dietary sources (more common in humans, as cats lack a natural dietary source of fructose).
Galactose – Found in minimal amounts, mainly from the breakdown of lactose (milk sugar), but adult cats generally have low lactose tolerance.
Key Differences Between Cats and Humans:
Humans efficiently metabolize dietary carbohydrates into glucose and regulate blood sugar using insulin.
Cats primarily generate glucose from protein (gluconeogenesis) since their natural diet (meat) contains little to no carbohydrates.
Cats have lower insulin sensitivity than humans and rely less on glucose for energy, favoring fat and protein metabolism.
Normal blood glucose levels in cats range from 60–120 mg/dL, whereas in humans, it's around 70–100 mg/dL fasting.
Even though both species rely on glucose for essential functions, the source and metabolism of that glucose are quite different!
How specifically does the glycemic index apply to cats?
The glycemic index (GI) applies to cats primarily in relation to blood sugar regulation, especially for cats with diabetes or weight management issues. However, since cats are obligate carnivores with a metabolism focused on protein and fat, the concept of GI is less relevant to them compared to omnivores like humans or dogs.
Although cats have a limited ability to process carbohydrates, they can still absorb simple sugars. High-GI foods (e.g., rice, potatoes, corn) can lead to rapid blood sugar spikes, which can contribute to insulin resistance and diabetes.
Low-GI foods (e.g., lentils, peas, chickpeas) cause a slower, more gradual rise in blood sugar, which is better for diabetic or overweight cats.
Relevance to Feline Diabetes
Diabetic cats struggle with insulin regulation, so minimizing blood sugar spikes is crucial.
A low-GI, high-protein diet (e.g., meat-based wet food with minimal carbs) helps maintain stable glucose levels and reduces the need for insulin.
Obesity and Weight Control
Carbohydrate-heavy, high-GI dry foods can contribute to weight gain and fat storage.
A low-GI diet reduces fat accumulation by preventing excessive insulin release.
Why GI Is Less Important for Cats Than Humans
Cats don’t rely on carbohydrates for energy; they primarily use protein and fat.
They have continuous gluconeogenesis (making glucose from protein), so dietary carbs aren’t necessary.
Most high-protein, meat-based diets naturally have a low GI, making GI less of a concern unless feeding carb-heavy foods.
For cats, instead of focusing on GI values, it's better to prioritize a high-protein, low-carb diet (ideally wet or raw food) to support stable blood sugar and overall health. If a cat must eat some carbs (like in kibble), choosing lower-GI options can help reduce blood sugar spikes, especially for diabetic or overweight cats.
"Although cats have a limited ability to process carbohydrates, they can still absorb simple sugars. High-GI foods (e.g., rice, potatoes, corn) can lead to rapid blood sugar spikes, which can contribute to insulin resistance and diabetes. Low-GI foods (e.g., lentils, peas, chickpeas) cause a slower, more gradual rise in blood sugar, which is better for diabetic or overweight cats." If cats cannot process, I assume, complex complex carbohydrates, what difference would it make if they are low or high GI?
You're asking a great question, and it gets to the heart of how carbohydrates interact with a cat’s metabolism. If cats are not well-adapted to digesting complex carbohydrates, why would the glycemic index (GI) of a food matter? Let’s break it down:
1. Cats and Carbohydrate Digestion
Cats lack key digestive enzymes, like amylase in saliva, and have a shorter digestive tract, making them less efficient at breaking down complex carbohydrates (like starches and fibers).
However, they can absorb simple sugars (like glucose) directly in the intestines and into the bloodstream.
2. Why Does GI Matter If Cats Don't Need Carbs?
When carbs are included in a cat’s diet (like in commercial foods), some are partially digested and broken down into absorbable sugars.
High-GI carbs (like rice, potatoes, corn) break down quickly, causing rapid glucose absorption and a spike in blood sugar.
Low-GI carbs (like lentils, peas, chickpeas) break down more slowly, resulting in a gradual release of glucose into the bloodstream.
3. The Impact on Blood Sugar and Insulin
Even though cats do not require carbohydrates, their bodies will still react to sugar in the bloodstream:
A rapid blood sugar spike (from high-GI foods) can trigger a strong insulin response, potentially leading to insulin resistance over time (a key factor in feline diabetes).
