Dogs are by far the most commonly kept type of pet in the western world and the number of people adding a dog to their family is currently higher than ever.
Due to dogs being so popular, we see a wide range of questions about caring for a dog being asked from the community each month and one common question that we have seen lots recently is about feeding an adult dog puppy food if you accidentally bought puppy food.
Adult dogs can and will eat puppy food if you give it to them and in the majority of cases, there shouldn’t be any long term health risks to your adult dog.
That said, there can be some short term issues such as diarrhea and vomiting due to the change in the macronutrient ratio in the puppy food as well as the potentially different protein source.
Due to these potential problems often worrying dog owners and more and more dog food brands using very similar packaging for their puppy and adult dog food products making this issue more common, we wanted to publish this dedicated article on the topic to help our readers.
What’s Different About Puppy Food Compared To Adult Dog Food?
There are a number of differences between puppy food and adult dog food with the two main ones being a change in the macronutrient ratios with puppy food having more protein and fat as well as puppy food having DHA to help with growth.
DHA is a source of omega fatty acids found in the mother’s milk and should not cause issues for most adult dogs if they eat food that contains DHA unless the dog has issues with having dairy in their diet but more on that later.
The main issue that can cause is diarrhea and vomiting in your adult dog that is eating puppy food is the chance in the macronutrient ratio, specifically the higher fat content so let’s take a quick look at that.
The image above goes over the average macronutrient ratio of the average puppy food mix and the average dog food mix from the larger commercial dog food brands on the market right now.
In reality, these are actually in a range with puppy food usually having a range protein range of 22-32% and a fat range of 8-20% while adult dog food has a protein range of 15-23% and a fat range of 6-15% so we have only used averages in the pie charts above.
As you can see, puppy food tends to have a much higher ratio of protein and fat and a lower amount of carbohydrates than adult dog food to help your puppy grow.
The protein is to help the puppy grow healthy muscle and organs during its rapid growth phase where as the higher fat content is to help provide it with the energy it needs as 1 gram of fat contains 9 calories where as 1 gram of carbs contains 4 calories making fat a cheaper option.
Now, an adult dog can easily survive on this macronutrient ratio with ease and modern puppy food is actually much closer to the ratios of a dog’s ancestral diet than modern dog food but your dog’s gut bacteria takes time to adjust.
This is exactly the same for a human, our digestive system has a number of different types of bacteria in it with some that thrive on carbohydrates and others that thrive on fats and your dog is no different with a slight change in these ratios being able to cause diarrhea and vomiting in your dog.
If you have ever tried switching from a standard western diet that is high in carbs over to the keto or Atkins diet that is low in carbs and high in fat and protein, you will know that most people have diarrhea for around a week while their gut bacteria adjust.
This is why your adult dog may have temporary issues with diarrhea and vomiting when you first start to feed it the puppy food that you accidentally bought but this should be temporary. If the issues persist for more than a week then you should switch to your dog’s regular food and consider a check up at your local vet’s office.
Ancestral Diet Macronutrients
The image above goes over the macronutrient ratio of the ancestral dog diet and as you can see, it is considerably high in fat and protein than both modern puppy food and adult dog food and most healthy adult dogs can thrive on this macro ratio.
Dogs have evolved to be optimized for this type of macro ratio and puppy food tends to be closer to it than modern dog food mixes due to brands pumping the food mixes for adult dogs with cheap sources of carbohydrates to help keep their costs down.
There are a number of dog food brands out there like taste of the wild that try to optimize the macro ratio of their food mix to a closer ratio of the ancestral diet of a dog though.
As we covered in our article on if taste of the wild causes diarrhea, the rapid switch in your dog’s macro ratio can cause diarrhea and vomiting though just like an adult dog that is switched over to a puppy food mix and this is considered a normal temporary symptom.
Can Adult Dogs Eat Puppy Recipe?
The vast majority of healthy adult dogs are able to easily eat a puppy food recipe without having any serious long term issues but they may have problems with diarrhea and vomiting in the short term.
We often see people who have accidentally bought puppy food and opened the food bag before realizing worrying about feeding their dog the puppy food they have purchased.
In most cases, provided the protein source is the same as your dog would usually eat, there really shouldn’t be much of a problem after the first week of your dog eating the puppy food mix.
