How to Switch Cat Food Without Stomach Upset

Switching cat food is sometimes necessary, due to picky eating, changes in your cat’s nutritional needs, food sensitivities, or food recalls. However, changing foods too quickly can cause an upset stomach and even progress to dehydration and food refusal. The safest approach is a gradual transition over 7–10 days.

In this article, we’ll give you a step-by-step transition plan for how to switch cat food without stomach upset. We’ll also teach you how to tell the difference between normal food adjustments and potential medical issues

Here at Tuft & Paw, we’re cat experts. We have intimate knowledge about the cat food features that appeal to both cats and their parents. The information in this article is based on consultation with a veterinarian and a pet nutritionist, extensive online research, and our real-world experience as cat parents.

Why Cat Food Should Be Switched Gradually

Cats have sensitive digestive systems, as their gut microbiome is adjusted to their current eating routine. Different foods contain varying levels of protein, fat, fiber, and moisture. A sudden change gives digestive bacteria little time to adapt, which may lead to temporary digestive upset. Whether you’re switching brands, flavors, formulas, or textures, it’s best to do so gradually to give your cat’s digestive system the time it needs to adjust. 

How to Switch Cat Food Without Stomach Upset: Step-by-Step

Most experts recommend introducing new cat food over a period of 7-10 days. This slow transition gives your cat's digestive system time to adapt and reduces the likelihood of stomach upset. When you’re switching your cat’s food, it’s best to do this at a time when there is no added stress in the household so the environment remains calm. Keep everything else about your cat’s meal setup the same, including the meal times, location, and dish, so that the food is the only change they’re experiencing.

While this is a good guideline, it’s not absolute. Cats with a history of sensitive stomachs or GI issues may benefit from a slower transition over 10-14 days. Cats who have eaten the same food for years may also need a longer transition. If your cat seems uninterested in their food or shows some mild digestive changes, revert back to old food for a week and restart the transition with a smaller amount of new food.

Dr. Jennifer Taketani, veterinarian and medical director at Corona Del Mar Animal Hospital, also notes that a cat may initially be excited about a new food but then refuse it 1-2 days later. This may be a sign of nausea, as the cat learns that the food makes them feel nauseous afterward, and the association causes them to refuse it. She recommends getting in touch with your vet if this happens to learn more about what might be going on. 

Same Bowl or Separate Bowls? Settling the Debate

Some experts say to mix old and new food in one bowl. Others recommend using two bowls: one for the new food and one for the old. The answer to which is best depends on your cat and their tendencies. Offering separate bowls can reduce your cat’s stress around the change and also gives them agency in letting you know which food they prefer. Pickier cats may benefit more from mixing food, as it gives them time to adjust to changes in smell and texture. 

Switching Between Food Types

Switching between food types can be a significant change for your cat, especially when it involves changes in texture or smell.

Transitioning Your Cat from Dry Food to Wet Food (And Vice Versa)

Switching between dry and wet food involves some pretty major changes in calorie density and texture. Because wet food is 70-80% water, your cat eats a larger volume of wet food than dry food. If you’re transitioning from wet food to dry food, your cat might not be pleased at how small their portion size looks. Adding water or broth to their kibble can help beef up the volume without adding calories. For texture issues, mixing the food together as you transition can help. You can also try placing a drop of wet food next to their dry kibble before introducing the wet food to give your cat time to adjust to the new scent before eating. 

Switching Protein Sources

Switching your cat’s protein source can spark interest in picky eaters, and in some cases, your veterinarian may recommend a new protein as part of a food allergy elimination trial. If you’re changing proteins, a gradual transition is often best. Heather Enajibi, a certified professional pet nutritionist and brand ambassador for Natural Pet Food Group, suggests offering small amounts of the new protein as freeze-dried treats to help build a positive association with the new food.

While Dr. Taketani acknowledges that rotating proteins can be beneficial for picky eaters, she points out that it isn't usually appropriate for cats with gastrointestinal sensitivities or food allergy dermatitis. Common symptoms of cat food allergies include chronic itching, recurring ear infections, excessive grooming, vomiting, diarrhea, or skin inflammation. Your veterinarian may recommend a prescription elimination diet to identify the offending ingredient. If your cat is on a veterinarian-recommended elimination diet, she advises checking ingredient labels carefully. “For example, some fish-flavored foods may include chicken by-products further down the ingredient list, which would hamper a strict diet trial as recommended by a veterinarian.”

Kitten to Adult Food

Kittens usually transition to adult food around 12 months of age, although large breeds may transition later. Like switching adult foods, a slower transition is best for cats with sensitive digestive systems. One important note is that adult food is less calorie-dense than kitten food because it’s designed to help maintain weight rather than support rapid growth. As you transition from kitten to adult food, keep an eye on your cat’s weight to ensure that you’re feeding them the proper portion size.

How to Switch Cat Food for a Picky Eater

Enajibi says that cats are often picky eaters because they rely on smell, texture, and past experiences to judge what’s safe and preferred. If your cat refuses new food, these tips for picky eaters can help make the transition less stressful while reducing the risk of stomach upset. 

• Warming the food slightly: Warming the food slightly can increase its aroma, which can make it more palatable for a picky eater. To warm your cat’s food, scoop the portion into a stainless steel or glass bowl and place this bowl in a warm water bath. Stir your cat’s food until it is warm to the touch. Alternatively, mix some warm water into your cat’s food. Some cats also prefer eating their food at room temperature.

