What to Feed a Pet When You Run Out of Food: The Two Directions Are Not the Same Risk

The bag is empty, the roads are closed or the shelves are, and there is a second animal in the house whose food is still in the cupboard. That is the moment this page is written for, and it is a different moment from the one where you are choosing what to buy. The question in front of you is not which format keeps best. It is whether the thing you already own can go in the other animal’s bowl tonight, and for how long, and what happens if you guess wrong.

Here is the short version of what the sources actually support. The two swaps are not mirror images. A cat eating dog food and a dog eating cat food are described very differently in the veterinary literature, and only one of those directions has a named list of missing nutrients attached to it. Meanwhile the number everyone wants, the number of days, does not appear in any of the primary sources we opened. That absence is the most useful thing on this page, because the confident day counts circulating online have to come from somewhere, and when we traced one of them it evaporated.

Everything below is quoted from a document you can open yourself, with the date we read it. Where a source will not support a claim, the claim is not here.

Before Anything Else: Six Households This Page Cannot Help

Substitution guidance is only safe for a healthy adult dog or cat on an ordinary over-the-counter food. If any of the following describes your animal, the routing is to a veterinarian, and it is not a formality.

An animal on a therapeutic or prescription diet. Renal, hepatic, urinary, gastrointestinal, hydrolyzed or allergy, weight-management, cardiac: for these, a substitution is not a downgrade, it is a change to a treatment. Tufts University’s Clinical Nutrition Service, in an article by Lisa M. Freeman, DVM, PhD, DACVIM (Nutrition) dated May 3, 2021, puts it plainly: “An abrupt change in diet may also be harmful to your pet if they are on a therapeutic diet for a medical condition.” The same article goes further about the well-meant suggestion you will get at a store counter, advising owners to check with a veterinarian about any alternative a retailer suggests, because “While these recommendations may be well-meaning, they can sometimes be dangerous for your pet!”

There is a regulatory reason these diets sit behind a veterinarian at all, and it is worth knowing because it explains why nobody, including this page, can name a swap for you. FDA’s Compliance Policy Guide Sec. 690.150, issued April 2016 and marked content current as of 11/06/2024, describes the factors under which FDA is less likely to take enforcement action against pet foods marketed to treat or prevent disease. The first factor on its list is that “The product is made available to the public only through licensed veterinarians or through retail or internet sales to individuals purchasing the product under the direction of a veterinarian.” The guidance explains the reasoning directly: “Because these products have not been evaluated for safety and efficacy, veterinary oversight is especially important to provide periodic assessment of how the animal is reacting to the diet and to discontinue the product’s use when warranted.” Note that this document carries the header “Contains Nonbinding Recommendations” and states of itself that it “does not establish any rights for any person and is not binding on FDA or the public”, so it describes FDA’s thinking rather than a rule you can cite at a counter. What it does establish is that the veterinarian is structurally in the middle of that product category by design.

Puppies and kittens, and pregnant or nursing animals. These are separate nutrient profiles, not smaller versions of the adult one. AAFCO’s own consumer page states that the recognized life stages are gestation and lactation, growth, maintenance, and all life stages, and that “Different quantities and ratios of nutrients as well as different feeding rates are ideal for different life stages.” An adult maintenance food is not a growth food, and a growth food is not a stopgap for an adult on a weight-controlled diet. Our kitten evacuation go-bag and puppy emergency kit pages cover the packing side of that, and the pregnant or nursing pet evacuation guide covers the rest.

Diabetic animals on fixed insulin timing. For dogs, the AAHA diabetes guidelines state: “Dogs with DM can do well with any diet that is complete and balanced, is fed at consistent times in consistent amounts, and is palatable in order to achieve predictable and consistent intake.” Read the operative words. Consistent times, consistent amounts, predictable intake. A substitution disturbs all three at once, which is exactly why it belongs in a phone call rather than a decision at the bowl. A currency note on that quotation: it comes from the 2018 AAHA Diabetes Management Guidelines for Dogs and Cats in the PDF that carries updates made in 2022, and AAHA has since split its diabetes guidance by species. The 2026 AAHA Diabetes Management Guidelines for Cats were published in the Journal of the American Animal Hospital Association, 2026, volume 62, issue 3 (automated request to aaha.org returned HTTP 403; read in a browser session August 11, 2026). The dog sentence quoted above is from the canine section of the guidelines that were AAHA’s current canine document on the day we read them.

