The Canine Ledger

Why Most Homemade Dog Food Isn't Complete: And What the Studies Actually Found

Written by thecanineledger

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If you have looked into cooking for your dog, you have met a statistic. Usually it is “94% of homemade dog diets are nutritionally incomplete,” sometimes “95% of recipes are missing an essential nutrient,” occasionally both in the same paragraph as though they were the same finding.

They are not the same finding. They come from different studies, a decade apart, using different methods, measuring different things, and one of those numbers does not appear in the paper it is attributed to.

We went and read them. Here is what they actually say, why the real picture is more useful than the headline, and what it means if you are cooking for your dog.

1. The 2013 study: 200 recipes, on paper

Stockman J, Fascetti AJ, Kass PH, Larsen JA. “Evaluation of recipes of home-prepared maintenance diets for dogs.” JAVMA 2013;242(11):1500–1505.

Researchers at UC Davis collected 200 recipes from 34 sources (veterinary textbooks, lay pet-care books, and websites) and analysed each against both the National Research Council’s requirements and the AAFCO nutrient profiles.

The headline result, verbatim:

“Overall, most (190/200 [95%]) recipes resulted in at least 1 essential nutrient at concentrations that did not meet NRC or AAFCO guidelines.”

The deficiency breakdown, also verbatim:

“The most commonly deficient nutrients, when compared with the NRC MR or NRC RA, were zinc (138 [69%] recipes), choline (129 [64.5%] recipes), copper (108 [54%] recipes), the combination of EPA plus DHA (107 [53.5%] recipes), and calcium (70 [35%] recipes).”

And the finding people find hardest to believe:

“Only 3 recipes provided all essential nutrients in concentrations meeting or exceeding the NRC RA, and another 2 recipes provided all essential nutrients in concentrations meeting or exceeding the NRC MR; all 5 of these recipes were written by veterinarians.”

Five out of two hundred.

Did the author’s qualifications matter? Yes, and with a nuance worth having. Of the 200 recipes, 129 were written by veterinarians and 71 by non-veterinarians. Recipes by veterinarians were significantly better (P = 0.001), and still almost entirely inadequate, since only 5 of those 129 met a standard. Separately, the four recipes in the sample written by board-certified veterinary nutritionists all had acceptable profiles. That is four recipes; treat it as a striking observation, not a powered comparison.

One more finding that explains a great deal:

“Most (184 [92%]) recipes contained vague or incomplete instructions that necessitated 1 or more assumptions for the ingredients, method of preparation, or supplement-type products.”

Ninety-two percent of published recipes were not specific enough to analyse without the researchers guessing.

What this study did not do. It analysed recipes on paper using nutritional software. No food was cooked, no food was assayed, and no dog was fed or examined. It measures the quality of published recipes, not the health of dogs eating them. And the recipes were a convenience sample of what is published, not a sample of what owners actually feed.

Lead investigator Jennifer Larsen summarised it: “Most available recipes for healthy dogs, even those published in books by veterinarians, do not provide essential nutrients in the quantities required by the dog.”

Our note: A formal correction to this paper exists (JAVMA 2014;245(2):177), and we couldn’t retrieve what it corrected. Our quotes come from an author-deposited copy of the full text.

2. The 2025 study: 1,726 real diets: and the number that isn’t in it

O’Brien JS, Lawson E, Dog Aging Project Consortium, Tolbert MK, Ruple A. “Findings from the Dog Aging Project: home-prepared diets for companion dogs feature diverse ingredients, and few are nutritionally complete.” AJVR 2025;86(11).

This one looked at what owners actually feed. Researchers took free-text diet descriptions from 1,726 dogs in the Dog Aging Project cohort and had trained coders enter the ingredients into a recipe tool built by veterinary nutritionists, scored against the AAFCO adult maintenance profile.

The finding, verbatim from the abstract:

“Only 6% of these diets were potentially nutritionally complete according to the Association of American Feed Control Officials adult dog maintenance standards.”

Now: the number you have seen is 94%. That number is not in the paper. It is 100 minus 6, computed by whoever wrote the first headline, and it has been repeated ever since, including, we should note, in reputable trade press.

Why the distinction matters, in four parts:

“Potentially” is doing real work. The study says potentially complete, not complete.

There were no ingredient quantities. Coders had ingredient lists. Lead author Janice O’Brien said so plainly: “Since our study didn’t include exact ingredient amounts, it’s possible that a smaller percentage than 6% were nutritionally complete.” So this is a best-case screen: a diet could pass on its ingredient list and still fail on amounts. The true figure is probably worse, not better.

Nothing was analysed in a laboratory, no dog was examined, and no health outcome was measured. This study does not show that 94% of dogs eating home-prepared food are unwell. It shows that few such diets look complete on paper.

