Cats are generally considered senior starting around age 10, though the Feline Veterinary Medical Association notes some cats show senior-level changes earlier depending on breed and health history, according to PetMD. Their nutritional needs shift meaningfully at this stage — not just “less food,” but a different balance of nutrients entirely.
What Actually Changes
- Calorie needs drop. An adult cat needs roughly 20 calories per pound daily; a senior cat typically needs closer to 15 calories per pound, reflecting a slower metabolism and lower activity level. Some older seniors are the exception and actually need more calories to maintain a healthy weight — which is exactly why a vet-guided plan matters more than a generic rule.
- Protein still matters. Along with carbohydrates, quality protein helps senior cats maintain body weight and energy levels even as calorie needs fall.
- Phosphorus needs to drop. As kidney function naturally declines with age, cats become less able to clear excess phosphorus, making lower-phosphorus diets a common recommendation — particularly relevant since kidney disease is one of the most common senior cat conditions.
- Omega-3s and antioxidants help more. Omega-3 fatty acids support skin, coat, and joints while reducing inflammation. Antioxidants — vitamins E, C, A, carotenoids, and selenium — help offset cellular damage that accumulates with age.
- Carnitine supports muscle and heart. This nutrient plays a role in maintaining muscle mass and heart function in older cats, both areas prone to decline.
- Fiber supports digestion. Aging digestive systems often benefit from the added fiber found in senior-formulated diets.
Hydration Deserves Its Own Attention
Senior cats often need to drink more water than younger cats to help protect kidney function — but cats are notoriously poor self-hydrators to begin with. Water fountains (many cats prefer moving water) and hydration-boosting supplements or wet food can meaningfully increase intake without relying on a cat to simply drink more from a bowl.
Signs of a Nutrient Deficiency
Watch for a cluster of these signs rather than any single one in isolation:
- Dull coat or noticeable fur loss
- Diarrhea or constipation
- Vomiting
- Low energy or reduced appetite
- Unexplained weight loss or gain
- Behavioral changes such as new aggression, fearfulness, or confusion
- Infections that keep recurring
Several of these overlap with signs of other senior cat conditions (kidney disease, hyperthyroidism, dental pain), which is exactly why a vet visit — not a food swap — should be the first response.
Before You Switch Foods
As with dogs, don’t switch a senior cat to a new formula based on age alone. A full veterinary evaluation — physical exam, diet history, bloodwork, and urinalysis — identifies what your specific cat needs, since an underweight senior with early kidney disease and an overweight senior with arthritis need very different diets despite both being “senior cats.”
Source: PetMD — Senior Cat Nutrition: What To Know for Your Cat.
Photo: “Stray Cat” by Dwight Sipler, licensed under CC BY 2.0.