If you've ever seen a dog chow down on the contents of an overturned trash can, you might be tempted to think all dogs have iron stomachs. The reality, however, is that dogs can be sensitive to what they eat and changing dog food abruptly can cause nausea, soft stool and loss of appetite.
Whether you just brought home a new pup or you need to switch your existing dog's food, here's how to do it without causing them discomfort.
If you just adopted a new dog, remember that this can be a stressful time. To minimize the number of changes they'll need to adjust to, for the first week or so, stick with the same food they were eating before you adopted them. This may help them feel more at home in their new digs — which is just as good for their emotional health as it is for their digestion.
Find out as much information about your dog's meals as you can from the shelter or previous pet parent, including the brand and type of food and how much and how often they were fed. Ideally, the shelter will provide you with enough food for your pup's first week. If not, pick up a small bag before bringing your dog home. Once they seem comfortable in their new environment, you can gradually transition their food to your preferred option.
While especially important for new dogs, any transition between dog foods should be handled gradually. Abrupt changes may result in gastrointestinal disturbances, which can compromise your dog's health and comfort. To avoid this, slowly transition your dog to any new food over a period of several days. A good rule of thumb is to add a little more of the new food while reducing the old food over the course of a week. Follow this general guideline when changing dog food:
Days 1-2: Mix 25% of the new food with 75% of the old.
Days 3-4: Mix 50% of the new food with 50% of the old.
Days 5-6: Mix 75% of the new food with 25% of the old.
Day 7 and onward: Feed your dog 100% new food.
Keep a close eye on your dog's response to their new food during the transition period. In addition to signs of stomach upset, such as vomiting or rejecting the new food, monitor their stool. If it appears runny or abnormally soft, return to a recent old-to-new ratio that did not upset their stomach and make smaller incremental changes, extending the transition period to two weeks. If their signs still don't resolve, contact your veterinarian.
In some cases, a dog may not tolerate a new food no matter how slowly you go, and that's OK. They may not like the taste or texture of their new dog food, or they might have an allergy or intolerance to one of the formula's ingredients. Your vet can help you determine whether this might be the case and recommend a solution. In the meantime, stop feeding your dog the new food entirely and shift them back to what they were eating before the transition.
In these situations, it's always best to reach out to your vet for advice. They may recommend bringing your dog in for a checkup to rule out any underlying health concerns.
What if your new dog's previous food is unknown to you, it's on recall or you simply can't get your hands on it? In these cases, introduce your dog to their new food slowly by feeding them small meals every four to six hours, keeping an eye out for signs of trouble in between meals.
Your dog's nutritional requirements will change over time, and you shouldn't be afraid to update their formula to ensure they're getting what they need. By slowly transitioning your dog to new foods, you can avoid stomach issues commonly associated with abrupt food changes and make the change easier on you and your canine companion. Always make sure to provide access to fresh, clean water as well, and don't hesitate to contact your vet for additional guidance.
Dr. Sarah Wooten graduated from UC Davis School of Veterinary Medicine in 2002. A member of the American Society of Veterinary Journalists, Dr. Wooten divides her professional time between small animal practice in Greeley, Colorado, public speaking on associate issues, leadership, and client communication, and writing. She enjoys camping with her family, skiing, SCUBA, and participating in triathlons.
Hill's Science Diet Adult Variety Pack
Science Diet's breakthrough nutrition supports ultimate digestive well-being & healthy microbiome
Science Diet's breakthrough nutrition supports ultimate digestive well-being & healthy microbiome
Chicken & barley entree with great taste and precisely balanced nutrition to support 5 essential building blocks for lifelong health
Chicken & Rice Stew with great taste and precisely balanced nutrition to support 5 essential building blocks for lifelong health
Supports healthy immune system, digestion, lean muscle & beautiful coat
Over 70% of dogs lost weight within 10 weeks when fed this nutrition
Clinically proven kibble technology to reduce plaque & tartar build-up
Hill's Science Diet Sensitive Stomach & Skin dry dog food is gentle on stomachs while nourishing skin & promoting a lustrous coat.