Cats do not carry the same timing constraint as that dog sentence. The 2026 feline guidelines’ own dietary-management section states plainly: “Meal feeding is not essential but preferred.” and “It is ideal to use meal feeding with intermediate-acting insulins that peak within a few hours of injection; however, this is not essential in cats and graze eating over the day is acceptable.” What the same section asks for instead is reliability and composition, not a clock: “Prioritize a patient’s reliable food intake from a complete and balanced diet over modifying specific nutrients” and “Manage protein and carbohydrate intake to minimize postprandial hyperglycemia.” So for a diabetic cat, a dog-food swap is not chiefly a timing problem the way it is for the dog sentence above. It is a composition problem: it changes the protein and carbohydrate levels the cat’s glycemic regulation is built around, on food that was never formulated to hit them. That is still a call to the prescribing veterinarian before you fill the bowl, for a different reason than the dog paragraph gives. Our insulin cooler and diabetic pet kit page handles the drug side of the same emergency.

An animal with a diagnosed food allergy or intolerance. The whole point of the diet is the ingredient list. A substitution reopens it.

Any animal already showing signs. Vomiting, diarrhea, refusal to eat, lethargy, labored breathing, weakness, disorientation or a painful abdomen are not a feeding question. They are a call to a veterinarian or an emergency clinic.

Every species that is not a dog or a cat. Every source on this page is about dogs and cats. Rabbits, guinea pigs, birds, reptiles, small mammals, chickens, horses and livestock have different digestive systems and different failure modes, and nothing here transfers to them. The ASPCA Animal Poison Control Center makes one of those differences unmistakable in a single entry: avocado, it writes, is “primarily a problem for birds, rabbits, donkeys, horses and ruminants including sheep and goats”, with the biggest concern being “cardiovascular damage and death in birds and rabbits.” ASPCA scopes the biggest concern to birds and rabbits; it does not clear avocado for dogs, and avocado stays on the never-list below regardless of species. If you keep those animals, start at our rabbit and small pet emergency prep, guinea pig evacuation kit, bird and parrot emergency preparedness or horse and livestock evacuation basics pages, and call a veterinarian who treats that species.

The Asymmetry, in the Sources’ Own Words

Owners tend to hold both swaps in their head as the same kind of compromise. They are not, and one sentence in a named veterinary reference sets out the difference.

The Merck Veterinary Manual’s professional article on dog and cat foods, authored by Sherry Lynn Sanderson, DVM, PhD, DACVIM-SAIM, DACVIM-Nutrition, last reviewed November 2023 and last modified June 2025, states:

“Dog foods are generally not satisfactory for cats because some dog foods are lower in protein; often do not contain assured concentrations of taurine; may not contain other essential nutrients required by cats but not dogs, such as preformed vitamin A and arachidonic acid; and may not meet the nutrient requirements for fat, vitamins, and minerals. Many feline diets are also formulated to meet a target urinary pH to lessen the chance of forming crystals.”

Read the hedges rather than editing them out. Generally not satisfactory. Some dog foods. Often do not. May not. That is a reference work describing a category, not a guarantee about the specific bag in your hand. But the list of what can be missing is specific, and every item on it is a nutrient a cat needs and a dog does not need from the diet.

The same author’s article on nutritional requirements of small animals, last reviewed November 2023 and last modified September 2024, states the same asymmetry from the other end:

“Cats have different dietary requirements than dogs and can develop nutritional deficiencies when fed diets formulated for dogs. For example, unlike dogs, cats require dietary sources of vitamin A, arachidonic acid, and taurine. Cats also have higher requirement levels for some amino acids, such as arginine, and the vitamins niacin and pyridoxine (vitamin B6).”

AAFCO says it in consumer language on its “Selecting the Right Pet Food” page, and the sentence is the cleanest statement of the principle we found anywhere:

“Because dogs and cats have different nutrient requirements, pet food must be formulated for the intended species. For example, cats require nutrients, such as taurine and ‘pre-formed’ Vitamin A, that dogs do not.”

