Plant-based diets for dogs have come under fresh scrutiny, and a new review by Andrew Knight in the journal Animals continues to add even more impressive evidence to the conversation. The study looked at 29 scientific papers on plant-based diets and ingredients in dogs, focusing on how well these foods are digested and how well dogs can use the nutrients.
The headline takeaway is clear: when properly formulated, plant-based diets are highly digestible and broadly comparable to conventional meat-based diets.
What digestibility actually means
In nutrition, “digestibility” is a simple concept with a big impact. It describes how much of the food a dog eats is actually absorbed and used by the body, rather than passing through and appearing in the stool.
High digestibility means:
- More of the nutrients are absorbed
- Less is wasted in the faeces
The dog gets more usable energy and building blocks from the same amount of food
Low digestibility, by contrast, can mean more stool, less efficient nutrition and the need for higher inclusion levels to meet the same nutritional needs.
In practice, digestibility is one of the key markers of whether a diet is truly “fit for purpose”.
What the review found for plant-based diets
Knight’s review examined 29 studies that looked at plant-based diets and ingredients in dogs, including work on digestibility of whole diets and individual ingredients.
Across these studies:
- Plant-based diets were consistently well digested by dogs
- Digestibility values were broadly similar to those seen with conventional meat-based diets
- Individual vegan protein sources, including legumes, pulses, grains and microbial proteins, were also well digested
This challenges the common claim that plant-based diets are inherently poorly digested or unsuitable for dogs. The evidence shows that, when properly formulated, they can be just as effective.
The 80% benchmark: apparent total tract digestibility
A key part of the review focused on “apparent total tract digestibility” (ATTD), which is a standard way of measuring how much of a diet is absorbed across the entire digestive system.
In all five studies that assessed ATTD for plant-based pet diets, the values exceeded 80% for dry matter, and were also high for organic matter, crude protein, fat and energy.
To put that in context:
- Values above 80% are generally considered good for canine diets.
- These results show that plant-based diets can meet that benchmark consistently.
- The data support the idea that plant-based diets are not only acceptable, but genuinely well adapted for dogs when properly formulated.
Why this matters
For dog owners, digestibility is not an abstract concept. It affects:
- How well the dog thrives on the food
- Stool quality and volume
- How efficiently the diet supports energy, growth and maintenance
If a diet is poorly digested, a dog may need to eat more to get the same nutritional benefit, and owners may see looser stools. If a diet is well digested, the dog can meet its needs from a smaller, more efficient ration, often with better stool quality.
The new review shows that plant-based diets can deliver that high level of digestibility, which is a strong vote of confidence in their nutritional soundness.
Why Omni believes this matters
At Omni, we believe dog owners deserve access to science-backed, well-formulated diets that support their dog’s health without unnecessary risk or compromise. This review is another strong piece of evidence that plant-based and novel-protein diets can be highly digestible and nutritionally sound when done properly.
It also supports our approach: focusing on complete, balanced diets, grounded in evidence, and designed to support allergy-prone and sensitive dogs in a practical, everyday way.
Take Home Message
The review by Andrew Knight, covering 29 studies on plant-based diets and ingredients in dogs, shows that:
- Plant-based diets are well digested by dogs
- Digestibility values consistently exceed the 80% benchmark for apparent total tract digestibility
- These diets are broadly comparable to conventional meat-based options in terms of how efficiently dogs can use them
This is yet another substantial body of evidence demonstrating the validity of plant-based foods for dogs. For dog owners, the message is clear: the science is catching up with the options already on the shelf.
