Cats caught early can go into remission and, with their vet's agreement, come off insulin altogether. That window is measured in months from the first symptom, which is why what you noticed at the water bowl this week matters more than it feels like it should.
The reason it goes unnoticed is that nothing looks wrong. A cat drinking more is not a cat that seems ill, and unless you empty the litter tray yourself you may never register how much heavier it has become.
Blood sugar climbs until the kidneys can no longer hold it back, somewhere around 250 mg/dl, and from there it pulls water into the bladder with it. Everything else on this page follows from that leak.
The list below runs in the order the disease tends to reveal itself. Everything in the first group is something you could plausibly explain away as your cat getting older. From the plantigrade stance onwards, you can't.
12 Signs Your Cat May Have Diabetes
Diabetic cat symptoms tend to show up in waves. Early signs of feline diabetes look like normal cat behaviour with the volume turned up. The later ones (from plantigrade stance to fatty liver) are harder to ignore.
That is why they are grouped below by when they tend to appear rather than by how serious they are.
The Early Warning Signs
1. Increased thirst
A diabetic cat's blood sugar climbs high enough to overflow the kidneys' filtration capacity.
Thirst that follows has a clinical name, polydipsia. In practice it looks like a bowl needing a refill every day when it used to last three, or a cat that starts working the taps, shower trays and plant saucers it previously walked past.
2. Increased urination
Polyuria comes from the same kidney overflow as the polydipsia above.
Polyuria is the other half of the same leak. The litter tray is where you can measure it: count clumps for three days, because a jump from two or three a day to six or more is data your vet can use.
3. Increased appetite without weight gain
Glucose isn't reaching the cells, so the body keeps signalling hunger even when blood sugar is high.
Your cat eats more but doesn't fill out, with appetite climbing while body weight quietly drifts down.
4. Subtle weight loss
When cells can't access glucose, the body breaks down fat and protein for energy.
Scales beat eyes here. A coat hides a great deal, and by the time ribs are obvious a tenth of the body has usually gone. Weigh monthly by standing on kitchen scales holding the carrier, then again without it.
Middle-Stage Signs
5. Lethargy
Cells that cannot get at glucose leave a cat short of fuel. The tell is a change in what your cat still bothers to get up for, such as skipping the window ledge at dusk or no longer meeting you at the door.
Indoor cats can mask lethargy because their baseline activity is already low, so compare your kitty against their usual behaviour rather than a generic standard.
6. Poor coat quality
Diabetic cats often develop oily or dandruffy coats once grooming drops off. A scurfy coat has other causes worth excluding first, including Cheyletiella mites and hyperthyroidism in an older cat.
Grooming drops off and the skin's environment changes with altered glucose handling. The coat picks up the change before any blood test would.
7. Vomiting
As blood glucose climbs further, gastroparesis (slowed stomach emptying) and nausea kick in.
Vomiting only counts here alongside the other signs; on its own it points somewhere else entirely.
8. Unusual Behavior
Some cats turn irritable from the chronic blood sugar swings, while others withdraw and hide.
Either pattern, paired with earlier signs, means feline diabetes is progressing. Litter box behaviour often changes alongside the increased urination.
Late or Emergency Signs of Cat Diabetes
9. Plantigrade stance
Watch your cat cross a hard floor. Hocks flat to the ground instead of up on the pads is the classic neuropathy posture, and it needs an appointment rather than monitoring. It commonly improves once glucose is controlled, over months rather than weeks, and not in every cat.
10. Hind leg weakness
Hind leg weakness is a milder form of the same neuropathy.
Jumping is where it shows first. A cat that used to reach the worktop in one movement starts pausing, choosing a lower route, or not bothering.
11. Loss of appetite and rapid weight loss
The picture flips at this point. Eating more while slowly losing weight is chronic; eating nothing while losing weight quickly is urgent.
Fatty liver can develop quickly in cats who stop eating, so book a vet visit the same day if appetite drops and weight loss accelerates together.
12. Diabetic ketoacidosis (DKA)
DKA is the emergency. Fat breakdown accelerates and ketones build up in the bloodstream.
Blood turns acidic, and your cat needs the ER tonight rather than a routine vet visit. Watch for the red flags below.