One caveat on AAFCO that matters if you go quoting it. AAFCO is not a federal regulator, and its own FAQ shows why: it approves nothing, and its standards acquire force only when states adopt them. Its FAQ page states: “In short, AAFCO does not approve, certify or otherwise endorse pet foods. There is no AAFCO-approved pet food.” And on how its standards acquire force: “Most state feed laws and regulations reference to the AAFCO Official Publication as part of the nutritional adequacy labeling for pet foods.” Model standards, adopted state by state. The nutrient profiles themselves live in AAFCO’s annual Official Publication, which is a paid publication; on the day we checked, AAFCO’s publications page offered the 2026 edition as current and the 2025 edition as the previous year’s. We did not open the profiles table itself, so no number on this page is quoted from it. Where a figure below is attributed to AAFCO, it reaches this page through the Merck Veterinary Manual, which cites AAFCO for it, and we say so.

What Cats Actually Need That Dogs Do Not

The National Academies published a pamphlet, “Your Cat’s Nutritional Needs: A Science-Based Guide For Pet Owners”, which states of itself: “This pamphlet is based on recommendations from the 2006 release of Nutrient Requirements of Dogs and Cats.” It is written for owners, and it names the two amino acids that carry most of the risk.

On arginine: “Arginine, for example, is critical to the removal of ammonia from the body through urine. Without sufficient arginine in the diet, cats may suffer from a toxic buildup of ammonia in the bloodstream.”

On taurine: “Although not the case for dogs, the amino acid taurine is a dietary essential for cats. Taurine deficiency in cats causes a host of metabolic and clinical problems, including feline central retinal degeneration and blindness, deafness, cardiomyopathy and heart failure, inadequate immune response, poor neonatal growth, reproductive failure, and congenital defects. Found abundantly in many fish, birds, and small rodents, taurine is either absent or present only in trace amounts in plants.”

On vitamin A and niacin, the same pamphlet states that cats “must get all of the vitamin A and niacin they need directly from the food they eat.” It then names what a shortfall of either one does: “Deficiencies in vitamin A can adversely affect the health of the eyes. Adult cats deprived of niacin in the diet will lose weight and may die as a result.” Merck explains the vitamin A biochemistry: “cats cannot convert beta-carotene to vitamin A because they lack the intestinal dioxygenase enzyme necessary for beta-carotene cleavage. As a result, cats require a preformed source of vitamin A in their diet, such as that supplied by liver, fish oil, or synthetic vitamin A.”

On arachidonic acid, Merck states: “Cats have an additional requirement for arachidonic acid, another omega-6 fatty acid, which is absent in vegetable oils and fats but found in fat from meat, poultry, and eggs. Unlike dogs, cats cannot readily convert linoleic to arachidonic acid.”

On protein density, Merck gives both the AAFCO and NRC figures side by side: “Diets for adult cats should contain a minimum of 26% protein as dry matter or 65 grams of protein per 1,000 kcal ME (AAFCO guidelines) or 40 g protein/1,000 kcal ME (NRC guidelines)”, against “Adult dogs require a minimum of 18% protein as dry matter or 45 grams per 1,000 kcal ME (AAFCO guidelines).” Those are composition minimums for a formulated food, not amounts to feed anything. They are here to show you the gap, not to be arithmetic you perform at the bowl.

The Direction Nobody Publishes a Deficiency List For

Now the other way round, and this is where an honest page has to say less than the reader wants.

We did not find, in the Merck Veterinary Manual, the National Academies pamphlets, AAFCO’s consumer pages, the FDA’s pet food pages, WSAVA’s guidelines or Cornell’s feline health pages, any statement that a dog eating cat food develops a named nutrient deficiency. The published concern runs the other way. What is published about the composition difference is this, from Merck: “Most commercial adult dog foods typically contain 5%–15% fat (dry-matter basis)”, while “As much as 60% of the calories in a cat’s diet may come from fat, although diets that contain 8%–40% fat (dry-matter basis) have also been fed successfully.” Plus the protein minimums above.

So the risk described for a dog on cat food is a composition mismatch, chiefly on fat and protein density, in a food that was never formulated to the dog’s profile. Merck’s article on pancreatitis, authored by Jörg M. Steiner and last modified September 2025, adds the one line worth carrying: “Dietary indiscretion is believed to be a common risk factor in dogs.” Believed to be, in the source’s own hedge. Note also that Merck’s general framing covers both directions at once, warning that “Dog or cat foods and homemade diets derived from a limited number of food items are often inadequate.”

