Vegetarian
A vegetarian excluded any meat-based foods from their diets, either as a personal choice or as part of their culture. They were not to be confused with herbivores, whose natural diet consisted solely of plant-based foods.

It was once noted by Spock that, as plants were living organisms, vegetarians and meat-eaters alike feed on death. ()

On early 21st century Earth, the term "Veggie" might be used for such a person. ()

Vulcans
Most Vulcans, including T'Pol and Spock, were vegetarians. (; ) The v'tosh ka'tur were a major exception, however. ()

Humans
By 2364, Humans in the United Federation of Planets no longer enslaved animals for food purposes, although "meat" remained available, and continued to be eaten, in the form of the inorganically materialized output of replicators. An Antican ambassador, who insisted on slaughtering live animals for food, considered this practice to to be "sickening" and "barbaric." ()

The inhabitants of Omicron Ceti III were forced to be vegetarians, after all the animals there died. ()

Commander Tucker once inquired if Colonel Grat was a vegetarian, during a dinner invite in 2152. ()

Some Humans, like Chakotay, also chose the life of a vegetarian as an expression of their spiritual beliefs (.)

Other species
The Trill Tobin Dax was also a vegetarian ().

Deanna Troi became concerned that the Evora may be vegetarians after they began eating the floral arrangements at their reception in 2375. ()

See also 
Herbivore

External link
 

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Victual culture