What Is Pet Diabetes? Diabetes in Dogs & Cats Explained

If your dog or cat has just been diagnosed — or you're trying to understand a worrying set of symptoms — this is the plain-English explanation of what diabetes actually is, without the jargon.

What is diabetes mellitus?

Diabetes mellitus is a condition where the body can't move glucose (sugar) from the blood into its cells for energy. That job is done by insulin, a hormone made by the pancreas. In diabetes, there either isn't enough insulin, or the body has stopped responding to it properly. Glucose then builds up in the bloodstream while the cells effectively starve — which is why a diabetic pet can lose weight even while eating well. In dogs, damage to the pancreas from inflammation may also affect the insulin-producing cells; our guide to pancreatitis and diabetes in dogs explains what the research currently suggests.

Why does it cause the symptoms it does?

The classic signs all trace back to that build-up of glucose. Excess glucose spills into the urine and drags water with it, so your pet urinates more and drinks more to keep up. The cells' hunger for energy drives increased appetite, while the body breaking down fat and muscle for fuel causes weight loss. Understanding this makes the symptoms far less frightening — they're all one process.

How is it different in dogs and cats?

This matters for treatment. Dogs usually have a form where the pancreas makes little or no insulin, so they need insulin injections for life — much like type 1 diabetes in people. Our guide to whether diabetes in dogs is an autoimmune condition explains what the emerging research suggests. Cats more often have a form driven by insulin resistance, frequently linked to weight, closer to type 2 — which is why weight management and a low-carbohydrate diet are so powerful, and why some cats can even go into remission. Our guide to how common diabetes is in cats in the UK puts the current figures and risk factors in context. Same disease name, genuinely different journeys.

What does managing it involve?

Three things, done consistently: insulin (usually twice daily), a suitable and consistent diet, and monitoring so you and your vet can see whether it's working. It feels overwhelming on day one and becomes routine within weeks.

Mello is built to make that daily tracking simple and turn it into something your vet can actually use.

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Caring for a diabetic cat, day to day

If your cat has been newly diagnosed with diabetes, the core management is the same — insulin, diet, monitoring — but the daily realities differ from dogs. Here's what you need to know.

Why cats' diabetes is different

Cats are obligate carnivores with a metabolism built around high protein and fat, not carbohydrate. Type 2 diabetes is far more common in cats than dogs and is often driven by insulin resistance rather than pancreatic failure — which means dietary changes can be transformative. Some cats, especially if caught early and treated promptly with low-carbohydrate food and close glucose control, go into remission and stop needing insulin — a minority rather than most, and not permanently for everyone. For dogs, plan for insulin for life. The one real exception is an entire bitch whose diabetes was driven by the hormones of her season: spaying is recommended in that case and can allow the diabetes to resolve, which is why vets ask whether a diabetic dog is neutered.

The litter tray as a diagnostic tool

One of the easiest early warning signs is in the litter box: increased urination and thirst are diabetes hallmarks, and you'll often notice them there first. After diagnosis, monitor:

• Urine volume: More is expected with high glucose initially, then should normalise with treatment
• Thirst: Excessive drinking (more than 2-3 days running) warrants a vet call
• Appetite: Cats sometimes go off food during adjustment; tell your vet if it lasts more than a day or two

Cats hide illness: what to watch for

Cats mask problems much more than dogs. Even if they seem fine, watch for:

• Subtle appetite changes: A few missed meals hidden in normal variability, or pickiness that shifts day to day
• Activity shifts: Sleeping more, playing less, or changes in jumping or climbing (weakness from poor glucose control)
• Grooming: Neglected grooming can indicate malaise
• Litter box habits: Constipation, diarrhoea, or excessive litter clumping changes

Early intervention on small changes prevents them becoming big problems.

Managing insulin injections with a cat

Cats are often less enthusiastic about handling than dogs. Inject quickly, calmly, and with minimal restraint — fight or stress raises glucose and distorts readings. Most cats adapt within days. Reward immediately after with a favourite treat to build positive association.

Pro tip: Many diabetic cats thrive on a schedule. Same time, same place, same comfort routine. The ritual becomes less stressful for both of you.

Feeding routine: the cat-specific challenge

Cats are often pickier eaters than dogs and may be less motivated by routine meal timing. Yet consistent feeding is crucial for insulin coordination. Strategies:

• Timed feeders: Automate meal delivery at set times so you're not juggling schedules
• Portion control: Cats shouldn't free-feed; measure meals so you know intake for insulin calculations
• Low-carb matters more: A picky cat on a suboptimal but eaten low-carb diet is better off than refusing a perfect diet. Work with your vet if your cat refuses the first option
• Transition slowly: 1-2 week food changes work better than rapid switches

The remission possibility

Here's something unique to cats: if you catch diabetes early, feed low-carb aggressively, and achieve good glucose control quickly, your cat might go into remission — stopping insulin entirely while maintaining normal glucose. This isn't a cure; the cat remains diabetic and must be monitored forever. Remission can reverse if diet slips or weight rises. But it's real and worth pursuing.

Early consistency is what gives remission its best chance. About a quarter of the cats who achieve it do so in the two to three months after diagnosis, and most of the rest within six months — so the first half-year is the window that matters, not the first few weeks. Diet is a large part of it: see feeding a diabetic cat for the carbohydrate target and how to work it out from a label, rather than a figure quoted without its units.

Monitoring: the cat angle

Cats, especially, show stress hyperglycaemia — their glucose shoots up at the vet clinic due to anxiety. This is normal feline biology. Home monitoring is invaluable because you see your cat's true glucose, not their stressed reading. Build comfort with testing at home so you're not chasing phantom highs from clinic stress.

When to call your vet

The same rules apply as dogs — high readings, low readings, pattern changes — but also watch for behaviour changes that might suggest trouble:

• Refusing meals for more than a day
• Sudden lethargy or wobbly gait
• Vomiting (can indicate hypoglycaemia or other problems)
• Increased vocalization or agitation (some cats signal distress this way)

Life expectancy and quality

Quality of life for a well-managed diabetic cat is generally good, and cats in remission often go a long time without insulin — remission is associated with longer survival. It is not the same as a cure, though: the current consensus puts the median length of remission at about four to five months, with 13% to 40% of cats relapsing. For what the published survival figures do and do not tell you, see how long a diabetic pet lives.

Sources

The pages below were each opened and checked before being listed here, and anything that could not be opened was left off rather than guessed at.

• Diabetes Mellitus in Dogs and Cats — MSD Veterinary Manual, reviewed May 2024, updated May 2026. The difference between the species: remission is possible in cats, while canine diabetes is generally lifelong, and obesity drives insulin resistance in both.
• Diabetes mellitus: diagnosis and treatment — Vet Times, Emma Gerrard, reviewed by Rebecca Norton BVetMed MRCVS, 2020. The type-1-like and type-2-like framing used here, and that spaying can allow a season-driven diabetes in an entire bitch to resolve.
• Diabetic Remission (Section 9) — 2026 AAHA Diabetes Management Guidelines for Cats, 2026. The definition of remission, that about a quarter of the cats who reach it do so within two to three months, and that most of the rest do so within six.
• Dietary Management (Section 8) — 2026 AAHA Diabetes Management Guidelines for Cats, 2026. The dietary direction for cats: reduced carbohydrate, high protein, canned preferred over dry.
• 2025 iCatCare consensus guidelines on the diagnosis and management of diabetes mellitus in cats — Journal of Feline Medicine and Surgery 27:1–37, 2025. That stress hyperglycaemia in cats can be of any size, which is why a single high reading at the practice is not a diagnosis.