The honest summary is therefore not “cat food is fine for dogs.” It is that the two directions carry different kinds of risk, that only one of them has a published deficiency list, and that neither one has a published permission slip. If your dog has eaten a large quantity of cat food, or has any history of pancreatitis or any other medical condition, that is a call to your veterinarian rather than a line on a web page.

The Number That Does Not Exist, and What We Searched For It

This is the question every version of this search is really asking. How long? Two days? Two weeks? Give me a ceiling.

We could not find one, and we want to be precise about that rather than vague.

What we searched, on August 11, 2026. The FDA Center for Veterinary Medicine’s pet food pages, including the “Complete and Balanced” Pet Food page, which was marked content current as of 02/28/2020. AAFCO’s consumer pages on selecting pet food, its FAQ, and its publications index. The National Academies’ “Your Cat’s Nutritional Needs” pamphlet based on the 2006 NRC report, read in full from the PDF. The WSAVA Global Nutrition Committee’s “Guidelines on Selecting Pet Foods.” The Merck Veterinary Manual’s articles on nutritional requirements of small animals, on dog and cat foods, and its pet-owner article on proper nutrition for cats. Cornell Feline Health Center’s “Feeding Your Cat” page. Tufts University Cummings School’s Clinical Nutrition Service article on what to do when a pet food is out of stock. And PubMed, queried through the NCBI E-utilities search API for terms covering cats fed dog food and duration, feline taurine depletion time course, and short-term feeding of nutritionally incomplete diets.

What we did not find. No duration, in either direction, from any of those sources. Not a day count for a cat on dog food, not one for a dog on cat food, and not a general ceiling for feeding an animal a food not formulated for its species. That is a statement about what a search of those named sources returned on that date. It is not a claim that no such figure has ever been published anywhere, and if you find one, the test is whether you can open the document it came from and read the sentence in place.

One figure we traced, and what happened to it. A five-to-seven-day limit for homemade meals, attributed to a board-certified veterinary nutritionist at North Carolina State University’s College of Veterinary Medicine, circulates in consumer coverage. We followed it to NC State’s own site. The page there, dated November 3, 2020, is an “In the News” stub: a headline, a byline and a link out to media coverage, carrying no guidance of its own. So we could not verify that figure against anything NC State publishes. We are not saying the number is wrong, and we are not saying the nutritionist did not say it. We are saying we could not trace it to a document a reader can open, which is the standard this site holds itself to, so it is not on this page as a threshold.

What is published, and what it actually measures. Three pieces of peer-reviewed work get quoted in this territory, and all three are easy to misread as countdowns. They are not.

Morris and Rogers, writing in Science in 1978, reported: “Near-adult cats, fasted overnight, and given a single meal of a complete amino acid diet without arginine, developed hyperammonemia and showed clinical symptoms of ammonia toxicity within 2 hours. One cat (2.7 kilograms) died 4.5 hours after ingesting only 8 grams of the diet.” Two hours is arresting, and the fact in the same report that one 2.7-kilogram cat died 4.5 hours after eating just 8 grams of that diet is more arresting still. Both numbers are the reason arginine appears in every discussion of feline nutrition. Neither one is a description of dog food. That experiment used a purified amino acid diet containing no arginine at all. Arginine is not a cat-only nutrient: the Merck Veterinary Manual lists it first among the “Ten amino acids are essential in the diet of dogs”, which is why a dog food formulated to a nutrient profile is not an arginine-free diet. What Merck says about cats and arginine is that they have “higher requirement levels” for it. A higher requirement is a different thing from a total absence, and reading the 1978 result as a two-hour clock on a cat eating dog food would be a serious misuse of it.

Pion and colleagues, in Science in 1987, established the taurine link: low plasma taurine with echocardiographic evidence of myocardial failure was “observed in 21 cats fed commercial cat foods and in 2 of 11 cats fed a purified diet containing marginally low concentrations of taurine for 4 years,” and taurine supplementation “was associated with normalization of left ventricular function in both groups of cats.”

Novotny and colleagues, in the Canadian Journal of Veterinary Research in January 1994, tracked cats on an experimental taurine-deficient diet where “The duration of feeding trials ranged from 6-15 months,” and reported that “The greatest rate of change in M-mode echocardiographic variables occurred during the first four months on the taurine-deficient diet.” They also found the response was not uniform: “No diminution of myocardial function was recorded in a small number of taurine-deficient cats whereas cardiac performance in some taurine-deficient cats diminished to levels characteristic of DCM.”

