I had a heated discussion recently in the comment section under my article about the worst arguments against vegetarian nutrition (which explains why the most common arguments against vegetarianism do not make sense). The person who commented (let’s call him Mark, because his name is Mark) wrote:
and then he went on a rant about vegetarianism being “unnatural”, “illogical”, and “unscientific”, implying that vegetarians are stupid (and supporting his arguments with statements like “I am probably better educated than you” and “I am a STEM person” instead of citing sources).
What Mark wrote about anthropological evidence is correct, but his conclusions are completely wrong. Just because some human behaviour was uncommon in the past does not imply that it is necessarily inappropriate in the present. Consider using a toothpaste, for example:
In fact, using toothpaste further exacerbates problems with wisdom teeth, since we no longer lose teeth that could potentially make room for wisdom teeth. Yet, everybody would agree that having your wisdom teeth surgically removed is a better option than letting your second molars rot and fall out.
When vegetarianism is discussed, there are three main aspects to consider: nutrition, ecology, and ethics, because those are the things that influence our lives. Mark’s argument falls apart in all three areas.
The first (and for most people probably the most important) issue is nutrition. It is completely irrelevant how much meat people ate thousands of years ago (just like how much toothpaste they used). The important question is whether vegetarian nutrition is appropriate for individuals now, and that can only be tested with clinical studies.
There have been thousands of prospective and retrospective studies scrutinizing vegetarian nutrition, and the evidence is crystal clear. The Academy of Nutrition and Dietetics (formerly known as the American Dietetic Association), the largest organization of food and nutrition professionals in the United States, summarized it in the following statement:
It would be reasonable to use Mark’s argument to formulate a scientific theory that vegetarian nutrition is unhealthy for humans—that’s a meaningful and testable theory. Unfortunately for Mark, the theory must be rejected under the weight of evidence.
When it comes to ecology, I believe it is clear that Mark’s remarks are completely irrelevant. We face ecological issues and overpopulation that did not exist a hundred years ago, let alone during the evolution of modern humans.
Meat production is one of the major sources of pollution in the world. The United Nations Environment Programme issued a report reading:
Vegetarian nutrition is more ecological (that is, produces less pollution while providing the same amount of nutrients) than non-vegetarian nutrition. That’s a scientific fact, so one cannot simply dismiss vegetarian nutrition as “unscientific” or “illogical”.
Finally, there’s the question of ethics. Whether we like it or not, ethics and moral standards are subjective. There is probably nothing objectively right or wrong (and even if there is, there is no way for us to know). There are only things people consider right or wrong, and no two people share exactly the same set of moral views.
Does Mark’s argument make sense when it comes to morality? In other words, does the fact that the most successful societies in the past did not consider killing animals immoral make the moral judgement of modern vegetarians “unnatural”?
Again, there is a very simple counterexample. For most of human history, slavery was considered a natural part of human society; even the Bible approves of slavery. Virtually all successful civilizations used slaves. Nonetheless, slavery was eventually abolished and is now widely considered immoral.
This example shows that what is considered moral or immoral is not based on anthropological evidence. We could debate endlessly whether killing animals for food is morally acceptable, but Mark’s statement cannot be interpreted as an argument against vegetarianism.