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What are the pros and cons of vegetarianism?
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Humans aren't meant to eat meat

Humans aren't evolutionarily adapted to eat meat, which has never been our natural diet.

The Argument

Human teeth didn't evolve to eat meat. Carnivores such as dogs, tigers, and lions all have carnassial teeth, which are perfect for tearing and slicing meat. Humans do not have carnassial teeth. Although humans have canine teeth, they're not meant for processing meat. In fact, animals such as gorillas and deer have even larger and sharper canines, but they're vegetarian.[1] Further, our digestive systems are much more comparable to herbivores. In humans and other herbivores, salivary glands produce the enzyme amylase, which help break down complex carbohydrates. However, there are no carbohydrates in meat, so carnivores do not produce this enzyme at all. The human intestine is also long and coiled in order to slow down digestion and absorb as many nutrients as possible from plant-based foods. In contrast, carnivores have short and straight intestines. Carnivores also have the unlimited capacity to process and excrete cholesterol. Humans do not have this capability because we're not meant to eat meat, and plants do not have cholesterol.[2]

Counter arguments

Without meat, we wouldn't have evolved to be the humans we are today. Humans probably were herbivorous at some point in the past, but a diet composed solely of vegetables and fruits isn't calorie-dense. The predecessor to Homo sapiens, Homo erectus, had "smaller teeth, reduced chewing muscles, weaker maximum bite force capabilities, and a relatively smaller gut" than earlier hominids.[3] This can be explained by the increase of meat in their diet, which requires less force and time to chew than root vegetables. We don't need large carnassial teeth like other carnivores because we learned to process the meat instead of tearing muscle straight from an animal carcass.[4] Our ability to process the meat probably led to structural changes in the skull and neck, including a larger, more developed brain. Moreover, cooking didn't exist until 500,000 years ago while Homo erectus have been around since two million years ago, meaning that we are capable of eating meat even without cooking it, which makes the meat even softer and easier to chew. Hence, humans are meant to eat meat and wouldn't have evolved to have the head and neck structure we have today without it.



[P1] Humans don't have the evolutionary adaptations for eating meat.

Rejecting the premises

[Rejecting P1] Without eating meat, we wouldn't have evolved to be the humans we are today.


This page was last edited on Tuesday, 19 May 2020 at 04:27 UTC

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