Medically Reviewed Evidence Based

When Should I Change My Dog’s Food?

Written by: Kristina Lalovic
Margarita Boyd
Reviewed by: Dr. Margarita Boyd, BVSc MRCVS
Is feeding dogs the same food wrong or good? When should you switch from puppy to adult food? In this article, we will cover these and many other questions.

Some people might think they only need to choose one good pet food for their beloved dog and then feed that same food for the rest of their dog’s life. However, that is not the right approach at all… imagine eating the same meal for your entire life?!

There are lots of different reasons why you might need to change your dog’s food.

  • Firstly, your dog’s nutritional requirements will change over time, examples include from puppy to adult, and also if his activity level changes too.
  • Secondly, you might need to change your dog’s food for health reasons, if he is showing signs of a food allergy, decreased energy levels, hyperactivity or poor coat, and skin health.

In this article, we will discuss when you should change your dog’s food in the different life stages and common signs that your dog needs a new diet.

We will also look at the safest way to change foods (Yes, there is a safe way!), and also when you might need to seek veterinary advice.

Canine Diet

Let’s take a quick look at your dog’s nutritional needs.

The teeth and intestinal tract of dogs have become adapted to eat an omnivorous diet. Omnivores eat a combination of meat and plant foods to meet their nutritional requirements.

It is quite a debatable topic but dogs seem to be omnivores but with a “carnivorous bias”, meaning they need extra meat in their diet! (1).

To stay healthy dogs need a well-balanced diet. This means it must contain the correct balance of minerals, vitamins, essential amino acids (from proteins) and essential fatty acids (from fats).

These components are needed for the dog’s body to carry out all its essential functions, build and maintain tissue and produce energy.

If the diet is lacking in some of these components your dog can quickly become dull and sick!

Wondering how to evaluate a dog’s food quality?

We’ve already done that for you, so please check the section where we compared the most popular dog foods.

Different Life Stages = Different Food

During different stages of your dog’s life, he will have different dietary needs.

There is no one food that can achieve everything your dog needs for his entire life- it just doesn’t exist- no matter what the advertising on the packet says!

For example, a growing puppy needs much more energy and nutrients than a senior dog.

And if an adult dog is fed a puppy formulated diet, it will likely pile on the pounds quite quickly and become fat.

Veterinary nutritionists now recommend that you should feed your dog according to his life stage to keep your dog healthy and improve his quality of life.

So, what are the different life stages?

At What Age Should I Change My Dog’s Food?

There are three main life stages which expert nutritionists say are important in your dog’s life: Puppy, Adult, and Senior (2).


Puppies are very active and like to eat, needing to be fed often due to their relatively small stomachs.

They are growing and developing rapidly, therefore they need a specially formulated puppy diet to meet their high nutritional demands, especially high in energy and calcium.

Most puppies will start to be interested in solid food at 3-4 weeks before this their mum’s milk will provide all their nutritional needs.

They are usually weaned off their mum’s milk at 6-8 weeks.

Feeding your puppy an adult dog diet could result in stunted growth, an imbalance of calcium, and health problems in later life!

If you have a large or giant breed puppy, then you need to be extra careful with their diet as they grow.

These larger breed dogs (e.g. Labrador, Golden Retriever, German Shepherd, Great Dane) have been shown to be at a higher risk of developing hip and elbow dysplasia and other joint abnormalities if fed a diet with excess energy, calcium and vitamin D (3).

These puppies should be fed a diet formulated for large breed puppies, which helps to prevent excessive fast growth, allowing the joints to develop slowly and hopefully preventing joint problems when they are older.


The transition time from puppy to adult food depends on the breed of the dog.

For many breeds, their growth is almost complete between 8-10 months of age, but for giant breeds, they may not be physically mature until 18 months old.

The average puppy can be switched to adult dog food at around 12 months of age, but ask your veterinarian for advice regarding your breed of dog.

A maintenance adult dog food will have lower calorie content, reduced fat, and nutrients when compared to a puppy diet.


Although it is debatable at what age a dog becomes senior, a general rule is over seven years of age.