That said, if you do have to switch the protein source from say chicken to beef, then there may be problems with this too due to allergies so we will take a look at this in the next section.
Is It Bad If My Adult Dog Eats Puppy Food?
Many dog owners are surprised to discover that around 50% of all dogs have allergies to at least one common ingredient in modern commercial dog foods.
As we covered in our article going over if Orijen dog food causes diarrhea, this is why so many people have issues when changing their dog food brand with the issue actually being the chance in ingredients rather than one brand being better than the other.
The same can be true if you accidentally bought puppy food for and adult dog as many of the standard ingredients can be different to adjust the macro ratio as required.
If you have accidentally bought puppy food that has a different protein source than what your adult dog is used to, the chances of your adult dog having issues with diarrhea and vomiting increases too.
Here is a quick breakdown of the most common ingredients that dogs can be allergic to as well as how many dogs can have allergies to that ingredient.
As you can see, a surprisingly high number of dogs can have allergies to some very common dog food ingredients and many puppy food mixes contain dairy as the source of DHA omega acid.
If your dog has allergies to dairy then this single ingredient in the puppy food that you accidentally purchased can be enough to cause constant diarrhea and vomiting from your adult dog.
If you have accidentally bought puppy food that has beef as its primary protein source and your dog is used to chicken, lamb, pork or fish then the chances of your dog having diarrhea and vomiting is also higher due to so many dogs being allergic to beef.
This is why the majority of limited ingredient dog foods on the market that have been designed for dogs with allergies are usually rice and fish or rice and pork due to so few dogs having allergies to them.
If your adult dog does have allergies to one of the ingredients in the puppy food that you accidentally purchased then the diarrhea and vomiting will usually last as long as your dog is eating that food mix rather than just be temporary like the diarrhea and vomiting caused by the macronutrient ratio change.
Should I Change Anything In My Dogs Diet While It Is Eating Puppy Food?
The majority of dogs will be fine on the macronutrient ratio of puppy food without having any long term problems but some dog owners can try to mix the food mix with cooked rice or mashed sweet potato to normalize the macro ratios of the food.
This is more difficult to do than most people realize though but it can be a quick, easy, and cheap way to boost the carbohydrate content of your dog’s diet and lower the protein and fat ratio while it is eating the puppy food mix that you accidentally purchased.
In our opinion, this is not needed and most people will not need to try and normalize the macronutrient ratio of the food.
If you do choose to try this though, rice or sweet potato are definitely the best options due to their low allergin ratio while also being cheap, easy to prepare, and easy to find in most stores.
Some people also add pumpkin but depending on the time of year, this can be very expensive or difficult to find.
If your dog has allergies to one of the ingredients in the puppy food that you accidentally bought then there’s nothing that you can add to the food to counter this and most people will just have to take the hit and order their dogs normal food mix.
What Happens If You Keep Your Dog On Puppy Food?
In most cases, a healthy dog can actually stay on puppy food indefinitely but the higher fat content does mean puppy food contains more calories so you will have to monitor your dog’s weight for again weight gain.
As we mentioned earlier in the article, most commercial puppy food mixes on the market right now are actually closer to your dog’s ancestral diet macro ratio breakdown than the food mixes designed for adult dogs.
Rather than keep your dog on a puppy food once it reaches maturity, we would usually recommend that you just move onto a brand like Taste Of The Wild that has closer ratios to your dog’s ancestral diet than go with puppy food.
You will usually find that a brand like Taste Of The Wild offers a similar macronutrient profile while usually being cheaper than puppy food due to not having to supplement DHA and other boosters to help your puppy grow.
Can I Return Any Accidentally Bought Puppy Food To The Store?
If you have accidentally bought puppy food and not opened the bag yet then most stores will allow you to return the puppy food and exchange it for an adult dog food mix without issue.
If you have opened the puppy food that you accidentally purchased then you will usually just have to feed the puppy food to your adult dog or write the cost off and purchase the correct food mix.
As we have explained above though, in many cases, an adult dog should be totally fine on a puppy food mix after its first week so many of our readers who have accidentally bought puppy food for their adult dog will be able to feed the puppy food to their dog as normal without any real issues.