Meat or vegan? Scientists decide which diet is better for the all-around health of dogs

Dog owners are increasingly asking whether their pets can thrive without meat. A new analysis offers a nuanced answer: plant-based dry foods sold in the UK can deliver nutrition comparable to meat-based products.

However, most products of all kinds, including veterinary renal diets, fall short of industry nutrient guidelines. 

The study, led by the University of Nottingham, included laboratory testing of thirty-one dry foods labeled “complete,” a term that signals a product should provide all essential macro- and micronutrients for an adult dog.

The research team examined 19 meat-based diets, six plant-based diets and six veterinary formulations designed to be lower in protein for dogs with kidney disease.

The team measured total protein, essential amino acids, fatty acids, vitamin D, all B-vitamins, and major and trace minerals, then compared those values with European Pet Food Industry Federation (FEDIAF) recommendations for adult maintenance.

Nutrition from different dog diets

Perhaps the most striking result is how closely plant-based and meat-based diets aligned for total protein and most essential amino acids. 

The big differences emerged elsewhere. On average, vegan formulas provided less iodine and fewer B-vitamins than meat-based diets – shortfalls that echo what nutritionists often see in human plant-forward eating. 

Crucially, these are straightforward formulation problems to solve. Iodine fortification and robust, bioavailable B-vitamin premixes can close the gap without changing the overall dietary philosophy.

According to study lead author Rebecca Brociek, while many people assume dogs “need meat” to stay healthy, biologically they just need nutrients in the right amounts and forms.

Thus, plant-based products “stacked up more closely to meat-based diets than expected,” even as both categories revealed some nutritional gaps.

Similar studies in Brazil and Canada point in the same direction: properly formulated vegan diets can be a viable option for adult dogs.

The “complete” label falls short

While every food in the study met the guideline for vitamin D, very few met all targets at once. Just over half complied with essential amino-acid recommendations, fewer than one in five hit all mineral targets, and only a handful satisfied every B-vitamin requirement.

In practical terms, 30 of the 31 products were missing at least one essential nutrient for adult maintenance.

This does not mean a single bowlful is dangerous. Shortfalls accumulate over time. If iodine remains low, for example, the thyroid can struggle; if B-vitamin levels are chronically inadequate, energy metabolism and nerve function may be affected. 

The takeaway for manufacturers is clear: publish full nutrient profiles, test routinely, and fortify thoughtfully. For dog owners, it is a reminder to look beyond marketing claims and, when possible, ask brands for detailed analyses.

Medical diets and dog nutrition

The veterinary renal diets in the sample illustrate a different kind of trade-off. These foods intentionally lower crude protein to reduce kidney workload, a valid clinical strategy.

But the study found that two-thirds of these low-protein products also fell short on one or more essential amino acids. 

That is not an indictment of renal nutrition; it is a formulation challenge. Even at reduced total protein, companies can blend higher-quality protein sources or add specific amino acids – lysine, methionine, tryptophan, and others – to maintain adequacy while meeting therapeutic goals.

For dogs managing kidney disease, veterinarians remain the best guides; the solution here is better amino-acid balancing, not abandoning medical diets.

What this means for everyday feeding

For healthy adult dogs, the findings open space rather than close doors. A well-designed plant-based diet can be nutritionally adequate, provided it is properly fortified with iodine and a complete B-vitamin spectrum and meets amino acid and mineral targets. 

Meat-based diets are not automatically superior; they must meet the same benchmarks. Labels that claim “complete” should be supported by transparent data, and pet owners can reasonably expect brands to share that information.

Every dog is an individual. Age, activity level, body condition, pre-existing conditions, and even gut health can shift needs and influence how well a dog absorbs and uses nutrients.

That is why regular veterinary checkups – ideally with periodic bloodwork for dogs on unconventional or therapeutic diets – remain the gold standard for catching problems early.

Limitations of the study

This research analysed nutrients in the lab; it did not follow dogs over months or years to track clinical outcomes. The study also focused on adult-maintenance foods rather than puppy diets, where requirements are higher and the margin for error is smaller.

And while hitting a target on paper is essential, bioavailability can vary with ingredient sources, processing methods and the health of a dog’s digestive tract. 

The authors call for long-term feeding trials and bioavailability studies, especially for plant-based and renal formulations, to connect lab values with real-world health markers.

These markers include body condition, muscle maintenance, thyroid and kidney function, skin and coat quality, and immune status.

Achieving complete nutrition for dogs

The encouraging part is how fixable the shortfalls appear. Fortifying vegan recipes with iodine and comprehensive B-vitamin premixes, tightening amino-acid balance in low-protein therapeutic diets, and publishing batch-tested nutrient profiles would close most of the gaps identified. 

For environmentally minded owners curious about lower-impact options, that matters. For veterinarians and formulators, it is a roadmap: engineer for nutrients, not narratives; verify with data rather than assumptions.

Brociek’s own conclusion captures the pragmatic spirit of the work. Plant-based diets, when properly formulated, can be a healthy and viable alternative to meat-based options. 

The next step should be long-term feeding studies. In the meantime, the message to the industry is straightforward. Whether the protein comes from chicken or chickpeas, the job is the same: deliver complete, bioavailable nutrition, prove it with transparent testing, and give owners the information they need to feed confidently.

The study is published in the journal PLOS One. 

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