How to Transition to New Dog Food

Perhaps you just adopted a dog or are switching your puppy to adult food. At some point, changing their food will be on your checklist of things to do. Your dog needs food that will meet their needs, and these needs can change based on their age, size, breed, activity, allergies, and health status. 

To do this properly, you should slowly get your dog used to the new food while gradually weaning them off their old food. Knowing how to do this can help them avoid an upset stomach or food aversion that comes with a sudden transition. It will ultimately ensure your dog is getting the nutrition they need.

Benefits of a slow transition to new dog food

“Switching food slowly allows time for the GI tract to adjust to the new food and its ingredients. It allows you to see if the new food is going to cause any reactions that could make your pet really sick,” says Dr. Heidi Cooley, a veterinarian at Banfield Pet Hospital. 

Sudden dietary changes can cause your puppy or adult dog to vomit, have diarrhea, and even refuse to eat, so a gradual transition is best if you want to avoid these issues. Vomiting and diarrhea can result in dehydration, not to mention messes for you to clean up. Meanwhile, food avoidance can become troublesome if your dog develops into a finicky eater. 

Slowly transitioning your dog’s food will help prevent these issues from occurring and allow your dog to adjust to the new diet.

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Reasons to transition your dog’s food

When it comes to dog food, one size does not fit all. A variety of factors can influence which dog food is best for your dog. They should all be discussed with your veterinarian.

1. You may need to change a dog’s food as they age

Depending on their age, dogs require different nutrients, which is why some dog food is formulated for particular life stages. The Association of American Feed Control Officials (AAFCO) offers guidelines for manufacturers to formulate food for different life stages, including gestation/lactation formula, puppies for growth, adults for maintenance, and food for all life stages. Although there are no AAFCO guidelines for senior or aging dogs, many manufacturers do offer food formulated for older canines. You should feed your dog an age-appropriate formula whenever possible.

2. You may need to switch a dog’s food due to sensitivities and allergies

Just like people, dogs can react negatively to different foods if they have food sensitivities or allergies. If this is the case for your dog, you may need to feed them a diet that doesn’t contain a specific ingredient. These diets may be called prescription or therapeutic diets and are specially formulated to provide appropriate nutrition while also avoiding a certain ingredient (or ingredients).

3. You may need to transition a dog’s food due to their weight

If your dog is severely underweight, overweight, or in need of food to maintain their weight (due to a high activity level), a food change may help. Some food may be more calorically dense and contain higher levels of fat to encourage weight gain, while others may be low-fat or contain fewer calories per serving to aid in weight loss. No matter which way you want the scale to go, food is a key player when it comes to your dog’s weight.

4. You may need to change a dog’s food due to health issues

If your dog is diagnosed or predisposed to certain health issues, a special food may be recommended by your veterinarian. These special foods may contain added ingredients that traditional diets do not contain, or they may have different vitamins, minerals, fats, proteins, or other ingredients to help support certain bodily systems. Depending on the health issue being addressed, the food’s consistency, shape or texture may also be a reason to feed it to your dog — like, when they have no teeth and can’t chew, have a feeding tube that requires a liquid diet, or are prone to dental disease and need food designed to reduce plaque.

5. You may need to change a dog’s food due to breed

Some research has shown that certain dog breeds may benefit from food that supports their unique metabolisms and nutrient requirements. As your dog grows and matures, a breed-specific diet may be beneficial.

Steps for transitioning your dog’s food

“Start with a smaller volume of food than a normal diet. You can ask your regular vet if they advise mixing in white rice or a prescription gastrointestinal diet to aid with transition,” Dr. Cooley explains.

So, how long does it take to switch dog food? Dr. Cooley says you can expect this transition to take anywhere from eight to 12 weeks. A week is a good, basic timeframe for your dog’s body to fully adjust to a new dog food. But this will vary — the slower the transition, the better. If your dog is a picky eater or has a sensitive tummy, it may take them more time to adjust.

Seven-day food transition plan

To make the transition to a new dog food easier, you’ll want to follow a few simple steps.

1. Determine the new diet: The first step in transitioning your dog to a new food is to determine what the new diet will be. Work with your veterinarian to decide which food is best for your dog based on their age, breed, weight goals, health issues, and any allergies or sensitivities.

2. Plan the transition timeline: Once you have determined which food you will be transitioning your dog over to, plan out the food ratio and timeline.

3. Gradually introduce new food: Dr. Cooley recommends gradually increasing the percentage of new food, while decreasing the percentage of old food, over seven days. Throughout this transition timeline, you can gradually introduce the new food into your dog’s current diet. 

• Day 1: Start by feeding 75 percent of your dog’s old food and 25 percent of your dog’s new food.

