NutriSource Blogs

When to switch to adult dog food: A puppy parent’s guide to making the transition

April 15, 2023

Just like children, puppies experience a lot of milestones as they get older. From becoming fully potty trained to learning basic commands, there are a lot of moments that make a dog owner proud. But there may be no surer sign that your puppy is growing up than when they make the switch to adult dog food. Like humans, dogs have different nutritional needs at different stages of their lives, from puppies to adults to senior dogs. But many dog owners wonder when and how to make the switch without causing digestive issues or other negative outcomes. Here’s a guide on making the transition from puppy food to adult dog food while ensuring your dog gets all the nutrition they need.

When to switch puppy to adult food

Puppies require different nutrition than adult dogs, which is why puppy dog food formulations are geared specifically toward promoting healthy tissue growth. So, you don’t want to make the switch too early or you could impact their development. It’s generally better for dogs to stay on puppy diets too long than it is to make the switch too soon.

The consensus among veterinary professionals is that puppies should switch to adult dog food when they have “matured,” or reached roughly 80% of their adult size. But maturity can be hard to gauge, and with mixed breeds, it’s not always clear what their final size will be.

So, deciding when to switch your dog from puppy to adult food depends on a variety of factors. Those include their breed size, whether they’ve been spayed or neutered and their activity level.

Small, medium or large breed

Small breeds – Small-breed dogs reach maturing the fastest, typically between 10 to 12 months in age. So, experts recommend switching to adult food when they are around 9 to 10 months old. However, some small-breed dogs may be able to switch to adult food as soon as 7 to 9 months, depending on their size.

Medium breeds – Medium-sized dogs tend to be fully grown between 12 and 15 months. Likewise, vets recommend making the switch to adult dog food in that same 12- to 15-month period.

Large breeds – Large-breed dogs take the longest to fully mature. Some can reach adult size at around 15 months, while others may take as long as 24 months. So, depending on your dog’s exact breed, you may want to consider switching to adult food between 14 and 24 months. For specific questions about your dog, it’s best to consult your veterinarian.

Spayed or neutered

One critical factor in determining when to switch from puppy to adult food is whether your dog has been spayed or neutered. In general, a dog’s calorie requirements drop off after they have been spayed or neutered. However, in most cases, spaying or neutering does not impact a dog’s overall growth. So, depending on when you get your dog spayed or neutered, and how close that is to when they reach 80% of their adult weight, you may consider switching to adult food following the procedure to prevent overfeeding with the higher calorie puppy food.

Activity levels

Some dog breeds, regardless of their full adult size, just seem to have more energy and exhibit higher levels of physical activity than other breeds. For these “athletic” dogs, it may be wise to maintain a diet of puppy food slightly longer before making the switch. This is because the higher levels of protein in puppy food formulations can promote the muscle development they need to enjoy their active lifestyle.

How to transition my puppy to new food

To make the transition to adult dog food as smooth as possible, it’s best to make the switch gradually. This may take a week, or at least a few days. Mix in a small amount of adult dog food with their puppy food, and slowly transition so that the mixture gradually becomes more adult dog food than puppy food over the course of the week. This will help avoid stomach irritation or other digestive issues.

Making sure your dog gets the best nutrition

Feeding your dog a single protein–based diet (such as only feeding them beef-based dog food formulations) can lead them to miss important nutrients and can contribute to the development of food sensitivities. So, transitioning your puppy to adult dog food is a great opportunity to also start practicing Full Circle Feeding. This involves cycling in different types of proteins, grains and vegetables to ensure your pet gets all the nutrients they need to be at optimal health. To learn more, check out our Ultimate Guide to Full Circle Feeding.


Still have questions about making the switch? Here are some answers to the most frequently asked questions.

Can a puppy eat adult food?

Yes, they can, but it isn’t recommended. Puppy food is specifically formulated to provide the right type of nutrition for a growing dog. Feeding a puppy adult dog food could cause them to miss out on nutrients that are important for healthy development.

Is puppy food bad for adult dogs?

Puppy food isn’t necessarily bad, but it isn’t formulated for their specific needs. Puppy food tends to be higher in calories and proteins, which could contribute to obesity in adult dogs if they continue to eat it as their calorie requirements drop as they age.

What’s the difference between puppy and adult dog food?

The biggest difference between puppy and adult dog food is that puppy food is formulated with extra calories and proteins to promote strong tissue development and overall growth. Adult dog food is formulated to help adult dogs maintain a healthy weight and provide the nutrition they need to lead a healthy lifestyle.

Shop local and buy both puppy and adult NutriSource dog food products from one of the independently owned and operated pet suppliers in your community.