An older dog is not just an adult dog with grey hair. Digestion changes, muscle is harder to keep, kidneys and joints need more care, and the amount of food that was right at five years old is often too much at ten. This senior dog diet guide covers what to feed a senior dog, how much, how often, and what to watch for — including when a change of diet is a vet decision rather than a shopping decision. It applies to dogs from about 7 to 8 years old for large breeds and about 10 to 11 for small breeds, the ages at which most dogs are usually considered seniors.
The first principle is that there is no single senior diet. A healthy, lean senior with good teeth needs something different from a senior with kidney disease, a sore mouth, or a weight problem. The guidance below is for a healthy senior; if your dog has a health condition, your vet should set the diet, and a therapeutic diet is a medicine in food form, not a brand choice.
How a senior dog's needs change
The biggest change is energy: most senior dogs move less, so they need fewer calories — typically the RER multiplied by about 1.2 to 1.4, against 1.6 for a typical neutered adult. For a 25 kg senior dog, the RER is about 70 × 25^0.75 ≈ 784 calories, so daily needs are about 940 to 1,100 calories, against about 1,255 for the same dog as a younger adult. That is a reduction of roughly a fifth to a quarter, and it is why so many senior dogs gain weight when their food stays the same: the dog slows down, the bowl does not, and the extra weight arrives quietly, a few hundred grams at a time.
Protein is the exception to the cutback. Older dogs need good-quality protein to hold muscle, and too little protein in a senior diet can speed up muscle loss. The old idea that senior dogs should eat low-protein food has been overturned: unless a vet has diagnosed kidney disease or another condition that requires protein restriction, a senior dog should eat a food with good, digestible protein. Fat should be moderate, fibre can help a senior that is prone to constipation or that needs to feel full on fewer calories, and water matters more than ever — older dogs can be less inclined to drink, and good hydration supports kidney health.
Teeth and digestion change too. Gum disease is common in senior dogs, and a sore mouth can make a dog eat less or drop food — if your senior dog suddenly eats less, check the mouth before changing the food. Digestion can become less efficient, so a highly digestible food, fed in smaller, more frequent meals, often suits a senior better than one large meal. And appetite itself can change in either direction: some seniors eat less and lose weight, which needs investigation, while others eat the same and gain weight, which needs a smaller ration.
What to feed a senior dog
A food labelled complete and balanced for seniors, or an adult food fed in a smaller amount with your vet's agreement, is usually right for a healthy senior. A senior food is typically a little lower in calories, with good protein, added fibre, and sometimes joint-support ingredients such as omega-3 fatty acids. The joint ingredients are a bonus, not a treatment: if your dog has arthritis, your vet should manage it, and food alone will not fix it.
Wet food can help a senior that drinks little or that has a sore mouth, because it adds water and is easier to chew — but it is also easier to overfeed, because a tin looks small while containing as many calories as a bowl of dry food. Mixed feeding is fine as long as the total calories add up. Home-cooked food is possible, but a homemade senior diet needs a recipe from a veterinary nutritionist, because an unbalanced home-cooked diet can cause deficiencies that show up slowly in an older dog. Treats should stay under 10% of daily calories, and soft treats are kinder to old teeth than hard biscuits.
Supplements are widely sold for senior dogs, and the evidence for most of them is thin. Omega-3 fatty acids from fish oil have the best support, for joints and coat, but the dose should be agreed with your vet, especially if the dog takes other medicines. Do not buy a supplement to treat a diagnosed condition without veterinary advice — and do not delay a vet visit because a supplement seems to help.
How much and how often
Feed a senior dog twice a day, and consider three smaller meals if the dog has a sensitive stomach or tends to be sick on an empty stomach. Measure food with scales, weigh the dog monthly, and adjust by body condition: you should be able to feel the ribs easily and see a waist from above. If weight drifts up, cut food by about 10% and re-weigh in a month; if weight drifts down without explanation, see a vet before cutting or increasing food, because weight loss in a senior dog is often the first sign of an underlying problem.
A practical starting point for a healthy senior is the RER × 1.2 to 1.4. For a 10 kg senior dog, the RER is about 394 calories, so daily needs are about 470 to 550 calories. For a 25 kg senior, about 940 to 1,100 calories. For a 40 kg senior, about 1,330 to 1,550 calories. Those are starting points — a senior that still runs every day needs more, and one that mostly sleeps needs less. The dog calorie calculator works it out from your dog's weight, age, and activity, and the dog food calculator converts it into cups and grams.
When a diet change is a vet decision
Some senior dogs need a therapeutic diet, and those are vet decisions. Kidney disease usually means a diet lower in phosphorus and with controlled, high-quality protein. Heart disease can mean a diet lower in sodium. Dogs with chronic digestive problems may need a highly digestible or hydrolysed diet. Dogs that are losing weight for no clear reason need investigation before any diet change. In all of these cases, the diet is part of the treatment, and changing it without veterinary guidance can make the condition worse.
Watch for the signs that should trigger a vet visit rather than a food change: drinking much more than usual, urinating more, weight loss, vomiting or diarrhoea that lasts more than a day, a swollen belly, or a sudden change in appetite in either direction. Mention these promptly — senior dogs can deteriorate quickly, and early help works better than late help. And keep dental care going: a senior dog with a sore mouth will eat less, lose weight, and be miserable, and dental treatment in an older dog is routine for a vet, even though it needs an anaesthetic.
A sample senior feeding day
A 25 kg senior dog needing about 1,000 calories a day might eat two meals of about 140 g of a typical dry senior food (around 350 kcal per 100 g), or one meal of dry food and one of wet food adding up to the same total, with a few small soft treats during the day. Water should always be available, and the bowl should be easy to reach — a raised bowl can help a stiff senior that finds bending down uncomfortable. Feed at the same times every day, keep the routine calm, and weigh the dog monthly so slow changes do not creep up unnoticed.
For related reading, see the dog calorie calculator, the dog food calculator, the senior dog age calculator, the Labrador Retriever food guide, the overweight dog signs guide, the dog breeds hub.
Frequently asked questions
How much should I feed my senior dog?
Start with the RER × 1.2 to 1.4 — about 940 to 1,100 calories a day for a 25 kg senior dog — then adjust by body condition and your vet's advice. Senior dogs usually need about a fifth to a quarter fewer calories than they did as younger adults.
Should a senior dog eat less protein?
No, unless a vet has diagnosed a condition such as kidney disease that requires protein restriction. Healthy seniors need good-quality protein to hold muscle, and too little protein can speed up muscle loss.
Is senior dog food necessary?
Not always. A complete adult food fed in a smaller amount can be fine for a healthy senior, but a senior food is usually a little lower in calories with good protein and added fibre, which suits many older dogs. Your vet can advise for your individual dog.
How often should I feed a senior dog?
Twice a day, or three smaller meals if the dog has a sensitive stomach. Measure food with scales and weigh the dog monthly.
Why is my senior dog losing weight?
Weight loss in a senior dog should always be checked by a vet before changing food — it is often the first sign of kidney disease, dental problems, thyroid disease, or another underlying condition. Do not simply feed more until the cause is known.
What treats are best for a senior dog?
Small, soft treats that are easy on old teeth, kept under 10% of daily calories. Avoid hard biscuits for a dog with dental problems, and count treats in the daily total.
Results on this page are estimates for general information only and are not veterinary advice. If your pet is ill, underweight, overweight, pregnant, or has a health condition, consult your veterinarian before changing diet or care.