• Day 4: Feed your dog 50 percent old food and 50 percent new food.

• Day 7: By the end of the week, 100 percent of the new food and 0 percent of the old food.

4. Monitoring Your Dog’s Response: Watch for any vomiting, diarrhea, food aversion, or skin changes as you change dog food.

14-day transition plan

The 14-day transition plan is similar to the seven-day transition plan, except that the change in food is even slower. If your dog has an especially sensitive stomach, a longer transition period may be beneficial. A 14-day transition period is less likely to cause GI upset and food aversion.

Special considerations

If you are transitioning your dog from dry food to wet food (or one that is known to be less flavorful) or if your dog is a picky eater (or has a sensitive stomach), you may need to take the transition more slowly than usual.

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Signs of a successful transition

If you’ve weaned your dog off their old food and entirely onto a new food, there are a few signs that this transition has been successful.

• First, your dog is willingly eating the new food on their own. 

• Second, there has been no vomiting. 

• Third, your dog’s poop is formed and normal.

In contrast, vomiting, diarrhea, and food aversion can occur if the transition has been done too quickly. These symptoms, alongside dry, itchy, or red skin, can also indicate a negative reaction to the food. 

When to consult with a veterinarian

“Monitor for diarrhea, vomiting, constipation, increased gas, and a change in appetite,” Dr. Cooley says. If you notice your dog negatively reacting to a new food — and these reactions last for more than 48 hours — contact a veterinarian to discuss your options. They may recommend that you stop giving your dog the new food.

Troubleshooting when switching foods

Can you switch dog food flavors of the same brand?

Yes, you can switch dog food flavors of the same brand, but you should still try to transition the foods slowly. Even though it’s the same brand, different flavors mean different ingredients.

When should I switch my dog from puppy food?

Small dog breeds can be switched to adult food between nine and 12 months of age, but larger breeds may need to stay on puppy food until they are 18 to 24 months old. “You should ask your veterinarian, as it depends on breed and your particular pet’s weight as well as maturation. Usually, it can be as early as eight months and as late as two years,” Dr. Cooley explains. Discuss when to change to adult dog food with your veterinarian.

How bad is it to switch dog food quickly?

Although it’s not the end of the world to change dog foods quickly, switching without mixing can cause issues. Some dogs are not bothered by dietary changes, but most will experience some vomiting, diarrhea, or food aversion with a sudden switch in food.

Any special considerations when switching from dry food to wet food vs. kibble to kibble? 

Since wet food contains more moisture than dry food or kibble, it is more likely to cause your dog to have diarrhea than if you transition from one kibble to another kibble. You may need to slow the transition period down if you begin to notice your dog’s poop is softening.

Any tips for transitioning dog food when you don’t have the old food?

If you’ve already run out of your dog’s old food and need to transition your dog to a new food, you may want to add in pre- and probiotics as well as fiber sources to help decrease negative reactions. Talk to your veterinarian about which options might be best for your dog.

Food to support your dog’s gut health

Some dog foods will include ingredients to support your dog’s gut health. These may include additional fiber sources, prebiotics, and probiotics. These ingredients can also be added to your dog’s food to help prevent digestive issues and improve gut health if your veterinarian recommends them.

References

“How Do I Switch My Pet’s Food? – Petfoodology.” Tufts.edu, 25 Nov. 2019, sites.tufts.edu/petfoodology/2019/11/24/how-do-i-switch-my-pets-food.

“How Long to Feed Puppy Food & When to Switch to Adult Dog Food.” Purina.com, 2017, www.purina.com/articles/dog/puppy/feeding/how-long-to-feed-puppy-food. 

Llera, Ryan , and Cheryl Yuill. “Nutrition - General Feeding Guidelines for Dogs.” VCA Animal Hospitals, 2009, vcahospitals.com/know-your-pet/nutrition-general-feeding-guidelines-for-dogs.

Pescuma, Mariana Gilbert, et al. “Dog Breed and Starch Gelatinisation Correlation in Food Digestibility and Faecal Traits.” Journal of Animal Physiology and Animal Nutrition, 1 Oct. 2024, https://doi.org/10.1111/jpn.14047. 

Pet, Understanding. “Expert Q&A: Understanding Pet Food.” School of Veterinary Medicine, 6 May 2024, www.vetmed.wisc.edu/expert-qa-understanding-pet-food.

“Re-Evaluating Your Dog’s Diet | Cornell University College of Veterinary Medicine.” www.vet.cornell.edu, www.vet.cornell.edu/departments-centers-and-institutes/riney-canine-health-center/canine-health-information/re-evaluating-your-dogs-diet. 

“Selecting the Right Pet Food.” AAFCO, www.aafco.org/consumers/understanding-pet-food/selecting-the-right-pet-food.