Put those together carefully. The taurine work runs on a scale of months and years, on purpose-built deficient diets, in a research setting. The arginine work runs on a scale of hours, on a diet engineered to contain none. Those are two different mechanisms on two entirely different timescales, and neither was a study of cats eating commercial dog food. Anyone who blends them into one countdown has manufactured a number that no study supports.

So what do you do with no number? You use the mechanism instead, and you use the phone. The mechanism tells you which nutrients are in question, which is exactly what a veterinarian needs to hear from you: how long it has already been, which product, whether the cat has any signs, and what else is available. That is a conversation with a real answer for your animal. A day count from a stranger on the internet is not.

Reading the Bag You Are Holding

When the choice is between two products you did not plan to use, the nutritional adequacy statement decides more than the brand name does. It is usually in small print on the back or the side.

FDA’s “Complete and Balanced” Pet Food page, content current as of 02/28/2020, explains what the phrase buys you: “If this statement includes the phrase ‘complete and balanced,’ then the product is intended to be fed as a pet’s sole diet and should be nutritionally balanced. Treats, snacks, and supplements are typically not intended to be a pet’s sole diet, so these products are often not complete and balanced.” The same page sets out the two routes to that claim: a food must either “Meet one of the Dog or Cat Food Nutrient Profiles established by the Association of American Feed Control Officials (AAFCO); or Pass a feeding trial using AAFCO procedures.”

The Merck Veterinary Manual explains the sentence you least want to find on a can when the cupboard is otherwise bare. The statement “This product is intended for intermittent or supplemental feeding only” is, in Merck’s words, “required if a product does not meet the requirements for being a complete and balanced diet or any other special nutritional or dietary need and is suitable for only limited or intermittent or supplemental feeding.”

That is where the one quantitative rule we found lands. WSAVA’s Global Nutrition Committee, in a document stamped “Updated on 10 March 2021”, writes that foods “labeled as intended for ‘short-term’, ‘intermittent’, or ‘complementary’ feeding should only be fed as a small portion of the diet (10% or less), or under veterinarian supervision if feeding a therapeutic diet.” Notice what kind of limit that is. It is a proportion of the diet, published by a veterinary body about a labeled class of product. It is not a duration, and it is not a portion size for your animal. It is the reason a stack of pouches labeled that way is not a week of food, however much of it you have.

Four things to read in order when you are standing in an aisle or a garage with two unfamiliar products:

1. Species. Does the label say dog food or cat food? Merck notes that the intended species must appear on the label, and AAFCO’s own instruction is to “select a food labeled for the pet’s species, life stage and condition.”
2. Nutritional adequacy statement. Does it say complete and balanced, or does it say intermittent or supplemental feeding only?
3. Life stage. Growth, gestation and lactation, maintenance, or all life stages. Merck notes that “The term ‘all life stages’ on a label indicates that the product has been either formulated or tested for gestation/lactation, growth, and adult maintenance.”
4. Anything that reads like a medical claim. If the product is a therapeutic diet, you are back in the section at the top of this page, and the decision belongs to the prescriber.

The Never-List, Item by Item, From One Named Source

Every entry below is from the ASPCA Animal Poison Control Center’s page “People Foods to Avoid Feeding Your Pets”, read on August 11, 2026. We are quoting its own categories and its own hedges, not paraphrasing them into something firmer. The page opens with its own instruction: “As always, if you suspect your pet has eaten any of the following foods, please note the amount ingested and contact your veterinarian or poison control at (888) 426-4435.”

Alcohol and yeast dough. ASPCA states that alcohol can cause “vomiting, diarrhea, incoordination, depression, difficulty breathing, tremors, changes in blood pH, coma and even death.” It adds the reason speed matters: “Alcohol is rapidly absorbed after ingestion, so it’s important to take prompt action in seeking veterinary attention if your pet has had exposure.” On dough: “Yeast dough can rise and cause gas to accumulate in your pet’s digestive system. This can be painful and cause the stomach to bloat, and potentially twist, becoming a life-threatening emergency.”

Chocolate, coffee and caffeine. “When ingested by pets, methylxanthines can cause vomiting and diarrhea, panting, excessive thirst and urination, hyperactivity, abnormal heart rhythm, tremors, seizures and even death. The darker (higher cacao percentage) the chocolate, or the higher the caffeine content, the greater the risk for toxicity.”