Forty-five percent of these “home-prepared” diets included commercial food or a base/topper. So a substantial share of the sample were not fully home-formulated diets at all, which is worth knowing before you generalise the result to someone cooking from scratch.

So why are we telling you this? Because the honest version is still damning, and because a site that inflates a statistic in its own favour has no business criticising anyone else’s sourcing. Six percent potentially complete, on the most generous possible reading, is a serious finding. It does not need help.

Our note: One secondary write-up reports that “roughly 25% of diets were partially balanced, while 52% had 10+ nutrient imbalances.” Those figures are not in the abstract, and we couldn’t check the full text.

3. And a third, in a different language

Less quoted, and useful because it used a different standard entirely.

Pedrinelli V, Gomes MOS, Carciofi AC. “Analysis of recipes of home-prepared diets for dogs and cats published in Portuguese.” Journal of Nutritional Science 2017;6:e33.

106 recipes scored against the European FEDIAF standard rather than AAFCO or NRC. The finding: “All diets had at least one nutrient below the recommendations, and all investigated nutrients were deficient in at least one diet.”

For dog recipes specifically: vitamin E below recommendation in 82.9%, zinc in 75.6%, calcium in 73.2%, iron in 68.3%. Beyond the nutrients: 48% gave no precise quantities, 53.7% included no vitamin-mineral supplement, 71.3% did not say how much to feed, and 10.2% contained potentially toxic ingredients: onion or garlic.

Different country, different language, different standard, same result.

A note on citation hygiene: this paper is widely mis-attributed to PLoS ONE. It is in the Journal of Nutritional Science, and it is open access.

4. What actually goes wrong

The studies agree on which nutrients fail, and each failure has an ordinary kitchen explanation.

Zinc: deficient in 69% of recipes, the single commonest gap. Zinc is poorly absorbed to begin with, and it is actively antagonised by phytate (in grains and legumes) and by excess calcium. So a diet with added calcium plus rice can be zinc-deficient even when the raw zinc content looks fine. Deficiency shows up as crusting and hair loss around the muzzle, eyes and pressure points.

Choline: 64.5%. AAFCO requires 1,360 mg/kg of dry matter. Egg yolk and liver are the practical sources; chicken breast and rice supply very little, and choline is simply not in most people’s mental model of “add a multivitamin.”

Copper: 54%. Concentrated in organ meat, especially liver. A diet with no liver and no supplement is typically short. (Worth separating from a different debate: copper is a deficiency risk in homemade food and an excess controversy in commercial food. Do not merge the two.)

EPA and DHA: 53.5%. Trimmed lean meat and boiled rice carry very little fat of any kind. Cooking “healthy” by stripping fat removes the nutrient class that carries essential fatty acids and the fat-soluble vitamins with them.

Calcium: 35%, and the one with published case evidence behind it. Muscle meat is high in phosphorus and very low in calcium. A meat-and-rice diet with no bone, bone meal or calcium salt has an inverted calcium:phosphorus ratio, and the body responds by stripping calcium out of the skeleton to hold blood levels normal: nutritional secondary hyperparathyroidism, historically called “all-meat syndrome.”

That is not theoretical. A 2024 case series described four large-breed puppies fed exclusively on unsupplemented boneless raw meat, presenting with pain and hindlimb weakness. Imaging showed reduced skeletal density in all four. Two had fractures and were euthanised. The two survivors recovered on pain relief and a commercially formulated balanced diet (Nowak et al., Animals 2024;14(12):1783).

→ The Calcium Problem: Why Meat-and-Rice Diets Break Bones

Vitamin D and iodine round out the list. Dogs cannot make meaningful vitamin D in skin from sunlight: it has to come from food, from a short list of sources. Iodine occurs in almost no ordinary foodstuff at useful density except iodised salt, dairy and seaweed; one German study of 95 raw rations found “about half of the rations supplied less iodine than the minimum requirement” (Dillitzer et al., British Journal of Nutrition 2011).

5. Two things that don’t fix it

Adding a multivitamin. This is the intuitive fix and it does not work reliably. A 2021 study of 100 recipes concluded, verbatim: “The presence of supplement on its own does not ensure a balanced diet for dogs and cats.” A third of dog recipes contained no supplement at all, and zinc remained deficient in supplemented and unsupplemented recipes alike (BMC Veterinary Research 2021;17:358).

A human multivitamin is formulated for a human’s requirements in a human’s diet. It is not a patch for a specific set of gaps in a specific recipe.

→ Why Adding a Multivitamin Doesn’t Fix an Unbalanced Recipe

Getting a good recipe and then following it. This one is uncomfortable, and it is the most under-reported finding in the whole subject.

Researchers surveyed owners who had been given a home-cooked recipe by a veterinary nutrition service. About a year later, 81% were still feeding home-cooked food. But of those, only four owners, 13%, were following the recipe exactly (Johnson et al., Journal of Small Animal Practice 2016;57(1):23–27).

