Image from http://ourfoodprint.com/learn/diets-foodprint

Many a debate has come to pass over whether eating meat (or animal products more generally) can be “sustainable.” But if we dissect the meaning of the term “sustainable” and take into account a mind-numbingly simple math equation inherent in animal agriculture it becomes clear that this debate is largely about alleviating the guilt of omnivores than it is about figuring out how to stop our planet from becoming uninhabitable.

“Sustainability” is necessarily a relative term; it is impossible to live without consuming food, and food cannot grow without water and nutrients. Until such time as we invent a manner of producing calories out of thin air, we will be unable to exist without the expenditure of resources necessary to grow plants.

Therefore, the question is not between using resources or not using resources (because the latter is untenable), but a matter of degree. Sustainability, then, must be about consuming the foods that require the least amount of resources.

And plants will always be preferable to animal foods based on this principle. The animals many of us eat consume plants, of course. The animals then grow until they are slaughtered and cut into hunks of meat. The nutrients from the plants the animals eat is converted into meat for the omnivore.

It goes like this:

Plants→animals→humans

The obvious alternative is to eat the plants directly, like this:

Plants→humans

You can probably guess where I’m going from here. We’ve all seen a food chain before, and we all know (though some of us seem to forget) that there is always a loss of energy as the calories travel from one consumer to the next.

Image from http://www.tutorvista.com/content/science/science-ii/environment/food-chain.php

Producing plants for animals to consume so that humans can eat their meat necessarily results in a loss of energy along the way. Animals aren’t just chunks of meat waiting to be cooked; they have organs, skin, and bones that never make it to your plate, and which require calories to maintain. Like converting a signal from analog to digital and back to analog, the process necessarily involved in consuming animals produces waste. And lots of it.

Not only does consuming plants directly rather than filtering them through the bodies of animals produce far less greenhouse gases and save monstrous amounts of water and land, it also saves scores of the small, furry creatures as well.

Mice, rabbits, and other mammals which tend to live in fields are inevitably killed during crop harvesting, and bringing this up is a common way omnivores try to make vegans feel as if they’re not doing anyone any favors. But the reality is that far more crops are required to feed animals raised for meat than are required if we feed the plants to humans directly. Again, it’s a matter of conversion loss: each calorie eaten by an animal does not result in another calorie added to their meat upon slaughter.

That’s the equation. And if you do the math, you’ll find that arguing that meat is “sustainable” is a bit like saying that driving a semi-truck instead of your bike to the grocery store can be eco-friendly.

If you care about sustainability and climate change, there is but one conclusion when it comes to diet: eat more plants.