Grapes and raisins. Here is a place where the source hedges and this page keeps the hedge: “Tartaric acid is speculated to be the toxic component in grapes and raisins. Since dogs are not able to process tartaric acid, exposure to grapes/raisins can lead to kidney damage.” Speculated, in ASPCA’s own word. Treat the mechanism as proposed and the caution as firm.

Onion, garlic and chives. “Allium species can cause gastrointestinal irritation and red blood cell damage, which can lead to anemia (low red blood cells). Although cats are more susceptible, dogs are also at risk depending on the amount ingested.” Pet Poison Helpline’s onion page, read the same day, adds breed detail: “Onion, along with chives, garlic, and leeks, belong to the Allium family; all are poisonous to dogs, cats, and livestock. Certain animal species and breeds are more sensitive to Alliums including cats and Japanese breeds of dogs (e.g., Akita, Shiba Inu).” This is the entry that matters most in a disaster pantry, because Allium ingredients turn up as seasoning in canned soups, stocks, gravies, seasoned meats and many jarred and prepared human foods. The instruction that follows from it is not a rule about a category, it is to read the ingredient list on anything before it goes near an animal.

Macadamia nuts and other nuts. On macadamias: “Macadamia nuts can cause weakness, incoordination, depression, vomiting, tremors and hyperthermia in dogs.” On nuts generally: “Nuts, including almonds, pecans and walnuts, contain high amounts of oils and fats. These fats can cause vomiting and diarrhea, and potentially pancreatitis in some pets.”

Xylitol. “Xylitol can cause low blood sugar (hypoglycemia) and potentially liver damage depending on the amount ingested. Initial signs of toxicosis include vomiting, lethargy and loss of coordination, which can progress to seizures.” ASPCA adds a timeframe and a complication: “Liver damage can occur within 12-24 hours, which can also cause secondary issues with abnormal bleeding.” Xylitol appears in sugar-free products, and ASPCA names gum, candy, baked goods and toothpaste.

Excessively salty foods. “Excessive salt intake can produce increased thirst and urination, and sometimes abnormal electrolytes in the blood depending on the amount ingested. Signs of salt toxicity can include vomiting, diarrhea, depression, tremors, seizures and even death.”

Milk and dairy. “Because pets do not possess significant amounts of lactase (the enzyme that breaks down lactose in milk), milk and other dairy-based products can cause diarrhea or other digestive upset.” So a bowl of milk is not a fallback, and in a shortage a digestive upset is the last thing you want to add.

Raw or undercooked meat, eggs and bones. ASPCA states: “Raw meat and raw eggs can contain bacteria such as Salmonella and E. coli that can be harmful to pets and humans alike. Raw eggs contain an enzyme that can interfere with absorption of certain vitamins, leading to skin/coat problems”, and on bones: “Dogs/cats might sustain injury or obstruction to the gastrointestinal tract when ingesting bones, which could be serious and require surgery.” Merck adds the biochemistry behind the raw-egg warning, describing “avidin found in raw eggs, which destroys biotin”, alongside “thiaminases found in raw fish, which destroy thiamine.”

Avocado, citrus, coconut. ASPCA scopes avocado to birds, rabbits, donkeys, horses and ruminants as above. On citrus it states that the stems, leaves, peels, fruit and seeds “contain varying amounts of citric acid and essential oils that can cause irritation and possibly even depression if ingested in significant quantities”, while “Small ingestions, such as eating the fruit, are not likely to present problems beyond minor stomach upset.” On coconut, small amounts are “not likely to cause serious harm” but the oils “may cause stomach upset, loose stools and diarrhea.” These entries are included precisely because the source hedges them; a never-list that flattens every entry into the same red is a less useful list, not a safer one.

If your pet has already eaten something on this list, the action is a phone call to your veterinarian, an emergency clinic, or an animal poison control service, with the amount noted, rather than watching to see what happens. Two national poison-control lines are the ASPCA Animal Poison Control Center at (888) 426-4435 and Pet Poison Helpline at (855) 764-7661, read from each organization’s own site on August 11, 2026; both are staffed lines that may charge a consultation fee.

Why “I’ll Just Cook Something” Is the Wrong Instinct

This is the reflex that feels most responsible and is least supported by the sources.

