Again? Aren't the eight thousand answers on Quora enough? I'll be quick then.
Environmental reasons
You eliminate the second cause of global pollution — since you can't do anything about the first one (energy production) as an individual. Source: any aggregated institutional emissions study. You'll always find disaggregated graphs denying this, but they're scientifically wrong because the atmosphere isn't divided into compartments: the planet is one.
You eliminate the leading cause of antibiotic-resistant bacteria that could kill you tomorrow. 80% of antibiotics are wasted in farms. Source: WHO and United Nations.
You eliminate the leading cause of fish disappearance. Fish-eaters have killed three-quarters of global fish stocks. Having no fish in the oceans is catastrophic: you destroy the ecological chains that absorb emissions and sustain life on land.
You stop the Amazon rainforest from being destroyed. 99% of cleared virgin land is used to grow feed for livestock. In Europe you can't grow GMO soy, so multinationals cut forest in South America, plant soy, ship it to Europe in containers for our farms. Do you grasp the pollution in this process?
Economic reasons
You solve the waste of agricultural resources that starves entire regions. Livestock farming consumes 80% of agricultural products. If you don't eat animals, you recover that 80% and lower average agricultural prices. You stop stealing fertile land from poor countries.
Anyone claiming livestock feed comes from land unsuitable for human agriculture is either ignorant or lying. What do you think cows eat? Aloe vera? Cacti? Farm animals compete with us for fertile land.
You spend less. Easy one.
You waste fewer taxes. The meat industry is so inefficient it needs tens of billions in public subsidies annually to survive. Imagine if that money could go to schools, healthcare, poverty.
Health reasons
We're an omnivorous species that's naturally inclined toward vegetarianism. Just like all other primates. We do better eating very few or no animal products. Our metabolism is built to perform best with whole grains, plant proteins, fiber, unsaturated fats, and vitamins.
It's no coincidence that after a heart attack or tumor diagnosis, the first advice is to switch to a vegetarian diet. Meta-reviews describe better life expectancy for non-meat-eaters. Smart people respect the precautionary principle: if all evidence points toward better health on a plant-based diet, doesn't it make sense to follow that path?
The conclusion
While it's true that many vegetarians are fools (like me), it's also true that most of history's great thinkers were vegetarian for the reasons above. It's simply a more logical choice.
I'll always defend anyone who doesn't want to be vegetarian — as long as it's legal. But I'll destroy anyone who denies the facts above to feel less guilty or spread nonsense. Freedom of choice is sacred, as is the need to choose in an informed way — not with blinders on.
