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Should I Change My Dog’s Food? 

Written by Ella White


Spaniel sitting next to bowl of dinner

Once you’ve got your dog settled with their diet, it can seem unnecessary to ever change the food you feed them. Especially if they’re a fussy eater and it’s taken a while to find something they’re happy with. But as your dog gets older, their dietary needs are likely to change. Whether due to old age, illness, or other factors, there are different reasons that you might have to change your dog’s food at some point in their life.

But whether your vet has recommended a new diet, your dog’s lifestyle means they need something different from their food, or you just think it’s time for a change, making the switch isn’t simple. How do you change your dog’s food? What is the best dog food to choose? And what happens if the transition upsets your dog’s stomach?

In this article, we’ll break down whether you need to change your dog’s food, and how to do it.

Do I Need To Change My Dog’s Food?

What your dog eats is as important as exercise and mental stimulation when it comes to making sure they lead a long and healthy life. But age, medical reasons, and how much they exercise can all influence a need for change in their diet. So, if you think it might be time for something new, always speak to your vet before you make the switch. After all, changing your dog’s diet is not a task to be taken lightly.

On the other hand, you might not even have considered that your dog might be happier or healthier with a different food. These are some of the most common reasons that your vet might suggest a change in your dog’s diet.


Just like many humans are allergic to certain foods, dogs can be too/learn/dog-health/your-simple-guide-to-allergies-in-dogs. And while many dog foods are allergen-free for this reason, there are still plenty that include ingredients like corn, wheat, and soy. Some dogs are also allergic to ingredients that are less common allergens, like certain meats and vegetables. So if you notice that your dog is itching or has sensitive skin, it could be something in their diet that’s the cause. Dogs can develop allergies or intolerances just as quickly as humans can. So don’t assume that just because they happily gobbled down a certain ingredient when they were younger, they haven’t developed an allergy over time. 

Old Age

Your dog’s dietary needs will change with age/learn/dog-health/how-to-keep-your-older-dog-healthy – not just in terms of how much they eat, but also the ingredients they benefit from. Puppies and young adult dogs have a lot of energy so they need a higher calorie diet. 

But as they get older and more sedate, they require fewer calories but extra supplements. For example, older dogs often need more dietary fiber, less fat, and supplements that can help their joints/products/the-one which get stiffer with age.

Weight Gain

If your dog has started to gain weight, they might need a diet overhaul. Rather than just cutting their portion size, it’s important to ensure that overweight dogs/learn/dog-health/how-to-help-my-dog-lose-weight-diet-and-exercise-for are getting all the nutrients they need… just in the form of fewer calories. So your vet might put your dog on a specific, calorie-controlled diet to help them lose weight healthily.

Stomach Issues

Some dogs can’t tolerate certain foods. So if you notice that they’re especially gassy, are suffering with diarrhea/learn/dog-food/my-dog-has-diarrhea-will-oatmeal-help or vomiting, or their gastrointestinal functions just aren’t quite right, it could be because of what they’re eating. This isn’t just painful and upsetting for your dog, but it’s probably not great for you as their owner either. To confirm the cause of your dog’s upset stomach, always consult your vet and don’t make any changes to their diet without professional advice.

Energy Levels

Whether your dog is weakened from surgery, getting older, or is lethargic for other reasons, then their dietary needs are likely to change. Dogs that are expending less energy may need fewer calories. And if you’re trying to boost their energy levels or help them recover from an illness that’s impacted their appetite, foods that are rich in antioxidants can help them get better faster. However, don’t change your dog’s diet – particularly in terms of calorie intake – without consulting your vet first.

Lacking nutrients

There are certain ways that you can tell your dog isn’t getting the right nutrients, or the right quantities of the nutrients they need. A dull coat/learn/dog-health/how-to-make-my-dogs-coat-shiny, flaky skin/learn/dog-training/how-to-keep-your-dogs-coat-healthy, cloudy eyes, and lethargy are just some of the tell-tale signs. Speak to your vet to discover which nutrients they’re lacking, and plan an improved diet for your dog/learn/dog-food/healthy-things-to-add-to-dog-food. They might just need a boost in fatty acids to get their coat and skin back to scratch. Or they could need bigger changes to help improve their overall health.

Change in the market

Thankfully the pet food market has seen a huge change in the last few years. The more we understand about our dogs' digestive and immune system, the more we can adapt what we’re feeding them. It’s not uncommon to feed our dogs the same brand we’ve always used or even the same food our parents fed the family dog growing up. And whilst the argument that they managed to survive for hundreds of years hunting and foraging for scraps, the fact of the matter is, a dog on a healthy, well balanced diet will be more likely to enjoy a happier, healthier, longer life. 

Issues With Changing Your Dog’s Food

Even if you’ve changed your dog’s diet to help address specific medical needs or health concerns, there’s still a chance they won’t take well to their new food. Adapting to an entirely new diet is tougher on your dog’s digestive system than simply adding a supplement or making slight adjustments to their normal food intake. So be patient, and understand the signs that might indicate something more serious is up.