The Merck Veterinary Manual’s article on nutritional requirements of small animals states: “Dog or cat foods and homemade diets derived from a limited number of food items are often inadequate. For example, feeding predominantly meat or even an exclusive hamburger and rice diet to dogs or cats can induce calcium deficiency and secondary nutritional hyperparathyroidism. Feeding only liver can induce vitamin A toxicity in both dogs and cats.”

That single passage takes out the two most common improvised menus at once. Meat and rice, the thing everyone reaches for, is named. Liver, the thing people reach for because it seems nutrient-dense, is named as a toxicity route rather than a fix. Merck’s article on dog and cat foods adds that “It is most difficult to formulate a nutritionally complete and balanced diet with sufficient nutrient density in a small volume of food that is palatable for cats”, and states that owners who choose a home-cooked diet “should use a recipe formulated by a boarded veterinary nutritionist (versus a recipe found on the internet or in a book).”

Tufts’ Clinical Nutrition Service says the same in owner-facing language: do not cook your pet’s food unless you have considered the trade-offs, are “willing to work with a Board Certified Veterinary Nutritionist to get a nutritionally balanced recipe”, and are willing to follow that recipe exactly.

So this page publishes no recipe, no portion, no feeding frequency and no supplement amount, including for taurine. Not because the information is secret, but because getting it right for a specific animal is a veterinary act, and getting it wrong is how the deficiencies above happen. The site’s standing position applies here in full: we are not veterinarians, and the decision on what goes in the bowl belongs to one.

The Order of Operations When You Actually Run Out

Every step below is a routing step. None of them is a substitution instruction, and the sequence is drawn from the Tufts Clinical Nutrition Service article, which is the only owner-facing piece from a veterinary school’s nutrition service we found that addresses this exact situation.

1. Exhaust the same product first. Tufts: “For dry food, it may just be a single bag size that is out of stock and a larger or smaller bag may still be available.” A different bag size of the identical product is not a diet change at all.

2. Then the same product, different flavor, but check who your animal is. Tufts: “For healthy pets, a different flavor or for dogs, a different dog size (e.g., small breed vs. large breed) of the same product is usually a good alternative option. For pets with medical issues, check first because different flavors or dog size of the same product can have very different nutritional profiles.” Note the two halves of that sentence and which one applies to you.

3. Call the manufacturer. Tufts: “Check online for availability through multiple websites of both large and small retailers or contact the manufacturer for information. The manufacturer can sometimes direct you to a retailer or veterinarian that has the food in stock.” The consumer line on the bag is a real resource, and it is the same line WSAVA tells owners to expect a company to staff, noting that “Company representatives should be easily accessible for additional questions, such as the level of specific nutrients not on the label.”

4. Call your veterinary clinic, and describe the actual situation. Tufts: “Talk to your veterinarian for recommendations on an alternate diet that will meet your pet’s specific needs. This is especially important if your pet has medical issues.” In a disaster, add the operational facts: whether you are displaced, how long you expect to be, and what you can actually get to. That changes the answer.

5. Ask about local pet food assistance. Many humane societies and animal welfare organizations run pet food pantries, and in a declared emergency, animal response groups often distribute food. This is a real supply route rather than a substitution, and it is worth asking your clinic, your shelter or your county animal services about by name.

6. Only then, with a veterinarian on the phone, talk about a substitution. By this point the conversation is specific: this animal, this condition, this product, this many days, these options.

A note on transitions, since it is the step people skip when they are rushing. Tufts: “Some pets can switch from one diet to another ‘cold turkey’ with no transition without any problems. Others, however, need a much more gradual transition over 7-10 days.” That is a description of two kinds of animal, not a schedule for yours, and the article’s own point is that the cushion of food is what buys you the option to go slowly. Which brings us to the part you can do before any of this happens.

The Reserve That Stops This Page From Being Needed

The version of this problem that actually bites a multi-species household is not “we ran out of food.” It is “we ran out of one animal’s food,” which is a different failure and has a different fix.

It happens because reserves get sized in household days. You buy a big bag and a stack of cans, you think of it as the pet food shelf, and the shelf runs down unevenly because the animals eat different amounts of different products at different rates. The cat food goes first, or the special bag for the older dog goes first, and now you are holding a substitution question you never intended to ask.