Be careful with that number: 13% is four dogs out of a small sample from one specialty referral practice. It is not a population statistic. But the direction is corroborated elsewhere: in a study of prescribed elimination diet trials, only 40.1% of 192 owners reported full adherence (Painter et al., JAVMA 2019).

And substitutions are not small. A board-certified nutritionist’s worked examples: baking potatoes instead of boiling them yields about 20% more potassium; swapping in sweet potatoes adds roughly 60% more calories (Tufts Petfoodology). Recipes drift because cooking drifts: a different oil, no salt, a handful of kelp, a bit more meat because he liked it.

→ How to Follow a Recipe Exactly, and Why Substitutions Aren’t Small

6. What “complete and balanced” actually means

Worth knowing, because the phrase is doing more work than most people realise, and less.

AAFCO does not approve pet food. In its own words: “AAFCO does not regulate, test, approve or certify pet food.” It publishes model nutrient profiles that states may adopt into law (AAFCO). “AAFCO approved” on a package is a marketing phrase with no meaning.

A commercial label can claim complete and balanced by one of two routes: formulation (“formulated to meet the nutritional levels established by the AAFCO Dog Food Nutrient Profiles”), a calculation showing the nutrient concentrations hit the profile; or a feeding trial (“animal feeding tests using AAFCO procedures substantiate…”), a protocol run in live dogs. The second is a higher bar for whether nutrients are actually absorbed, and it is rare: in one study of 39 commercial diets, only 2 had passed feeding trials while 35 were formulated-to-meet.

And for a diet you cook at home, none of this applies at all. There is no label, no adequacy statement, no ingredient standard, and no inspection. Nobody is checking. That is not a scandal, it is your kitchen, but it does mean the entire quality-control apparatus that sits behind commercial food is absent, and something has to replace it.

→ “Complete and Balanced”: What It Means, and What an AAFCO Statement Actually Certifies

7. What this does and does not mean for you

If you have been cooking for your dog, the above is a lot to take. So, precisely:

It does not mean your dog is ill. None of these studies examined a dog. They evaluated recipes and ingredient lists. Deficiency takes time to produce clinical disease, adult dogs have reserves, and many home-fed dogs are visibly thriving.

It does not mean homemade food is worse than commercial food. That is a different question, and these studies do not answer it. The most encouraging clinical data on home feeding is a 2024 case series of 167 dogs on customised homemade diets, in which owners reported coat and digestive improvements (Pignataro et al., Veterinary Sciences 2024;11(9):438), though it had no control group, no randomisation, no nutrient analysis of what was fed, and 38% discontinued. Treat it as encouraging, not as proof.

It does not mean you should stop. For some dogs (certain gastrointestinal cases, ultra-low-fat requirements with no commercial equivalent) a properly formulated home diet is genuinely the best option available.

What it does mean is that the recipe you found online is very unlikely to be complete, that a multivitamin will not have fixed it, that the gaps are in nutrients you have probably never thought about, and that puppies have far less margin for error than adults.

And that this is fixable. A formulated recipe is available, and it is the entire point of the next article.

→ How to Get a Properly Formulated Recipe (and What It Costs)

If you want one thing to do today: have the calcium conversation with your veterinarian. It is the failure with the clearest evidence of harm, and it is the easiest to get wrong.

Our note: We don’t want to shame owners who have already committed to home cooking. Talking to your vet about calcium is a good first step.

8. What we could not verify

Commonly saidWhat we found
“94% of homemade diets lack complete nutrition (Dog Aging Project)”Not in the paper. The paper says 6% were potentially complete. 94% is a media derivation, and the study had no ingredient quantities, no lab analysis, and 45% of diets included commercial food.
“95% of homemade recipes are dangerous”The 2013 study found 95% had at least one nutrient below guidelines. “Below guidelines” is not “dangerous.” Guidelines carry safety margins, and no dog in that study was examined.
“Homemade food is healthier than kibble”No study we found supports this. The best pro-homemade data is an uncontrolled case series of owner-reported outcomes.
“A multivitamin makes it balanced”Contradicted: “the presence of supplement on its own does not ensure a balanced diet.”
“AAFCO approved”Meaningless. AAFCO “does not regulate, test, approve or certify pet food.”
Independent evidence that any commercial balancing premix produces complete dietsWe could not find any. No peer-reviewed study demonstrates that recipes built with a named premix are complete on laboratory assay. See the next article.

Our note: We searched and found no study for the last row, but that doesn’t prove none exists. Our summary of the AAFCO, NRC and FEDIAF standards is simplified.

Sources

The recipe-evaluation studies

Supplements, adherence and outcomes

Harm evidence

Standards and practical guidance

Always confirm with your vet before acting on anything on this page.