Older dogs may be less active and therefore benefit from a reduced calorie diet to prevent obesity, with higher protein to maintain their muscle health.

Often senior diets have additional omega-3 fatty acids and antioxidants to support aging, combat inflammation, and promote healthy skin and coat.

It might also have added nutrients such as glucosamine to promote joint health, especially as arthritis is a common problem in aging dogs.

Pregnant Mothers

Pregnancy and lactation (nursing) are additional times when a dog’s diet needs to be changed to meet her nutritional requirements.

These times put a big strain on the mummy dog’s body and she needs good quality, nutritious food to stay healthy and produce healthy puppies.

Now that we have covered different life stages, let’s take a look at why and when you might need to change your adult dogs’ diet.

Is it Good to Change My Dog’s Food?

It actually is a good idea to periodically change your dog’s food. We don’t mean every day, and it may only be small changes, but there may be some benefits:

  • May help prevent food allergies
  • Provides a variety and change of essential nutrients
  • Offers your dog variety of flavor
  • May make your dog less “fussy”

Offering your dog a diet with only chicken or only beef for the rest of his life, sounds pretty boring, right?!

All mammals, like dogs, have evolved to eat a range of different foods in order to get all their necessary nutrients, vitamins, and minerals.

Changing your dog’s food, or offering some variety every so often, means that your dog will be receiving a varied diet like they were designed to eat.

Many veterinary nutritionists now advise feeding your dog a variation of different foods from a young age, to help avoid the development of food allergies. This is often the advice given to humans too!

Changing the source of protein (e.g. chicken, lamb, fish, beef) in your dog’s diet every so often could help reduce the likelihood of your dog developing allergies or food intolerances.

Did you know that dogs often develop an allergy to a food (and often a protein source) that they have been eating for YEARS? (4)

Therefore, it is actually a good idea to rotate your dog’s food every 3 months or so, changing the main protein source in the diet.

You can also add in some healthy vegetables a couple of times a week, to give your dog’s diet a change in flavor and texture. Examples include some cooked sliced carrots, broccoli, or sweet potato.

Not all vegetables are safe for dogs to eat, check out this useful list of foods to avoid feeding your dog.

How to Change Foods Safely?

It is advised not to change to a totally new diet too quickly, as that could cause your dog to have an upset stomach, with diarrhea or excess gas. Some dogs are more sensitive than others when they have changes to their diet.

Switching foods should take about a week, where you slowly mix a little bit of the new diet with the old diet, increasing the portion of the new diet every day.

This gives your dogs gastrointestinal tract (specifically the normal bacteria which live in the intestines) time to adjust to any changes in the food and allows you to check for any signs of an upset tummy.

Watch this video and make sure you transition your dog’s nutrition to a new food safely.

Signs that You Need to Change Your Dog’s Food

If your dog is eating a good quality, nutritious diet, then he is more likely to feel great and look healthy on the outside too.

There are some obvious signs that your dog might show that can be linked to a poor diet. If your dog is showing any of these signs, it may be time to change your dog’s food!

Here are six common signs that your dog needs a new diet…

1. Dull Coat & Flaky Skin

If a dog’s diet has an imbalance in vitamins and minerals or is lacking in essential fatty acids, then this often causes the coat to be dull and dry and the skin to be flaky.

Choose a diet enriched with vitamin B, omega-3 and omega-6 fatty acids to get his skin and coat beautiful again(5).

2. Gastrointestinal Upset

Many owners have dogs which show signs of excess gas or frequent, loose stools and think that is normal for their dog.

It is not normal and is probably caused by food intolerance or feeding poor-quality dog food.

Talk to your veterinarian about switching to a better quality diet, or a specialized sensitivity/digestive health diet.

3. Hyperactivity

Is your dog always hyperactive? We know that some breeds are much more active than others, and it is normal for puppies and young dogs to often have boundless energy levels BUT some dogs show signs of hyperactivity and agitation. This could be linked to his diet!

Lots of commercial dog foods (even some well-known brands) contain lots of chemicals, preservatives, food colorings, artificial, and even unspecified protein sources.

