Last Updated: 29/09/2026
How to Introduce a New Food to Your Pet
Switching your pet's diet? Our vet guide explains how to transition them to a new food safely. Learn the 7-10 day plan to prevent tummy upsets and get tips for fussy eaters.
Author: Dr Teagan Lever BVSc (Hons)
Reading Time: 8 minutes - short read
Changing your pet's food is a task most pet parents will face at some point. There can be a number of reasons why you may need to do this. They may have graduated from puppyhood or kittenhood to adulthood - see our guide on when to change your pet's food for their life stage - perhaps they have developed a medical condition requiring special food; or maybe you want to upgrade from a supermarket brand to a premium diet with higher-quality ingredients and better digestibility.
Whatever the reason, it might seem like a simple swap. However, switching a pet's food too quickly is a very common cause of digestive upsets, like gas, vomiting, and diarrhoea.
The secret to success is a slow, gradual transition. To switch your pet safely to a new food, mix it in gradually with their current food over 7 to 10 days, increasing the new food's share each day until they're eating 100% new food by day 7. This slow transition gives their gut bacteria time to adjust, helping to prevent the vomiting, diarrhoea and gas that come from switching too fast.
Why do I need to transition my pet's food slowly?
Your pet's digestive tract is home to a massive community of bacteria and other microbes, often called "good bacteria." This microbiome is essential for healthy digestion. These microbes adapt to the specific ingredients and nutrient profile of your pet's current food. When you suddenly introduce a new food, this delicate balance is disrupted, which can lead to that familiar gastrointestinal (GI) upset.
A slow introduction gives the gut microbiome time to adjust, allowing the right bacteria to thrive on the new nutrients and ensuring a happy digestive system.
How do I transition my pet to a new food?
To save your pet from developing diarrhoea and flatulence, introduce the new food gradually over a period of one to two weeks. This means planning ahead and buying a bag of the new food before the old one runs out!
You may be lucky and have a pet with an iron gut, who won't show any signs of a tummy upset with a quick change of food. Your pet is also less likely to react if you are making benign change, such as swapping from a chicken-based dry food to a beef-based dry food of the same brand. However, most people prefer not to take the risk, as diarrhoea on the carpet is never fun to clean up!
Most sources you read will recommend a 'gradual' change, and when googling the topic, you might notice there are a wealth of different methods recommended by different sources. So long as the time period allowed is gradual, there's not really any wrong 'method' and you might find that a different method suits you and your pet. However, after thoroughly reading up on the topic, we have based our recommendation on that made by nutritionists from both Hill's and Royal Canin due to their heavy backing of research into animal nutrition science.
Here's what we recommend:
- Day 1-3: Mix 25% of the new food with 75% of the old food
- Day 4-6: Mix 50% of the new food with 50% of the old food
- Day 7-9: Mix 75% of the new food with 25% of the old food
- Day 10 onwards: 100% new food
Vet tip: Make sure to mix the new and old food together thoroughly. This can help to stop clever pets from just picking out their old, familiar favourites and leaving the new food in the bowl.
How do I get a fussy eater to accept new food?
It's not uncommon for picky eaters to turn their nose up at something they haven't encountered before.
Provided your pet is otherwise bright, well, and showing no signs of illness, the goal is to make the new mixed food more appealing. The best way to do this is by using their powerful sense of smell. Enhancing the food's aroma is often enough to convince them to take that first bite.
Vet-approved tricks to tempt a fussy eater:
- For dry food (kibble): Try mixing in a small amount of warm water or a pet-safe, low-sodium broth. This creates a bit of a gravy and helps to release the food's aroma, making it much more inviting.
- Use the microwave (with caution): You can heat either wet food or a kibble-and-water slurry in the microwave for a very short burst (around 5-10 seconds).
- Crucial safety warning: If you do warm the food, always stir it thoroughly to check for hot spots and test it with your finger. It must be lukewarm, never hot. Accidentally burning your pet's mouth is a sure-fire way to put them off the new food for good!
- Be patient and consistent: Don't give in immediately and offer their old food or human treats. Put the bowl of mixed food down for 15-20 minutes. If they walk away, calmly remove the bowl and try again at their next scheduled mealtime.
For more tips, read through our guides to Feeding Fussy Dogs and Feeding Fussy Cats.
What should I do if my pet refuses the new food?
Don't fret if your pet decides they would rather go hungry than eat their new food. For a healthy cat or dog, skipping a meal will not cause any harm. If you give in immediately your pet will quickly learn that they have you wrapped around their little finger and will keep on holding out for the good stuff! In most cases if you don't give in, it's likely that by the next mealtime they will be hungry enough to give the new food a go. If your pet refuses more than two meals in a row, you may need to consider offering an alternative diet.
A quick note for cat owners: unlike dogs, cats can develop a serious complication called hepatic lipidosis (fatty liver disease) if they go without food for more than 24-48 hours, especially if they're overweight. If your cat skips more than 1-2 full days of eating, don't wait it out - contact your vet.
FAQs
Changing your pet's food doesn't have to be stressful. By following a gradual 7-day transition, you give their digestive system time to adapt, preventing most tummy upsets. It’s normal for some pets to be fussy, but using tricks like warming the food can help. If your pet refuses to eat for more than two meals or develops persistent diarrhoea, it's always best to consult your veterinarian for advice.
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History
Our experts continually monitor the health and wellness space and we update our articles when new information becomes available.
Tue 29 Sep 2026
Edited by Dr Gillian Hill BVSc (Hons)Dr Teagan Lever BVSc (Hons)
Head Veterinarian, BVSc (Hons)
Pet Circle's Head Veterinarian, Dr Teagan graduated from the University of Queensland in 2010 and went on to work in small animal and mixed practice in various locations around QLD & ACT before joining Pet Circle in early 2016. Dr Teagan has special interests in dermatology, nutrition and preventative health care. She feels privileged to witness the special bond people share with their pets on a daily basis and enjoys forming lasting relationships with pet parents and their fur children.