• Try toppers: Cat food toppers, such as broth, gravy, and freeze-dried treats, can make food more appealing to picky eaters. However, use small amounts and stick with a topper your cat has enjoyed before to prevent stomach upset.

• Mix the food thoroughly: Ensuring that your cat’s old and new food are mixed thoroughly can help picky eaters transition to new smells and textures. This can also help prevent picky cats from eating around the new food.

• Offer regular mealtimes: Feed your cat on a consistent schedule so they learn to eat when food is offered. Fresh food is often more appealing, so remove any uneaten food after 20 to 30 minutes and offer a fresh meal at the next scheduled feeding. 

• Show patience: Dr. Taketani notes that, unlike most dogs, if a cat doesn’t like the food offered, they will go on a hunger strike to the point where it affects their health. If your cat is refusing their new food, switch back to their old food and try a more gradual transition. If your cat refuses to eat for 24 hours, contact your vet. 

• Playtime before meals: Offering your cat a little exercise before mealtime can help to increase their appetite so that they find their food more appealing.

• Avoid major transitions: Major changes in protein and texture can be overwhelming to picky cats. Unless recommended by your vet, try sticking with the same protein and offering a similar texture. For example, if your cat enjoys chicken chunks in gravy, try looking for another brand that offers chicken chunks or shreds in gravy.

What if Your Cat Has a Sensitive Stomach?

If your cat has a sensitive stomach, a slower transition of old to new food over 10 to 14 days works best. Every few days, gradually increase the amount of new food, as long as your cat isn’t having any stomach or behavioral issues. During this time, keep regular meal times and ensure that your cat has access to fresh water. Adding a probiotic can also help to support cat digestive health. 

The best cat food for sensitive stomachs often has one easy-to-digest protein. Good options include chicken, turkey, fish, or rabbit. You may also wish to look for added prebiotic fibers, such as psyllium husk, beet pulp, and flaxseed, which help to feed your cat’s healthy gut bacteria. Some cats with sensitive stomachs may also do better on wet food. Dr. Taketani points out that traditional kibbles, made by extrusion, are more processed, which can make them more difficult to digest. 

Transitioning in Multi-Cat Households

Transitioning cat food in multi-cat households can require a little extra planning. If only one cat is switching to a new food, you’ll want to set them up to eat in a separate room. To do this, start by feeding them their familiar food in their usual bowl in the new location. This helps them adjust to the new environment before you introduce the new cat food.

If all cats are changing to a new food, follow the same transition schedule for everyone to maintain consistency. You’ll also want to closely monitor your cats’ meals to ensure that all cats are eating and no cat is stealing another’s meal. 

When to Call the Vet

You may notice some mild changes in your cat’s digestion when switching food, such as increased gas and softer stool. However, more significant changes warrant a trip to the vet. These include:

• Not eating for 24+ hours

• Vomiting multiple times

• Blood in stool

• Severe diarrhea

• Dehydration, which may be noticed by pale, dry gums

• Rapid weight loss

Depending on your cat’s symptoms, your vet may recommend switching to a bland diet or prescribe anti-nausea medication to help your cat’s stomach settle. They may also run tests to determine if there’s any underlying cause of your cat’s symptoms.

The Bottom Line: How to Switch Cat Food Without Stomach Upset

Switching gradually is the best way to transition between cat foods without causing stomach upset. While most cats transition at a 7-10 day pace, cats with sensitive stomachs might benefit from a slower transition of 10-14 days. Adding in a probiotic and keeping regular feeding times can also help with the transition. If your cat does develop an upset stomach, contact your vet for more guidance.

Frequently Asked Questions About Switching Cat Food

How long does it take to switch cat food?

Most cats are able to switch cat food in 7-10 days. However, cats with sensitive stomachs or picky eaters might benefit from a longer transition period of 10-14 days.

What’s the best way to transition a cat with a sensitive stomach?

A slow transition over a period of 10-14 days is the best way to transition a cat with a sensitive stomach. Regular feeding times, probiotics, and offering plenty of fresh water can also support cat digestive health while your cat adjusts to a new diet.

What is the best cat food for sensitive stomachs?

The best cat food for sensitive stomachs includes a single, easily digestible protein, moderate fat levels, and added prebiotic fiber. Lean proteins, such as chicken, turkey, fish, and rabbit, are often easiest to digest. 

What if my cat refuses their new food?

If your cat refuses their new food, don’t let them starve, as this can increase the risk of liver damage. Heating your cat’s food up or adding food toppers can help entice them to eat. If they’re still not interested, revert back to their old food for a few days. Contact your vet if your cat refuses to eat for 24-48 hours.

Sources

American Animal Hospital Association, & American Association of Feline Practitioners. (2021). 2021 AAHA/AAFP feline life stage guidelines. Journal of Feline Medicine and Surgery, 23(3), 211–233. https://doi.org/10.1177/1098612X21993657 

Cornell University College of Veterinary Medicine. (n.d.). Feeding your cat. Cornell Feline Health Center. https://www.vet.cornell.edu/departments-centers-and-institutes/cornell-feline-health-center/health-information/feline-health-topics/feeding-your-cat 

VCA Animal Hospitals. (n.d.). 6 tips to help soothe your pet's tummy troubles. https://vcahospitals.com/resources/conditions-cat/stomach-digestion/6-tips-to-help-soothe-your-pet-s-tummy-troubles 

VCA Animal Hospitals. (n.d.). Hepatic lipidosis in cats (fatty liver syndrome in cats). https://vcahospitals.com/know-your-pet/liver-disease-fatty-liver-syndrome-in-cats