Supports digestive health, nourishes skin and promotes a lustrous coat
Over 70% of dogs lost weight within 10 weeks when fed this nutrition
Gentle on stomachs while nourishing skin & supporting development in growing puppies
A delicious complement to the nutrition of Science Diet Small & Mini dog food
A delicious complement to the nutrition of Science Diet dry dog food
Supports lean muscle, for dogs who prefer smaller kibble
Supports energy & beautiful coat. Helps keep immune system, joints, heart & kidneys healthy
A delicious complement to the nutrition of Science Diet dry dog food
Supports energy level & beautiful coat. Helps keep immune system, heart & kidneys healthy
Supports healthy joints, lean muscle, and beautiful coat for large breed dogs
Hill's Science Diet Sensitive Stomach & Skin dry dog food is gentle on stomachs while nourishing skin & promoting a lustrous coat.
Who knows what dogs do when you're not home? Here are some of the most common activities your pet will take part in while you're away.
Learn more about sled dogs and their role in today's wilderness treks, as well as their rich history helping to settle the Alaskan frontier.
Learn some effective ways to train your puppy, including home, group, and professional training, with these five helpful tips.
Learn why your dog might be eating his own stool or the poo of other animals. Find out what you can do to try and change this behavior in your dog.
How to Keep Dogs Active in Winter
As your dog ages, arthritis and joint pain can become more common. Learn what causes these issues, signs to look out for, and treatments options.
Discover why dead spots in your green lawn could be caused by dog urine, and learn steps you can take for getting your lawn (& dog) back into shape.
Learn the common signs that a dog is having joint problems, how joint issues occur & why they can so painful for him, as well as how they can be treated.
Learn whether soy is a safe ingredient in dog foods, if there are any health benefits or concerns, as well as if they can have products like soy sauce.
Dog bitten by pesky insect? Learn how to identify common bug bites on your dog, including ticks, mites, fleas & mosquitoes, and how they can be treated.
Learn how you can help your dog recover from ACL surgery, including tips for their activity, medications and nutrition.
Determine the human year equivalent of your large or giant breed dog as their size plays a much larger role in their aging than smaller dogs.
Seasonal allergies can affect dogs just like humans, but with a few preventative measures & testing or medicine, you can get these issues under control.
Learn what causes that wet dog smell, and what you can do to help reduce it overtaking your car, as well as how to get rid of it.
Periodontal disease in dogs is a common and painful problem. Learn how to spot symptoms to help you treat and prevent it from affecting your pet's health.
If you're thinking of taking your dog to the beach, you'll want to plan ahead. Learn some essential supplies to bring, as well as tips to keep him safe.
Your dog is a descendent of the mighty wolf, a noble hunter and confirmed carnivore. You feed him meals of the best possible quality, so why does he insist on eating grass?
Learn the importance of feeding your puppy or adult dog the right amount of food at proper intervals and find out what feeding method is best for your dog.
Are you wondering "Why does my dog hide their face?" Learn what your dog might be trying to tell you and whether you should be worried about the behavior.
Learn the types of gastroenteritis in dogs, the various ways symptoms that can show up, treatment options and when it's serious enough for a vet visit.
Our low calorie formula helps you control your dog's weight. It's packed with high-quality protein for building lean muscles, and made with purposeful ingredients for a flavorful, nutritious meal. Clinically proven antioxidants, Vitamin C+E, help promote a healthy immune system.
Our low calorie formula helps you control your dog's weight. It's packed with high-quality protein for building lean muscles, and made with purposeful ingredients for a flavorful, nutritious meal. Clinically proven antioxidants, Vitamin C+E, help promote a healthy immune system.
©2025 Hill's Pet Nutrition, Inc. As used herein, denotes registered trademark status in the U.S. only; registration status in other geographies may be different. Your use of this site is subject to the terms of our Legal Statement. About our Ads. Cookie Consent Tool