Switching food, step by step

Dogs: about a week

• Days 1–2: ¼ new, ¾ old food.
• Days 3–4: half and half.
• Days 5–6: ¾ new, ¼ old food.
• From day 7: only the new food.

If your dog has a sensitive stomach, take more time.

Cats: often one to two weeks

Many cats won’t eat mixed food. Offer the new food in a separate bowl next to the old one.

Start with a teaspoon next to the usual meal, then a little more new and less old each day. After about two weeks, the old food can go.

Important for cats

If your cat won’t eat the new food, don’t force it and don’t let your cat go hungry. In cats, even 24 hours without food can be serious. Offer the old food again and talk to your vet.

Same calories, new amount

A new food often has different calories per cup or per kg. Work out the amount again, or you may feed more or less than before without noticing. The food calculator does it in a minute.

When to call the vet

• Vomiting or diarrhea doesn’t go away despite a slow switch.
• Your cat doesn’t eat for a day.
• Your pet eats a food prescribed by the vet or is ill: talk about the switch first.

How long exactly?

Sources don’t agree: from at least 3 days (WSAVA) to about 14 days for cats (PDSA). No single method is proven best. A week for dogs and one to two weeks for cats sit in the middle.