Three habits fix it, and none of them requires a number from us.

Count the reserve per animal, not per household. Each animal’s food is its own countdown. A shelf that holds a fortnight for one animal and four days for another holds four days, because the day the short one runs out is the day this page becomes relevant. Our long-term pet food and water storage page is where the published day-count standards live, with the disagreements between the agencies laid out, and our emergency food and water storage guide covers the containers and the water side.

Rotate against the constraint animal. The animal with the least flexible diet sets the schedule for the whole household. Tufts frames the same idea from the veterinarian’s side, describing one of her own dogs, whose medical issues make his requirements very specific and his options few, as the one she keeps the bigger cushion for. Our pet emergency kit rotation checklist is the recurring version of that job, and when to buy pet emergency supplies before hurricane season sets the calendar.

Decide the back-up before you need it, and write it down. This is Tufts’ central recommendation and it is the one that removes the emergency entirely: “Talk to your veterinarian about a good back-up food for your pet that has a similar nutritional profile to the diet you’re feeding (or, if your pet’s medical and nutritional needs are complex, you can consider working with a Board Certified Veterinary Nutritionist).” She adds the reason for doing it early: “it’s good to think about it ahead of time, rather than in a panicked scramble as your pet is finishing the last few bites from a bag or can.” For a multi-species household that means one named back-up per animal, agreed with your clinic, written in the same place you keep the vaccination records. Our pet emergency binder is where that line goes, and multi-pet emergency planning works the rest of the household-level arithmetic, with multi-pet go-bag math handling what you carry rather than what you keep.

If you have not yet chosen the formats that make up that reserve, that decision has its own page: freeze-dried versus canned versus kibble for emergency storage compares them on shelf life, weight, water dependency and heat tolerance. This page is what happens after that stock is gone or out of reach; that page is how you build it so it is not.

Your Ran-Out Checklist

• Confirm first whether your animal is on a therapeutic or prescription diet. If yes, stop and call the prescribing veterinarian before substituting anything.
• Same for a puppy, kitten, pregnant or nursing animal, a diabetic on fixed insulin timing, or an animal with a diagnosed food allergy. Each one is a phone call, not a judgment call.
• If your animal is not a dog or a cat, none of this page applies. Call a veterinarian who treats that species.
• Check whether the identical product exists in another bag size or another flavor before you consider a different food at all.
• Call the manufacturer’s consumer line on the bag. They can sometimes route you to stock you cannot see online.
• Call your veterinary clinic with the specifics: which animal, which product, how long, any signs, and what you can actually reach.
• Ask your clinic, local shelter or county animal services whether a pet food pantry or a disaster food distribution is operating.
• Read the nutritional adequacy statement on anything you are considering. Complete and balanced is a different product from one labeled for intermittent or supplemental feeding only.
• Read the ingredient list on any human food before it goes near an animal, because onion and garlic are ordinary seasonings and both are on the ASPCA’s list.
• Do not improvise a cooked diet, a recipe or a supplement, including taurine. That belongs to a veterinarian or a board-certified veterinary nutritionist.
• Watch for vomiting, diarrhea, refusal to eat, lethargy, weakness or a painful abdomen after any diet change, and call rather than wait.
• Afterwards, when it is calm: choose a named back-up food per animal with your veterinarian and write it in your records, and re-size the reserve per animal rather than per household.

Where to Go Next

This page sits in our pet evacuation kits pillar, and it is the one you read when the plan has already failed. The rest of the food and water problem splits three ways.

Building the stock. Freeze-dried versus canned versus kibble picks the formats, long-term pet food and water storage sets the shelter-in-place standard against the published agency figures, and the pet emergency kit rotation checklist keeps it from quietly expiring.

The water half. Food is the half of this that tolerates a shortfall least badly. How much water per dog in an emergency and water purification for pets cover the other half, and they are not a place to improvise either.

The household. Multi-pet emergency planning covers the grab order, supply arithmetic and per-animal documents, multi-pet go-bag math covers what leaves the house with you, and returning home with pets after a disaster covers what to check when you get back to whatever is left in the cupboard.

Then do the one thing that makes this page unnecessary. Ask your veterinarian, on an ordinary day, what the back-up food is for each animal in your house. Write the answer down. The whole reason this question is dangerous is that it usually gets asked at the worst possible moment by someone who has never asked it before.