Vegetarianism explained in 60 seconds: ideas that changed the world

How meat-free diets went from religious abstention to global sustainability trend

Illustration of vegetarian diet, Pythagoras and animal rights protests
(Image credit: Illustrated / Getty Images)

In this series, The Week looks at the ideas and innovations that permanently changed the way we see the world.

Vegetarianism in 60 seconds

Vegetarianism is the practice of abstaining from eating all forms of animal flesh such as meat, fish, seafood and any fowl. Vegetarians also avoid food containing products that derive from animals, such as gelatine (obtained from animal tissue, and often found in sweets) and rennet (an enzyme from the stomach lining of calves, used in some cheeses).

In the West, vegetarianism is generally understood as ovo-lacto-vegetarianism, which allows for consumption of eggs, milk and dairy products. However, "most vegetarians in India exclude them", explains Encyclopaedia Britannica, following lacto-vegetarianism – "as did those in the Mediterranean lands in Classical times". Ovo-vegetarians avoid dairy products but consume eggs – usually due to concerns about the milk production industry.

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According to the Vegetarian Society, in 2019 about 4.5% of the UK population followed a vegetarian or vegan diet but ate 17% less meat in 2019 than in 2008. A separate Gallup poll put the US vegetarian or vegan population at 5%.

A 2010 report by The Economic and Social Research Institute suggested that more than 1.5 Billion people worldwide ate no meat. However, only 75 million were vegetarians by choice – more the other 1,450 were "vegetarians out of necessity", and would start to eat meat "as soon as" they could afford it.

How did it develop?

Vegetarianism has a long, rich history on the Indian subcontinent, where the first written references to the practice date back to 700BC. Hindu texts "often praise vegetarianism", and many Hindus avoid eating beef "because cows are traditionally viewed as sacred", said the Pew Research Center. In Islam, pork is prohibited. In 2021, the "vast majority" of Indian adults (81%) followed some restrictions on meat in their diet, such as refraining from meat on certain days – but only 39% of Indian adults described themselves as "vegetarian". 

In the West, religious restrictions on meat consumption were once common – Christians traditionally abstained from animal flesh on Fridays, choosing fish instead – but elective vegetarianism as a lifestyle had historically been a niche practice. However, there are recorded accounts of vegetarians in Ancient Greece, including the mathematician Pythagoras. Until the word vegetarian was coined in the 19th century, "it was Pythagoras's name that was used to describe a diet that excluded animal flesh", said Business Insider: a "Pythagorean" diet.

In the first half of the 19th century, “the backdrop of health reform, the temperance movement, and the rise of philanthropy set the scene for the convergence of groups that eventually formed the vegetarian movement”, says the Vegetarian Society.

Most early advocates of vegetarianism were motivated by religious considerations. Wary of the “brutalising” effect of eating meat, they believed that a vegetarian diet would create a more temperate, civilised and Christian society. From the late 1800s, secular converts began joining the cause, driven by the perceived health benefits of a meat-free diet, a moral objection to the suffering of animals and by the growing popularity of simple living. 

But even by the latter half of the 20th century, vegetarianism was "a strange if not heretical way of nourishing oneself", said The New York Times – until Frances Moore Lappé's "hugely influential" book about food and sustainability, "Diet for a Small Planet", was published in 1971. Lappé argued that both body and planet would benefit from a plant-focussed diet. The "unlikely bestseller" is often credited with bringing vegetarianism into the mainstream, and by 2021 had sold more than 3 million copies. Lappé "was 'plant-based' long before the term existed", said the paper. 

Recent years have also seen the growth in popularity, both for health and environmental reasons, of "flexitarianism": followers eat a mostly vegetarian, or low-meat diet, but do not forgo meat altogether.

How did it change the world?

By the early 20th century, "vegetarianism in the West was contributing substantially to the drive to vary and lighten the non-vegetarian diet", said the Encyclopedia Britannica. Aided by the discovery of the first vitamin, in 1913, vegetables became seen as a core component of a healthy diet, and as worthy of attention as meat.

Vegetarianism also has a long association with social activism. In the 19th century, the American Vegetarian Society’s journal "connected vegetarianism to a number of other reform movements, including women’s rights and the abolition of slavery", says the Smithsonian magazine. By the 20th century, it had become increasingly entwined with environmental activism, due to the destructive impact of industrial meat production. 

While vegetarianism "is generally perceived to be a new phenomenon, plant-based diets have deep historical roots, and a long-standing connection with the political left", wrote Sky Duthie, a PhD candidate in history at the University of York, for The Conversation.

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