A gradual rise (from low-GI foods) results in less stress on insulin regulation, reducing the risk of diabetes and obesity.
4. The Bigger Issue: Should Cats Eat Any Carbs?
Ideally, cats shouldn’t eat a diet high in carbohydrates at all, since they rely on protein and fat for energy.
However, many commercial dry cat foods contain 30-50% carbohydrates because they're used as cheap fillers and binding agents.
If carbs must be in the diet, low-GI options are slightly less harmful because they minimize blood sugar spikes.
If a cat is eating a biologically appropriate diet (high-protein, low-carb), the glycemic index doesn't matter because they aren't consuming enough carbs for it to have an effect. But in carb-containing diets (like kibble), GI matters because it influences how much the unnecessary carbs impact blood sugar and insulin.
So, what's better for the diabetic cat? A food with 0% carbs or a food with LG carbs?
For a diabetic cat, the best choice is a food with 0% carbohydrates (or as close to zero as possible).
Cats have no dietary requirement for carbohydrates—they thrive on protein and fat.
Every bit of carbohydrate requires insulin regulation, which is problematic for diabetic cats.
Even low-GI (LG) carbs still raise blood sugar, just at a slower rate. But since diabetic cats struggle with glucose regulation, any unnecessary rise in blood sugar is a burden on their system.
Best Diet for a Diabetic Cat:
✅ High protein (~50% or more on a dry matter basis)
✅ High fat (~30% or more)
✅ Low to no carbohydrates (~5% or less, ideally 0%)
✅ Canned, raw, or freeze-dried food (since most kibble is high in carbs)
❌ Dry kibble (even "grain-free" ones still contain starchy fillers like potatoes or peas)
❌ Any food with high-GI carbs (like rice, corn, potatoes, wheat)
❌ Even low-GI carbs (like lentils, chickpeas, peas) are unnecessary and should be minimized
A food with 0% carbs is always better than a food with low-GI carbs for a diabetic cat. No carbs = no blood sugar spikes = less insulin needed.
"Young Again", a brand of dry cat food claims 0% carbs, crude protein 57.9% and crude fat 28.8%. Is this believable?
"Young Again" is one of the few dry cat foods that claims to be truly zero-carb, which is unusual because most kibble requires starch as a binder. The 57.9% crude protein and 28.8% crude fat sound like a high-quality, species-appropriate macronutrient profile for cats. However, the 0% carbohydrate claim is worth scrutinizing.
Is 0% Carbs in Dry Cat Food Possible?
Yes, but only if the food uses alternative binders instead of traditional starches (like rice, potatoes, or peas).
Most dry kibble needs some form of starch (20–50%) to hold the kibble shape.
Young Again claims to use gelatin and other non-carb binders instead of starch.
If they achieve this, the carb content would be extremely low—close to 0%.
How to Verify the Carbohydrate Content
To check if their claim is reasonable, use the Guaranteed Analysis (GA) method:
Add up the known macronutrients from the GA:
Ash: 6% (estimated since most dry foods contain 5-8%)
Subtract from 100% to estimate carbohydrates:100−(57.9+28.8+4+6)=3.3% carbohydrates100 - (57.9 + 28.8 + 4 + 6) = 3.3\% \text{ carbohydrates}100−(57.9+28.8+4+6)=3.3% carbohydratesThis suggests that Young Again likely has ~3% carbs, not truly 0%, but still extremely low compared to most kibbles.
Is It a Good Choice for Diabetic Cats?
✅ Much better than traditional kibble (which often contains 20-50% carbs).
✅ High protein and fat fit a cat’s natural diet.
✅ Close to zero carbs, making it suitable for diabetic cats.
⚠️ Still dry food—and moisture is crucial for diabetic cats to support kidney function and overall hydration.
⚠️ Processing methods may still impact nutrient bioavailability compared to raw or canned food.
The zero-carb claim is likely exaggerated, but the actual carb content (~3%) is still exceptionally low for dry food.
If you must feed kibble, Young Again is one of the best options for diabetic cats.
However, a high-protein wet or raw diet is still superior due to better hydration and natural digestion.
Young Again crude analysis of "Zero Mature" is 0.
If Young Again’s "Zero Mature" formula lists 0% carbohydrates in its Guaranteed Analysis (GA), it’s important to double-check how that number is determined.
