⚠ Important: Hypoglycemia (low blood sugar from too much insulin) is a medical emergency. Signs include weakness, trembling, seizures, and collapse. If you suspect hypoglycemia in your diabetic cat, rub corn syrup or honey on their gums and get to an emergency vet immediately.

Diabetes in Cats: Symptoms, Insulin & Dietary Management

By Sarah Bennett, Certified Animal Nutritionist

Feline diabetes mellitus has become increasingly common, mirroring trends seen in human medicine as modern cats lead more sedentary, calorie-rich lives. The good news is that with the right treatment protocol — particularly a high-protein, low-carbohydrate diet paired with appropriate insulin therapy — many cats can achieve diabetic remission, meaning they no longer require insulin at all. This is a realistic goal for a significant proportion of newly diagnosed cats, and it makes early, aggressive management all the more worthwhile.

What Is Feline Diabetes?

Cats almost exclusively develop Type 2 diabetes mellitus, characterized by insulin resistance (the body's cells fail to respond normally to insulin) combined with a progressive decline in the pancreatic beta cells that produce insulin. This is distinct from Type 1 diabetes (autoimmune destruction of beta cells), which is rare in cats.

The disease is more common in middle-aged to older cats, male cats, neutered cats, and overweight or obese cats. Indoor lifestyle, high-carbohydrate dry food diets, and physical inactivity are significant contributing risk factors — all modifiable with the right approach. Breed predispositions exist; Burmese cats have a notably higher risk, particularly in Australia and the UK.

Symptoms of Diabetes in Cats

The classic signs of feline diabetes are well-defined, though they can be subtle early in the disease:

Polyuria and polydipsia (PU/PD): Excessive urination and drinking are the hallmark signs. High blood glucose causes glucose to spill into the urine, pulling large volumes of water with it. You may notice the litter box is wetter than usual, or that your cat visits the water bowl repeatedly.
Weight loss despite increased appetite: When cells can't use glucose effectively, the body breaks down fat and muscle for energy, causing weight loss even as the cat eats more (polyphagia). This paradox of eating more while losing weight is a classic diabetic presentation.
Plantigrade stance: One of the most distinctive signs in cats. Diabetic neuropathy damages peripheral nerves, causing weakness in the hindlimbs and making the cat walk flat-footed, with hocks touching the ground instead of walking on their toes. This is sometimes called "diabetic neuropathy hind limb weakness." It can be partially or fully reversible with good glucose control.
Lethargy and reduced activity: Cats feel unwell when blood glucose is persistently elevated and often become less active and playful.
Poor coat condition: An unkempt, greasy, or dull coat is a nonspecific but common sign of chronic illness including diabetes.
Vomiting: May occur, particularly with diabetic ketoacidosis (DKA), a serious acute complication requiring emergency hospitalization.

Diagnosis

Diagnosis requires demonstrating persistently elevated blood glucose alongside glucosuria (glucose in the urine). A single elevated blood glucose is not sufficient — cats are notorious for stress hyperglycemia, meaning a vet visit alone can push glucose into diabetic ranges in a healthy cat. Fructosamine levels (reflecting average blood glucose over the past 2–3 weeks) are very helpful in distinguishing true diabetes from stress hyperglycemia. A urinalysis helps confirm glucosuria and screen for concurrent urinary tract infection, which is common in diabetic cats.

Insulin Therapy

Nearly all diabetic cats require insulin therapy, at least initially. Several insulin types are used in cats:

Glargine (Lantus): A long-acting basal insulin that has become the preferred choice for cats in many countries. It maintains more stable blood glucose levels compared to older insulins and is strongly associated with achieving remission when combined with dietary management. Typically given every 12 hours.
ProZinc (PZI): A veterinary-approved protamine zinc insulin, also long-acting, with a good track record in cats.
Caninsulin/Vetsulin (porcine lente): Shorter-acting, requires twice-daily dosing; still used but less preferred than glargine for achieving remission.
Detemir (Levemir): Sometimes used in cats; more potent than glargine on a unit-per-unit basis, requiring careful dosing adjustments.