Check the ingredient list on your dog food today, and if in doubt choose a better quality, natural-based dog diet instead, free from all the nasty extra additions.

4. Overweight

Pet obesity is an increasingly common problem, with a recorded worldwide prevalence of up to 44% (6).

It might be because your dog isn’t receiving enough exercise, or because you are feeding your dog a diet that isn’t right for his life stage.

For example, giving an adult dog a puppy diet will often cause him to quickly pile on the pounds, or maybe your dog just gets too many treats or human food?

The best way to get your dog to lose the extra weight is to start regular exercise (as advised by your vet) and choose a specialized weight loss diet.

Those diets are still jam-packed with the necessary nutrients, vitamins, and minerals but have fewer calories, and take advantage of the latest research to keep your dog feeling “full” so he doesn’t beg for more.

5. Itchiness

If your dog is itching all the time, and parasites (e.g. fleas, mites, ticks) have been ruled out, then it could be allergies.

Constant itching is very uncomfortable for your pet and frustrating for the helpless owner who has to watch it. Allergies are actually quite common in pets, and food is one of the possible causes(7).

Many allergic pets benefit from switching to a low allergen or hypoallergenic diet, which reduces the number of potential allergens the intestinal tract has to deal with(8).

6. Dull and Lethargic: recovery from illness

If your dog is recovering from a recent illness, surgery or a stressful event, he may be feeling a little run down and duller than normal. Can his normal diet support him through times of illness or recovery?

In these times, he might benefit from a diet that has a high energy content and is enriched with immune-boosting antioxidants, to boost his recovery.

However, if your dog is suddenly acting dull, weak or lethargic then it is important to seek veterinary advice before changing his diet.

When to Seek Advice

It is always a good idea to seek advice from your veterinarian or a veterinary nutritionist if you need advice about your dog’s diet or if your dog seems ill.

If you think your dog could benefit from a change in food, but you aren’t sure which one is best then ask for advice.

You could spend a small fortune and waste a lot of time buying lots of different dog foods while trying to figure it out by yourself.

This is especially important if you want to prepare your dog’s food at home from scratch. It can be difficult to get the right balance of vitamins, minerals, proteins, fats, and fiber that your dog needs to stay healthy.

Feeding a diet with too much of one mineral, or too few vitamins could result in serious health problems for your dog.


Choosing the right diet for your dog is not always easy, as there are literally hundreds of brands and formulas available.

You don’t need to buy the most expensive one, but choose a high-quality diet instead of the cheapest one on offer.

Remember to choose a diet that is right for your dog’s life stage (puppy, adult or senior) and that isn’t full of artificial colors, preservatives, and flavors.

Talk to your veterinarian if you need help choosing a specially formulated diet for your pet’s individual needs. A good quality, nutritious diet can help your dog live a long happy life!

Frequently Asked Questions On When You Should Change Your Dog’s Food

1. Are You Supposed To Switch Your Dogs Food?

Simply said, yes. Once you get a dog your veterinarian should inform you to be careful when it comes to the dog’s diet.

In other words, you should get concrete advice on how to follow the dog’s development and adjust his diet to a new life stage.

For better results, you should also think about the flavor and do your best to provide food that is of high quality, protein-based, and various in flavor.

2. Do Dogs Get Bored Of Eating The Same Food?

Dogs have different taste receptors than humans do, so we cannot say that they get bored of identical food unless they show us.

If tired of the identical taste, your dog will start refusing food and that is usually the first sign that you should incorporate rew flavors into Fido’s diet.

3. How Often Do Dogs Get Bored Of Their Food?

You don’t have to change the dog’s food every week. If you believe that your dog is hungry for new flavors, you can just upgrade his existing meal.

This means that you can add a tablespoon of olive oil to canned or dry food, add some fresh carrots, or pour over a glass of yogurt. Adding an egg also does wonders for dogs’ appetites.

4. Can Changing Dog Food Cause Blood In Stool?

In general, this should not be the case. If it happens it means that your dog’s stomach is highly upset and that there is an underlying medical issue.

Make sure that you contact your veterinarian. Bloody diarrhea is something that you never want to see in your dog.