This blog post has been a long-time coming.

Since 2019, dog guardians have been warned to fear one ingredient above all others: legumes.

We’ve been told they’re dangerous.
That they cause heart disease.
That they represent a nutritional experiment gone wrong.

And yet, one essential question remains largely unanswered:

What about the food dogs have been eating all along?

A Convenient Villain

The narrative around diet-associated DCM (Dilated Cardiomyopathy) focused almost entirely on what was new. Legumes, boutique brands, grain-free labels. Not on what was normal. 

Based on industry reaction, this narrative was started to increase market share for a player in BIG Pet. 

But dogs did not suddenly develop complex chronic disease because peas appeared in their bowls.

What is rarely acknowledged is this:

After years of investigation, the U.S. Food and Drug Administration did not establish a causal link between legumes and dilated cardiomyopathy. In its final public updates, the FDA acknowledged that the data was inconsistent, incomplete, and confounded by multiple variables. No definitive dietary cause was identified, and the agency ultimately stopped issuing updates.

This was not a confirmation of guilt. It was an admission of uncertainty.

Yet, by the time the investigation quietly ended, the damage had already been done.

Fear-based messaging had spread faster than the evidence, entire categories of food were publicly vilified, and consumers were left with the impression that the science was settled when it was not. The controversy even resulted in class action lawsuits alleging that misleading claims made during the DCM scare caused consumer and market harm.

When a single ingredient becomes the villain, it conveniently diverts attention away from far more uncomfortable questions. Questions about processing, byproducts, rendering, and the long-term health consequences of ultra-processed, extruded pet foods. (Yeah, but what about 'raw'? I'll get to that in another post.)

Questions the industry has still not meaningfully answered.

What Is Actually in Conventional Meat-Based Kibble?

Most conventional pet foods rely on:

• Rendered animal byproducts

• Slaughterhouse waste streams

• High-temperature extrusion

• Synthetic nutrient re-addition to replace what processing destroys
  

Rendering does not start with fresh meat. It starts with what humans will not eat. Tissues that are heat-treated, dehydrated, ground, and stabilized to survive months or years on shelves.

Extrusion then subjects these ingredients to extreme heat and pressure. This process fundamentally alters proteins and fats in ways that are rarely discussed.

What Extrusion Does to Animal-Based Ingredients

High-heat extrusion does more than shape kibble.

It denatures proteins, changing their structure in ways that can reduce digestibility and alter how the immune system recognizes them.

It oxidizes fats, particularly animal fats, creating lipid peroxides and inflammatory byproducts linked to cellular damage.

It produces advanced glycation end products (AGEs), compounds formed when proteins and fats react with sugars under heat. AGEs are well-studied in human nutrition and are associated with inflammation, oxidative stress, and chronic disease.

It also contributes to an acidic metabolic load, increasing the risk of low-grade metabolic acidosis. Chronic acidosis places stress on organs, bones, and cardiovascular systems, particularly in aging bodies.

These effects are not theoretical. They are established outcomes of high-heat processing.

And yet, they are almost never part of the conversation around canine health.

Processing Matters in Humans and Dogs

In human nutrition, ultra-processed foods are now openly associated with:

• Chronic inflammation

• Metabolic dysfunction

• Gut microbiome disruption

• Increased disease risk

But when it comes to dogs, the message has been simple:

“It’s complete and balanced, therefore it’s safe.”

That is not the same as optimal. And it is not the same as preventative.

Where Is the Same Scrutiny?

If legumes were truly the root cause of canine heart disease, we would expect:

• Consistent causation across populations

• Clear, reproducible mechanisms

• Resolution simply by removing them

That has not happened. Legumes have been in pet diets for decades.

What has happened is a near-total lack of investigation into:

• Long-term feeding of extruded diets

• Cumulative toxin exposure from rendered animal ingredients

• Chronic inflammation driven by oxidized fats and AGEs

• The role of metabolic acidosis in long-term canine health

Instead, fear has been focused outward, away from the dominant industry model.

Following the Money Is Not Cynicism

The pet food industry is not nutritionally neutral.

It is deeply intertwined with:

• Veterinary education

• Sponsored research
  

• Prescription diet marketing

• Outdated clinical feeding recommendations

• Corporate ownership of clinics and their own line of pet foods

When the same system that profits from ultra-processed foods also frames the nutritional narrative, it is fair and necessary to ask:

Whose interests are being protected?

That question is not anti-science. It is context.

Dogs Deserve Better Than Fear Campaigns

Dogs are living longer due to advanced medical options, yet experiencing more chronic disease than ever.

Skin disorders.
Digestive dysfunction.
Autoimmune disease.
Cancer.
Heart disease.

Blaming a single plant ingredient does not explain this reality.

But questioning processing, ingredient sourcing, and industry incentives just might.

The Real Question

Instead of asking, “What new ingredient should we fear?”

Maybe it is time to ask:

What have we been feeding dogs for decades, and why has it gone unquestioned?

Because progress in nutrition does not come from protecting the status quo.

It comes from truth, transparency, and the courage to challenge powerful systems, especially when farmed animals, your companion and your bank account are the ones paying the price.

Got questions? I'm all ears. Let's keep asking the right questions from a place of truth, not decades of marketing spin and share value for a corporation's deep pockets.

"The diseases we are treating is the food we are feeding." 

- Bill Pollak, DVM, Fairfield, Iowa

ABOUT THE WRITER:

Laura Simonson is the founder of Virchew, Canada’s first woman-owned, plant-based dog nutrition company. With over 35 years of experience in canine nutrition, she works tirelessly to challenge fear-based narratives and industry-protected myths. Because truth should never be controversial.