How Do I Change My Dog’s Food Safely?


You may find you need to switch your dog’s food at some point, so it’s imperative to learn how to do this safely and without triggering a stomach upset.

There are many reasons why you might need to change your furball’s food.

  • Age: Puppies need to transition to adult dog food at around the stage of their first birthday. This is slightly later if you have a bigger breed. Dogs are considered seniors aged 7. At this point, you should strongly consider switching Fido to a senior formula
  • Activity levels: If you have a working dog, or a dog that takes part in sporting events or agility events, you’ll need to ensure he eats food that supports these elevated activity levels. Foods designed for active dogs are high in protein and calorie content. You’ll need to switch away from this food if your dog’s activity levels drop or it could lead to unwanted weight gain
  • Overall health: If your dog has a health condition like GI issues, your vet may prescribe a formula to support this condition
  • Weight management: If your dog is outside his healthy weight range – this differs from breed to breed – your vet may recommend a dog food for weight loss. That said, many weight changes can be addressed by simply adjusting portion size rather than switching foods. Speak with your vet to establish the most effective plan

I. How to Safely Switch Your Dog’s Food While Avoiding Stomach Upsets

If you suddenly change your dog’s food, you could cause gastrointestinal upsets, including explosive diarrhea and vomiting. You might also find your dog’s appetite seems to dip, especially if he isn’t too keen on the new food.

Dietary changes should be executed gradually over a ten-day period to avoid triggering these outcomes.

Here is a blueprint for making that change the right way:

  • Days 1 to 3: 25% new food, 75% old food
  • Days 3 to 5: 50% new food, 50% old food
  • Days 5 to 8: 75% new food, 25% old food
  • Day 10: all-new food

If your dog has a sensitive stomach, GI conditions, or food allergies, you might need to extend this transition period accordingly.

Whenever you’re changing your dog’s food, closely monitoring his response to the change is vital. If you pick up on any signs like decreased appetite, diarrhea, or vomiting, you should dial back the speed of the transition.

If, on the other hand, you follow these steps and find your dog is still experiencing stomach issues, you should schedule an appointment with the vet. You might need to explore a different diet for your fur baby.

What, then, causes dogs to have adverse reactions to food?

II. Why Dogs Have Adverse Food Reactions

Often, pet owners speak of their dogs having food allergies when in reality they do not have a legitimate allergy. A true food allergy occurs when you’re dog’s immune system responds to a specific ingredient.

An adverse food reaction is an umbrella term used for allergies, intolerances, and insensitivities.

In the event of an adverse food reaction in dogs, expect either cutaneous symptoms, gastrointestinal symptoms, or both.

Cutaneous symptoms include:

  • Hair loss
  • Itching
  • Rashes
  • Skin inflammation

Gastrointestinal symptoms include:

  • Changes in appetite
  • Diarrhea
  • Nausea
  • Vomiting

Many illnesses also cause the above symptoms, so you should liaise with your vet to rule out any underlying health conditions.

If your vet suspects your dog is presenting with an adverse reaction to food, the first option is often trialing an elimination diet. This means that for a two-month period, your dog will eat nothing but a hypoallergenic prescription diet. This eight-week spell should be enough for symptoms to dissipate if food was the reason underpinning the reaction.

Once an elimination diet trial is complete, a challenge trial sees you reintroducing certain foods to determine whether they provoke a reaction. This can help you and your vet double down on any foods that irritate your furball so you can avoid them moving forwards.

To round out today, we’ve assembled some general pointers that should inform any changes you make to your dog’s diet.

III. 5 Handy Hints for Switching Your Furball’s Food

The following pointers may come in handy when you need to make age-related food changes.

  1. You should transition your dog from puppy food to adult food around his first birthday. This is essential to give your mutt all the nutrients he needs during the growth stage of life.
  2. If you have a large breed or giant breed, you should switch them to a breed-specific dog food catering to their distinctive dietary requirements.
  3. As small and medium-sized dogs hit the age of 7, think about shifting them to a senior formula designed to cater for their changing needs. For large breeds, you should make this change at the age of 5.
  4. If your dog is pregnant or nursing, she will need food with a heightened calcium content. When large breeds are pregnant, you should transition them to a standard puppy food rather than a large breed puppy food.
  5. When you need to change your dog to a prescription diet, consult closely with your vet. You could need to take some special considerations into account when you’re swapping his food.


We very much hope today’s guide to changing your dog’s diet has cleared up some of the common issues new pet owners face in this area.

Take your time and be sure to avoid abrupt changes to your dog’s food. Use the ten-day framework and guidelines for altering the ratio of old to new food and you should sidestep all the GI issues sudden switches can trigger.

Bookmark BarkVA before you head off today and be sure to pop back soon. We have a busy content slate for the coming months so don’t miss out!

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Jesse Hopping, CCDT

Jesse is a natural-born dog-lover certified dog trainer (CCDT), dog foster, and former volunteer at Richmond SPCA and surrounding dog shelters for over 10 years. Her pack includes a Bernedoodle and 3 Boston Terriers. She’s sipping caramel coffee and watching her pack play in the sun when she’s not writing blogs. Jesse has her Certified Dog Trainer designation from CATCH Canine Trainers Academy since 2018 and and majored in English from the University of Virginia.

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