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Severe lethargy or collapse as the body becomes acidic
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Fruity or acetone-smelling breath, which comes from ketones rather than the sugar itself
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Rapid breathing tied to runaway blood sugar
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Repeated vomiting on top of the urgent weakness
Why Hydration Matters So Much for a Cat With High Blood Sugar
Several of the cat diabetes symptoms above share a single physiological driver. Glucose floods the body. Kidneys overflow and water follows the sugar out, which is why polyuria leads directly to dehydration.
Water stops being a background habit here. A cat leaking fluid through its kidneys has to replace it, and going short compounds everything else on this page.
Water has to be available on your cat's schedule rather than yours, because the losses run around the clock.
The KittySpout Wireless Fountain 2.0 holds 4 litres in a stainless reservoir. Empty, wash and refill on your normal schedule.
A 3-layer activated carbon filter removes 99.9% of chlorine and 95% of heavy metals on KittySpout's published figures, which mainly shows up as water your cat is happier to drink. The pump runs at under 25 decibels, quieter than a whisper.
Dr. Anna Maria Wolf DVM recommends it by name, the 365-day money-back guarantee covers the full year, and 96% of KittySpout customers report more drinking after the switch.
If you've been turning the tap on for your kitty every morning, this is the hydration upgrade you want.
Cat Diabetes Risk Scorecard
Run this 6-factor scorecard for your cat to assess the risk factors that matter. Add the points then read the risk factors band below.
It's a guide for where your attention should sit. Higher scores mean closer monitoring of body weight, hydration, and appetite.
What Your Score Means
Low (0 to 4)
Your cat sits at baseline diabetes risk, and an annual vet visit is enough.
Keep an eye on these risk factors from month to month:
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Body weight on the same scale
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Appetite changes versus normal
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Water bowl drinking patterns
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Litter box frequency and volume
Watch (5 to 8)
Slightly elevated risk. Weigh monthly and swap one daily meal from dry food to a low-carb option.
Add a food puzzle to feeding time, and schedule 10 minutes of play twice a day to lift activity and support hydration in your kitty.
Elevated (9 to 12)
Book an appointment to talk through diet and weight. This is the band where doing nothing has a cost.
Switch fully to a low-carb diet if practical, and ask your veterinarian about a baseline blood test for glucose and a urinalysis.
High (13+)
High-priority territory. Book a vet visit within two weeks.
Ask about a fructosamine test, a urinalysis, and possibly a blood glucose curve. Address weight first if obesity is a factor, because even a modest, steady loss shifts the picture.
Frequently Asked Questions
Can Cat Diabetes Be Reversed?
Sometimes, yes. Early insulin plus a low-carbohydrate diet gives the best odds of coming off injections altogether.
Cats treated promptly and on a low-carbohydrate diet have the best chance of remission. Glargine insulin has produced high remission rates in published work, though those figures come from small studies. SGLT2 oral medications give good glucose control, with remission data still emerging.
Are Indoor Cats at Higher Risk?
Yes. Indoor cats are less active and more prone to obesity, both of which raise diabetes risk. The fix isn't moving them outside; add play and switch to structured feeding, since weight is the factor that moves risk most.
What Does Diabetic Cat Urine Smell Like?
Sweet or slightly fruity. Glucose passing into the urine produces a distinctive smell. A urine glucose dipstick from your vet is the usual check, and home blood glucose monitoring is worth asking about, though your vet should set it up with you and show you the technique before you rely on the readings.
When Is It an Emergency?
Diabetic ketoacidosis is the emergency case. Watch for any of the red flags below.
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Severe lethargy as ketones build up
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Repeated nausea or sudden loss of appetite
- Fruity-smelling breath signalling acidosis
- Rapid breathing tied to runaway blood sugar
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Collapse or unresponsiveness
Get to the ER tonight, not a routine vet visit next week. Bring along recent body weight and feeding notes if you can grab them on the way out.
Hypoglycaemia is a separate emergency and it happens in cats already on insulin. Ring the clinic if yours is weak, wobbly or twitching. Their instruction is usually honey on the gums; never force liquid into a cat that isn't fully conscious, and never adjust the next dose without asking.
Can Wet Food Prevent Diabetes?
It lowers risk without removing it. The active ingredients are a lean cat and a low carbohydrate load, and canned food happens to deliver both.
Does Plantigrade Stance Go Away?
Often yes, with treatment. Diabetic neuropathy reverses in many cats once blood sugar stabilises, typically over several months. In a smaller number it persists, but quality of life stays good if glucose stays controlled.