• Why Plant-Based?
    • Overview
    • Sustainability
    • Better health
    • Compassion for animals
  • Resources
    • Virtual speaker series
    • Speakers program
    • Pamphlets
    • Newsletters
  • Blog
  • About Us
    • Who we are
    • Contact us
  • How to Help
    • Join us
    • Donate
  • Subscribe to Newsletter
Earthsave CanadaEarthsave Canada
  • Why Plant-Based?
    • Overview
    • Sustainability
    • Better health
    • Compassion for animals
  • Resources
    • Virtual speaker series
    • Speakers program
    • Pamphlets
    • Newsletters
  • Blog
  • About Us
    • Who we are
    • Contact us
  • How to Help
    • Join us
    • Donate
  • Subscribe to Newsletter

We’ve outgrown omnivorism

We’ve outgrown omnivorism

We’ve outgrown omnivorism

May 10, 2016 Posted by David Steele

By David Steele and Denise Swanson

Many question whether humans are ‘naturally’ herbivores or omnivores. The omnivore camp argues that our species evolved to eat both plantsand animals. Many others agree with Mahatma Gandhi that no, humansare natural herbivores.

This time, Gandhi was wrong.

Humans evolved eating a mix of plant and animal materials. The structure of our guts and the transporters therein and the arrangementand shapes of our teeth – not to mention the wealth of fossil evidence(arrowheads, butchered animal bones, etc.) going back literally millionsof years – all point to an omnivorous past.

Natural selection favored meat eating because it allowed our ancestorsto survive in the absence of reliable supplies of edible plants. Ourhunter-gatherer forebears could flourish on fruits and berries whenthose were plentiful and switch to meat when edible plants were scarce. Had early humans not led omnivorous lives, they almost certainlywould have died out.

Yet we have continued to evolve since then. Just 10,000 years ago, isolated bands of humans invented agriculture. Around the world, we began to grow crops and domesticate animals, which, for the most part, we raised to convert grasses to meat for us. Sometime later, a mutation arose in us and we could add animal milk to our adult diets as well. And for a very long time, we have flourished.

But things have changed.

In the past, humans were few and far between. The pressure we exerted on the creatures around us was slight. In contrast, with a population of about 7 billion people – headed towards 10 billion by mid-century – the pressures we exert today are enormous. Whereas meat eating allowed humanity to survive the harsh environments of the past, doing so is now well on the way to making the environment itself uninhabitable. It is no exaggeration to state that our hunger for meat is destroying the world.

In 2005, some 55 billion farm animals were killed for food. According to the UN Food and Agriculture Organization, worldwide meat consumption, ignoring fish, increased from 156 billion pounds in 1961 to 540 billion pounds in 2002. World population doubled and meat consumption increased nearly 4-fold.

The New York Times has reported on just how destructive this accelerating production of animal products can be. As China switches from a largely soy-based diet to meat, paradoxically their demand for soy is skyrocketing. In today’s factory farms, it takes 2.4 lbs of corn, soy and oats to produce a pound of chicken, 8-10 lbs of similar feed is required for every pound of beef. Chinese demand for meat has led to a doubling of Brazilian soy exports – at a cost of huge swaths of the Amazon rainforest.

Meat production pollutes enormously. The Union of Concerned Scientists has shown that animal agriculture is second only to transportation in the pollution it causes. Twenty tons of manure is produced for every household in the United States.

And meat production accelerates global warming. According to the UN Food and Agriculture Organization, animal agriculture is the number one worldwide source of global warming gases. More than transportation, more than electrical generation.

Natural selection operates on the here and now. In the past, the ability to eat meat was a boon to us. But today, the opposite is true. If we don’t dramatically curtail our consumption of animal products, our planet will become a wasteland; natural selection will soon select in the strongest way against our meat-eating habits.

We’re lucky. We evolved as omnivores. We can choose what we eat. Plants or animals. Choose plants.

The survival of not only our species but of much of the planet is at stake.


Photo by Diana Polekhina on Unsplash

Share
Avatar photo

About David Steele

David is a molecular biologist retired in 2013 from the Faculty of Medicine at the University of British Columbia. He has also held faculty positions at Cornell and Queen’s Universities. Dr. Steele is a frequent public speaker and a regular contributor to Earthsave Canada's publications. He is also an occasional contributor to various other publications.

You also might be interested in

Food waste

9 tips to decrease your diet’s environmental impact

Feb 1, 2021

Wasted food is an important issue that we can all take action on. 63% of food thrown away by Canadian households could be avoided. Small changes can help the environment and save you money!

Blood on our hands

Animal agriculture is deadlier than you think

Sep 21, 2019

It can be easy to turn away from the impact of our decisions. Our food choices matter. They really do! This is wonderful knowledge because we can each make an enormous difference.

The biggest threat to biodiversity is on our plates

The biggest threat to biodiversity is on our plates

Mar 22, 2023

This article also appeared in print in the National Post. Research shows that our impact on the planetary biosphere is enormously damaging. And it is mostly due to what we put on our plates. The good news is we have the power to change that.

Recent Posts

  • How can we continue to honour our planet after Earth Month?
  • No, Bill C-293 on pandemic prevention is not the “Vegan Act”
  • Estimating the True Costs of Our Foods
  • CBC’s coverage of plant-based issues is all too often outrageously flawed

Follow us

If you found this helpful please consider donating.

Donate

Engage with us on facebook

Earthsave Canada

Earthsave Canada

4 hours 44 minutes ago

"Scientists have discovered that many baby animals experience grief in ways remarkably similar to humans, especially when they lose a parent, sibling, or close companion.

6
View on Facebook
Share
Earthsave Canada

Earthsave Canada

7 hours 2 minutes ago

Bottom line: Meat industry 'science' amounts to mostly lies. Quoting the study, "Our findings highlight that using animal protein as a comparator in industry-funded studies,

6
View on Facebook
Share

Earthsave Canada

9 hours 47 minutes ago

"Switching to plant-based diets could help protect our environment—and ocean life—in meaningful ways. A 2023 analysis from the University of Oxford, which studied data from

New Research Shows What Our Diets Are Doing to the Oceans: “An Existential Crisis”

New research reveals how ocean warming threatens thousands of species. Here’s how our diets could help protect them.

3
View on Facebook
Share

© 2025 · Earthsave Canada.