Gastrointestinal issues like vomiting, diarrhea, and increased appetite or food refusal could be a sign that your dog’s new diet doesn’t suit them. While cutaneous side effects like hair loss, rashes, itching, and inflammation could be a sign of an allergy or other adverse reaction to their new food.

Always work with your vet to diagnose the cause of any illness or adverse reaction your dog might be suffering. And never change their diet or medication without speaking to a professional for advice. They might suggest an elimination trial to help single out the foods that are causing issues for your dog. Or they might diagnose a different cause altogether.

If you think your dog’s diet is causing them problems, keep an eye on their poop/learn/dog-health/dog-poop-everything-you-need-to-know. The frequency and consistency of their toilet habits will be one of the best ways for vets to understand what’s up.

How to Change Your Dog’s Diet

If you’re ready to change your dog’s diet and your vet feels confident that this is the right course of action, then it’s not as simple as just giving them a different food for dinner that night. Abrupt changes to what your dog eats can cause stomach issues like diarrhea and vomiting – even if they have not previously suffered from these ailments.

Dogs don’t have the same number of taste buds we have. Whilst we might get bored eating the same meal every day, your dog does not so don’t assume they’re simply craving a change. 

The best way to switch your dog’s diet without causing any disruption to their gastrointestinal function is to slowly transition their food over seven days..

  • Days 1-2: Serve your dog 1 part new food and 3 parts old food, on two separate bowls to get them used to the smell of their new diet
  • Days 3-4: Serve 2 parts new food, 2 parts old food, combining them in the same bowl
  • Days 5-6: Serve 3 parts new food and 1 part old food in the same bowl
  • Day 7: 100% new food.

If you know your dog has problems with their digestion, allergies, or a sensitive stomach then you may want to take this process even slower over two weeks. And if at any point your dog refuses the new food, you might need to decrease the quantities in which it’s introduced. Always feed your dog the right amount of food per day, even if it means feeding them more of the food you’re trying to phase out.

During this period, keep a close eye on your dog’s toilet habits and their behavior. If they display any changes, including an upset stomach, lethargy, or other signs of illness, consult your vet before continuing with the diet transition.

Picking The Best Food For Your Dog

Picking the right food for your dog can be a challenge. No two dogs are the same and their dietary needs are likely to be unique to their breed, size, age, activity levels, taste, and any health issues they might have. And while there is no one ‘best’ dog food, there are different factors to consider when choosing how you want to feel about your dog.

Firstly, carry out extensive research into the type of food you want your dog to eat. The internet – and even some dog food brands – can perpetuate myths about the healthiest ways to feed your dog. But this information isn’t always accurate.

You can learn more about how dog food is categorized and whether it’s really healthy for your dog by understanding dog food labels/learn/dog-food/the-95-rule-how-is-pet-food-named. There are strict rules in the USA about how dog food can be named. And it all depends on what goes into the food.


One of the cheapest and easiest ways to feed dogs is with kibble. Usually in the form of dried pellets or biscuits, kibble is a dry, processed dog food that lasts a long time, can be stored anywhere, and is easy to serve in just one scoop. But beyond its convenience, there are questions around whether kibble is actually the healthiest way to feed dogs. 

While some brands make dried dog food that is healthy and nutritional, some kibbles are cheap and low quality. And even worse, they can even contain hidden additives and nasties including spoiled foods, non-nutritional fillers, and even pesticides and heavy metal contaminants. There are many reasons why vets recommend against kibble/learn/dog-food/why-vets-recommend-air-dried-food-over-kibble-and-fresh-frozen. So if you’re opting for this as your dog’s diet, be sure to do plenty of research into the brands you buy from.


Many dog owners opt for fresh-frozen food as the ‘healthiest’ way to feed their dogs beyond home-cooking their meals. And while some fresh and frozen food can be good for pets, in many instances the basic ingredients themselves don’t hold all the nutrition that your dog needs. Which is why many fresh-frozen dog meals have been found to include hidden fillers.

Before you choose a fresh-frozen diet for your dog, make sure you research the different brands available. The more transparent they are with their ingredients, the more confident you can feel that your dog is being fed only the best meat and veg.

Frozen dog food can also take up a lot of room in your freezer, and each pack needs to be defrosted and then stored in the fridge ahead of time. This means that as well as taking up valuable kitchen space (and stinking out your fridge), frozen food requires more prep time than dried options.

That said, it is healthier than kibble in the sense that you can rest assured that the base recipe does include the meats and other fresh ingredients it says it does. 


Air-dried dog food is the best choice for your dog’s all round health and wellbeing. It combines the convenience of kibble with the nutrition and tastiness of fresh or frozen meals. Most reputable brands will be able to prove they’re approved by vets, and make sure they’re packed with all the vitamins, minerals, and nutrients your dog needs in a day. 

Look for a brand that never hides its ingredients so you can see that everything they’re eating is natural, pure, and fresh with no hidden nasties or additives.