Senior Dog Food: What to Compare
What changes in an older dog's diet according to the Merck Veterinary Manual - possibly more protein, weight that can go either way - why there is no official senior nutrient standard, what a 2025 study of 61 adult and senior foods found, and three senior dog foods compared on what their makers publish.
AI illustration This is a reading guide to published veterinary information and to what makers state on their own pages. An older dog that loses or gains weight, drinks more or eats less needs a vet check before a change of food: kidney, liver and hormone problems are common at this age, and some need a prescription diet.
The short answer: “senior” on a bag is the maker’s own label, not a standard. In the United States, the AAFCO and NRC nutrient profiles cover growth, reproduction and adult maintenance. The Merck Veterinary Manual notes that neither recognizes that requirements may change in healthy older dogs. So choose by your dog’s weight, body condition and health, with your vet, and use the label to check what you are buying.
What Changes With Age
From Merck’s professional guidance on feeding older dogs (Merck):
- Protein. Older dogs may not use dietary protein as efficiently as younger dogs, so they may need more of it than younger dogs to keep their protein reserves.
- Weight goes both ways. Some dogs start old age considerably overweight, while others lose condition. A food with more or less energy, fat or fiber may be needed to keep a healthy weight.
- Check-ups. Merck advises a preventive health program with regular checks of body weight and condition, organ function and, in dogs, cognitive function.
For comparison, Merck gives the AAFCO minimum for adult dogs as 18% protein on a dry-matter basis.
What a 2025 Study of Senior Foods Found
Researchers at Colorado State University analyzed the nutrient content of 61 adult and senior dog foods (German et al., 2025). They found that senior diets varied widely and did not consistently differ from the same makers’ adult foods. Fiber, fat and energy density varied most, especially in canned foods. 11 of the 61 products, 18%, did not meet at least one AAFCO adult maintenance requirement. The authors link the variation to the lack of a defined nutrient profile for senior dogs, and call their study exploratory. In practice, two “senior” foods can be very different, so read the label of each.
Three Senior Dog Foods Compared
| Food | For | First ingredient | Protein | Energy | AAFCO statement | Links |
|---|---|---|---|---|---|---|
| Hill’s Science Diet Adult 7+ Senior Vitality, Chicken Recipe | Dogs 7 and older | Chicken | Hill’s gives dry matter: 22.1% (fat 14.2%) | 359 kcal per cup | Feeding tests, adult maintenance | See on Amazon · Maker’s page |
| Hill’s Science Diet Adult 11+ Small & Mini, Chicken, Brown Rice & Barley | Dogs 11 and older, up to 25 lb | Chicken | Hill’s gives dry matter: 22.5% (fat 17.9%) | 378 kcal per cup | Feeding tests, adult maintenance | See on Amazon · Maker’s page |
| Royal Canin Size Health Nutrition Large Adult 5+ | Large dogs 56-100 lb, over 5 years | Chicken by-product meal | 24.0% min, as sold (moisture 10% max): about 27% dry matter | 337 kcal per cup | Formulated to meet, adult maintenance | See on Amazon · Maker’s page |
How we put this together. Three senior foods from two makers, covering small and large dogs, compared on what each maker states on its own product page, checked on 26 October 2026. All three carry an AAFCO statement for adult maintenance, and their age labels (5+, 7+, 11+) are the makers’ own. Hill’s gives its nutrients on a dry-matter basis. For Royal Canin, the dry-matter figure is our rough arithmetic: minimum protein divided by the share that isn’t water. We have not fed these foods. None of them is a diet for kidney, liver or heart disease; those come from your vet. There are no prices here: the Amazon links search for the exact food, and we may earn a commission if you buy through them.
Day to Day
- Keep the ribs feelable. For most breeds, Merck says you should be able to feel the spine and ribs but not see them (Merck).
- Table scraps: never more than 10% of daily calories, Merck says.
- Water: always available, unless your vet advises otherwise.
- Change food gradually and watch weight over the following weeks.