Guaranteed Analysis vs. As-Fed vs. Dry Matter Basis
Guaranteed Analysis (GA) doesn’t always list carbohydrates because they aren’t required on pet food labels.
True carbohydrate content is usually calculated by subtracting protein, fat, moisture, and ash from 100%.
Let's Recalculate the Carbs (Based on the "Zero Mature" formula's GA)
Ash: 6% (estimated, since most dry foods contain 5-8%)
Estimated carb content:100 - (57.9 + 28.8 + 4 + 6) = 3.3\% \text{ (not truly 0%)}
So, while they may claim 0% "starch-based" carbs, there is likely a small amount of fiber or other non-starch carbohydrates present.
🔹 If all digestible carbs (starches & sugars) are removed, the food may still contain indigestible fiber, which doesn’t contribute to blood sugar spikes.
🔹 Some labeling loopholes allow pet food companies to round down small carb percentages to zero if they’re low enough.
Bottom Line for a Diabetic Cat
✔ One of the lowest-carb kibbles available—great for diabetic cats who refuse wet/raw food.
✔ High protein and fat, making it far better than standard dry food.
⚠ Still dry food—hydration is crucial, especially for diabetic and senior cats.
👉 Best case: If your diabetic cat must eat kibble, Young Again "Zero Mature" is an excellent choice. But if possible, a high-protein wet or raw diet is still the ideal option.
You left out Crude Fiber = 3.3%.
Good catch! Let's recalculate with Crude Fiber = 3.3% included.
Young Again "Zero Mature" Guaranteed Analysis (GA) Breakdown:
Now, using the formula to estimate carbohydrate content:100−(57.9+28.8+4+6+3.3)=0100 - (57.9 + 28.8 + 4 + 6 + 3.3) = 0%100−(57.9+28.8+4+6+3.3)=0
So, Is It Truly Zero-Carb?
Yes, based on GA calculations, it appears to be legitimately 0% digestible carbs.
Crude fiber (3.3%) is an indigestible carbohydrate, meaning it doesn't contribute to blood sugar spikes.
No starches, sugars, or digestible carbs appear to be in the formula.
✅ This is likely one of the only truly zero-carb kibbles.
✅ Ideal for diabetic cats compared to traditional dry foods.
⚠ Still dry food—moisture is crucial, especially for diabetic cats.
👉 Best Option for Diabetic Cats Who Must Eat Kibble. But wet or raw diets are still better for hydration and overall health.
Is crude fiber used to lower the glycemic index if it is eaten with carbs?
Yes, crude fiber can help lower the glycemic index (GI) of a food when eaten with carbohydrates, but its impact on cats is different from that in humans.
How Fiber Lowers Glycemic Index (GI) in General
In species that digest carbohydrates more efficiently (like humans or dogs), fiber helps:
Slow down digestion by delaying the breakdown of carbs into glucose.
Reduce blood sugar spikes by slowing the absorption of glucose into the bloodstream.
Improve insulin sensitivity by moderating post-meal blood sugar responses.
Does Fiber Lower GI in Cats?
For cats, the effect is less pronounced because:
Cats have a limited ability to digest carbohydrates, so they naturally experience less glucose fluctuation than omnivores.
Fiber isn't digested by cats, but it can slow carbohydrate absorption if carbs are present in their diet.
In a truly zero-carb food like Young Again "Zero Mature", crude fiber wouldn't impact GI at all, since there's no starch or sugar to affect blood glucose.
So, Why Is Crude Fiber in Cat Food?
Weight management – Fiber can create a feeling of fullness, helping with appetite control.
Digestive health – Certain fibers (like beet pulp or cellulose) can promote stool regularity.
Diabetes management (only in carb-containing diets) – In foods with carbs, fiber can reduce blood sugar spikes by slowing glucose absorption.
🔹 If carbs are present, fiber can help moderate GI and slow glucose absorption.
🔹 If no carbs are present, fiber does not affect GI—it's just an indigestible component that supports digestion.
🔹 In a true zero-carb food (like Young Again "Zero Mature"), fiber does not impact blood sugar at all.
👉 For diabetic cats, the best approach is to avoid carbs altogether, making the glycemic index irrelevant!
