Adapting the Diet of Senior Dogs and Cats
The senior stage of dogs and cats brings physiological changes that require adjustments to their diet. As they age, their metabolism slows down, they lose muscle mass, and they may develop dental or digestive problems.
PETS
9/24/20257 min read
The senior stage of dogs and cats brings physiological changes that require adjustments to their diet. As they age, their metabolism slows down, they lose muscle mass, and they may develop dental or digestive problems. A proper diet during these golden years helps maintain their ideal weight, the health of vital organs, and a good quality of life. Below, we detail the key aspects for identifying your pet's senior age, the typical changes of old age, the essential nutrients during this stage, and practical recommendations for adapting their diet gradually and safely.
When Is Your Pet Considered Senior?
The exact age to consider a dog or cat "senior" varies by species and size. In general, dogs are considered older adults around 7–8 years of age (1). However, large breeds age sooner than small ones: for example, a large dog can be senior from 6–7 years old, while a small breed dog may take 8–9 years to reach that stage (1, 2). Cats, on the other hand, typically enter the senior stage around 7–10 years of age (some sources point to a typical age of 10–11 years) (3, 4). These ages are just a guide: the most important thing is to observe the signs of aging (decreased activity, change in appetite, joint stiffness, etc.) and consult a vet, as physiological age can differ from chronological age.
Physiological Changes in Old Age
With age, several bodily adaptations occur in dogs and cats:
Weight and Musculature: Senior animals tend to have a slower metabolism and reduced physical activity (5). This favors the accumulation of body fat and the loss of muscle mass. Muscle atrophy is common, so they require more high-quality protein to compensate (see Nutrition section).
Slow Metabolism: Lower metabolic efficiency means they burn fewer calories. Therefore, they tend to gain weight if their previous portion sizes are maintained. Controlling the daily amount and adjusting calories is key (5).
Dental Health: Teeth and gums often deteriorate. Gingivitis and tooth loss are common (6). This makes it difficult to chew dry or hard food. You should offer softer foods, soaked kibble, or wet food as recommended by your vet, and brush their teeth periodically.
Weaker Digestion: Digestive function is affected by age. Nutrient absorption decreases, and intestinal motility is often slower. This is why food should be easier to digest and contain a bit more fiber (6, 7). The risk of constipation or other intestinal disorders also increases.
Mobility and Joints: Many older dogs and cats develop arthritis or other joint problems. You may notice a slight limp, stiffness when getting up, or reluctance to climb stairs (8). Joint pain reduces physical activity, which worsens muscle loss and obesity.
Changes in Senior Cats: From around 10 years old, many cats lose weight due to common old-age diseases (hyperthyroidism, subclinical kidney or heart failure) (9). Additionally, older cats have a lower capacity to digest proteins and fats (10). Despite this, it's not advisable to overly restrict protein in their diet, as they need it to maintain their muscle mass. Ideal diets limit phosphorus (for kidney health) without excessively reducing protein (10).
In short, senior dogs and cats require food that compensates for muscle loss, reduces the burden on their digestion, and takes care of their joints and organs. The next section details the most important nutrients for this stage.
Key Nutrients for the Senior Stage
To support the health of older pets, the diet should emphasize certain nutrients:
High-Quality Proteins: These are essential for maintaining and repairing tissues, especially muscle mass, which tends to decrease with age. Lean animal protein sources (beef, chicken, turkey, fish) that provide essential amino acids are recommended (11). Being highly digestible, these proteins favor the maintenance of strong muscles in seniors.
Omega-3 Fatty Acids (EPA and DHA): These essential oils (found in fatty fish like salmon, sardines, or in fish oil/flaxseed supplements) have powerful anti-inflammatory properties (12). They help relieve joint pain and protect brain health. They also promote a healthy coat and combat cellular aging.
Dietary Fiber: This helps regulate intestinal transit and prevent constipation, a common problem in older pets. A diet with a little more fiber (e.g., pumpkin, carrots, peas, or whole grains) improves digestion (13). Additionally, fiber provides satiety without excess calories, helping with weight control.
Antioxidants (vitamins A, C, E, other phytochemicals): These combat the free radicals generated by cellular aging and strengthen the weakened immune system. They are found in fresh fruits and vegetables (blueberries, carrots, spinach, broccoli, etc.) (14). A diet rich in antioxidants can slow the onset of chronic diseases.
Glucosamine and Chondroitin: While not essential nutrients in the strict sense, they are often added as natural supplements or are present in ingredients like bone broth. These substances support joint and cartilage health, relieving the osteoarthritic stiffness that appears with age (15).
Vitamins and Minerals: The absorption of micronutrients (calcium, phosphorus, B-vitamins, etc.) can decrease in old age. It is important to ensure an adequate intake. Balanced calcium and phosphorus care for bone health, and B-complex vitamins (B12, folic acid) are crucial for the nervous system (16).
Water: This is the most important "nutrient." Older dogs and cats lose some of their sense of thirst and are at risk of dehydration (17). They should always have fresh water available. Offering them wet food (which contains 70–80% water) can increase passive water intake (17) and is especially useful in dry climates or when the animal is not eating much.
Adapting Portions, Frequency, and Type of Food
Adjusting the feeding method is as important as the food's content. Some practical recommendations:
Small, frequent portions: In old age, digestion slows down. Instead of two large meals, offer several smaller portions per day (e.g., 3–4 meals) (18). This facilitates digestion and prevents stomach upset.
