Somewhere between 5-6% of Americans are vegetarians (according to a 2012 Gallup pole) and 8-10% of Germans identify themselves as vegetarians. I see videos on my Facebook newsfeed, on a daily basis, aimed at convincing me that eating meat is unethical and that we need to stop supporting the meat industries immediately. Although their goal is something I can connect with, their arguments are far weaker than they could be.

I am being pretty constantly berated with emotional arguments to become a vegetarian: as if the suffering of animals would be sufficient to change cultural and social norms regarding food habits. If the suffering of humans who are mining rare earth minerals in the Congo, or the slave labor of Chinese workers, is insufficient to stop people from buying smartphones: why would the non-human suffering of beings most of us are prepared to eat be enough to change the minds of more than a few percent?

I can understand that these emotional arguments work with some people, but why are these moral crusaders often unaware of, in my opinion, the much stronger rational arguments? The absolutely most shocking and most important reason to avoid meat and factory farms lays somehow well hidden in the world of ecology: trophic efficiency.


A great diagram from Pearson Biology, illustrating the loss of energy as it moves up the trophic ladder

Trophic efficiency is the little known phenomenon that makes you being able to buy a burger for $1 (while a tomato-avacado sandwhich costs $2.50) seem like the most insane and backwards thing around. Trophic efficiency can be thought of as the reason that the “food web” can often be displayed as a pyramid: each level of consumption loses energy as it moves to a higher level.

When you eat that burger, you are functioning as a secondary consumer. From the original 1,000,000 J of sunlight that the plant absorbed, it stored 10,000 J as biomass. The primary consumer, in this case a cow, eats these plants and stores approximately 1,000 J of that energy as biomass, the rest is lost as heat, regulatory processes, and waste. You then come and eat that cow, taking in that 1,000 J of biomass and saving approximately 100 J as your own biomass (you, much like the cow below you, lose approximately 90% of the energy as heat and waste).

That tomato-avacado sandwich actually contains about 10x more calories, for the same investment of sunlight and less water, than the cow. The ecological cost of eating meat, compared to simply eating the plants these animals are fed, is approximately 10 times higher. That means that your one burger, had those plants not been fed to that cow, could have instead been enough energy to feed you in addition to 9 other people.

When people talk about food scarcity, primarily we are talking about an inability of people to buy the food. Many nations experiencing hunger and starvation are simultaneously exporting food and cash crops to markets that are willing to pay more. Within the United States, we are using huge swaths of farmland simply to produce animal feed and ethanol.


As you can see from this diagram (borrowed from Joe Satran of the Huffington Post), the vast majority of agricultural land in the United States is used for meat production (another relatively big slice is used for ethanol, which is a stupid idea, but an idea I will not cover in this text). When we take our newfound understanding of trophic efficiency and apply it to this map, we inevitably start to wonder how many people we could actually feed.

To me, the most convincing argument for vegetarianism is not the suffering of animals, but the unbelievable waste of resources and the fact that the financial costs of our food in no way reflect their ecological costs. So instead of asking if my burger tastes like murder and suffering, why not ask whether I would have rather fed an additional 9 people?