Dosing always starts conservatively (typically 0.5–1 IU twice daily for glargine) and is adjusted based on home glucose monitoring or serial blood curves. Home glucose monitoring using a human glucometer calibrated for cats, or a continuous glucose monitor like the Libre, has transformed feline diabetes management — giving owners real-time data to guide dosing and detect hypoglycemia early.

High-Protein, Low-Carbohydrate Diet: The Dietary Revolution

Diet is arguably as important as insulin in managing feline diabetes, and it may be the most powerful tool for achieving remission. Cats are obligate carnivores with a metabolic physiology evolved for a meat-based, minimal-carbohydrate diet. Their insulin secretion is fundamentally different from omnivores — carbohydrates cause a much larger relative glucose spike in cats than in dogs or humans.

Transitioning a diabetic cat to a high-protein, low-carbohydrate diet dramatically reduces the postprandial glucose load, lowering insulin requirements and creating the conditions for beta cell recovery. The target is food with less than 10% of calories from Science Behind Grain vs Grain-Free">carbohydrates (ideally under 5%), and greater than 40% of calories from protein. Most prescription diabetic diets (Royal Canin Diabetic, Hill's m/d) meet this criterion. Many high-quality grain-free wet foods also fall within acceptable ranges — check nutritional labels carefully. Dry food, even "premium" varieties, is almost universally too high in Science Behind Grain vs Grain-Free">carbohydrates for diabetic cats.

Recommended: Zooplus stocks Royal Canin Diabetic and Hill's m/d wet food formulations specifically designed for diabetic cats. Switching to wet food alone often reduces insulin requirements significantly — discuss any diet change with your vet before adjusting insulin doses.

The Possibility of Remission

Diabetic remission — where a cat no longer requires insulin to maintain normal blood glucose — is achievable in approximately 50–90% of newly diagnosed cats treated with long-acting insulin (especially glargine) and a low-carbohydrate diet. Remission is more likely in cats diagnosed early, before prolonged beta cell exhaustion, in cats that achieve healthy body weight, and in cats managed with dietary change alongside insulin.

Remission is defined as maintaining normal blood glucose without insulin for at least 4 consecutive weeks. Even cats that achieve remission can relapse, so periodic monitoring is essential. Maintaining the low-carbohydrate diet indefinitely reduces relapse risk significantly.

Weight Management and Ongoing Monitoring

Obesity is a primary driver of insulin resistance. Gradual, supervised weight loss significantly improves glucose control. Rapid weight loss in cats risks hepatic lipidosis, so any weight reduction plan should be gradual and veterinarian-guided. Physical activity — encouraged through play sessions — also improves insulin sensitivity.

Long-term monitoring includes periodic fructosamine measurements, home glucose curves, assessment of body weight, and annual or biannual blood chemistry panels to detect complications. Hypertension, urinary tract infections, and pancreatitis are all more common in diabetic cats and require vigilance.

Key Takeaways

Cats develop Type 2 diabetes; obesity, sedentary lifestyle, and high-carb dry food are major risk factors.
Classic signs: excessive drinking/urinating, weight loss despite eating, plantigrade (flat-footed) hindlimb stance.
Glargine (Lantus) is currently the preferred insulin for achieving remission in cats.
A high-protein, low-carbohydrate wet food diet is essential and can dramatically reduce insulin needs.
Up to 90% of newly diagnosed cats managed aggressively can achieve diabetic remission.
Home glucose monitoring is strongly recommended for safe and effective diabetes management.

References

Roomp K, Rand JS. "Intensive blood glucose control is safe and effective in diabetic cats using home monitoring and treatment with glargine." Journal of Feline Medicine and Surgery. 2009;11(8):668-682. PMID: 19481480
Bennett N, et al. "Comparison of a low carbohydrate-low fiber diet and a moderate carbohydrate-high fiber diet in the management of feline diabetes mellitus." Journal of Feline Medicine and Surgery. 2006;8(2):73-84. PMID: 16275173