Wet food: Introducing canned or wet food (pâté) helps with hydration (17, 19). These foods are often softer and more palatable, ideal for pets with dental problems or a low appetite. The high water content also contributes to overall hydration.
Calorie control: It's easy for a sedentary senior to gain weight. Always follow the recommended portion guidelines for their ideal weight, adapting them to their activity level (20). Avoid excess: a pet should maintain its body condition within an optimal range. Weighing your pet periodically helps detect overweight or muscle loss.
Physical adjustments: For dogs with arthritis or reduced mobility, an elevated feeder (at chest level) can make eating more comfortable (21). For cats with osteoarthritis in their hind legs, placing the dish at a medium height or on a non-slip mat helps. Also, offer the dishes in a quiet, stable place (where no other animals compete for food) (22).
Dry vs. Wet: There's no single formula; a combination is often ideal. Dry food (kibble) is practical and helps with dental health by requiring chewing. Wet food provides hydration and palatability. For cats, it is especially recommended to use more wet food due to their tendency to drink little water. For dogs, choosing a mix of dry and wet food according to preference is also valid, while monitoring the total calorie count.
Monitor responses: Observe how your pet reacts to changes: if you notice stomach heaviness, vomiting, diarrhea, or a lack of food acceptance, adjust the portions, mix, or food types accordingly. If in doubt, consult a vet or animal nutritionist.
Commercial Foods vs. Supervised Homemade Diets
Quality commercial foods: These offer the easiest way to ensure balanced nutrition. The market has specific formulas for seniors with the right nutritional profile (high protein, controlled fats, added fiber, omega-3, and vitamins) (23). These kibbles and pâtés have been tested to meet the health needs of senior pets. For example, wet foods are often more energy-dense and easier to digest (24), which is useful for animals with low appetite or sensitive digestion.
Supervised homemade diets: It is also possible to prepare homemade meals, but always under professional supervision. A correct menu can include: cooked lean meats (chicken, turkey, beef, fish), cooked rice or oatmeal, and vegetables like carrots, pumpkin, or zucchini (25). These natural recipes provide fresh, nutritious ingredients. However, it is essential to supplement with vitamins/minerals (e.g., calcium, fish oil) to balance the diet. Furthermore, some popular homemade foods can be dangerous: never give chocolate, grapes/raisins, onions, garlic, avocado, among others (26). Always consult with a veterinarian to adjust the proportions and ensure the homemade diet has no deficiencies or excesses.
Warning Signs That the Diet Is Not Working
Even a well-planned diet can fail if the animal doesn't tolerate it or if it is insufficient. You should watch for any signs of deterioration. For example, a dull or poor-condition coat often indicates a lack of quality fatty acids or proteins (27). Persistent skin problems (irritation, itching) can also point to nutritional deficiencies. Persistent digestive disorders—soft, smelly stools, frequent vomiting, or gas—are clear signs that the food is not being assimilated well (28).
Other indicators include apathy or lack of energy, as well as drastic changes in appetite (e.g., continuous hunger or a total refusal to eat) (29). In these situations, re-evaluate the diet: it may be necessary to adjust the quantity, quality, or type of food. Any unexplained weight loss or gain should be a reason for a consultation, as it suggests the diet needs to be corrected. In general, a well-fed senior animal will maintain a lustrous coat, a good energy level for its age, and stable bowel habits (27, 30).
Gradual Transition to the New Feeding Plan
To avoid digestive problems, diet changes must be gradual. It is recommended to make the transition over a period of 7–10 days (31). For example, during the first 2 days, mix 25% new food with 75% of the old; then in the second step, 50%/50%; and finally, 75% new with 25% old until the change is complete. This allows the digestive system to adapt progressively. During this period, observe the animal carefully: if diarrhea, vomiting, or a lack of appetite appears, extend the transition for more days by reducing the proportion of the new food. Always offer fresh and clean food, and make sure the animal has permanent access to clean water. A well-planned and supervised diet change will minimize digestive stress and help your senior dog or cat get the most out of their new nutrients.
Sources: The information comes from veterinary guides and animal nutrition experts who describe the physiological changes of aging and recommend specific dietary adaptations for older dogs and cats (1, 6, 11, 18, 23, 27), among other specialized studies. These contributions support the practical recommendations presented here.
(1, 8) ¿Cuándo se considera a un perro sénior? | Purina
(2) ¿Cuándo y cómo cambiar el alimento para adultos por el alimento para perros senior? | Edgard & Cooper Base de conocimientos
(3) Gatos en edad adulta: Lo que necesitas saber para cuidar de un gato de edad avanzada | Purina
https://www.purina.com/es/articulos/gato/gato-senior/salud/edad-de-los-gatos-senior
(4) ¿Cuándo y cómo cambiar el alimento para adultos por el alimento para gatos senior? | Edgard & Cooper Base de conocimientos
(5, 6, 9, 10, 17) Envejecimiento y nutrición en nuestras mascotas | AniCura España
(7, 11, 12, 13, 14, 15, 16) Dieta natural para perros y gatos senior. ¡Descubre cómo cuidarlos!
(18, 19, 20, 21, 22) Alimentar a perros senior: la guía completa | Purina
https://www.purina.es/cuidados/perros/mayores/alimentacion/alimentar-a-perros-senior
(23, 24, 25, 26, 30, 31) Dieta equilibrada para perros | Santévet
https://www.santevet.es/articulo/como-alimentar-a-mi-perro
(27, 28, 29) Mi perro no come bien | Consejos ofrecidos por Chuchupets
AgroPetEd
Information about animals and agricultural practices
© 2025. All rights reserved.