Strict vegetarianism, no root vegetables

Jains affirm a strict vegetarianism that goes further than most, extending non-harm to the smallest forms of life. Devout Jains avoid not only meat, fish, and eggs but also root vegetables such as potatoes, onions, and garlic, because uprooting the plant kills it and because roots are held to harbour innumerable minute one-sensed beings (and, in traditional understanding, colonies of subtle organisms called nigodas). Many also filter water, avoid eating after dark to prevent harming insects, and restrict foods thought to contain or breed many lives.

The classification underlying this practice traces to Umasvati's Tattvartha Sutra, the earliest systematic exposition of Jain doctrine, accepted as authoritative by both Digambara and Svetambara Jains despite their other disagreements, probably composed sometime between the second and fifth centuries CE. It sets out the taxonomy of beings by the number of senses they possess, from one-sensed life in earth, water, fire, air, and plants up to five-sensed animals and humans, and treats even one-sensed beings as possessing life (jiva) whose harm generates karmic consequence, the philosophical basis teachers of the tradition cite when explaining why root vegetables, understood to harbor concentrated one-sensed and nigoda life, are avoided even though such caution goes well beyond what most other vegetarian traditions in India observe.

The dietary discipline is a direct application of Jain non-violence, which classifies beings by the number of senses they possess and seeks to minimise harm even to the one-sensed life in plants, water, and earth. It is affirmed by both the Digambara and Svetambara traditions, with ascetics keeping it most rigorously and laypeople following it in degrees. The practice makes Jainism's ahimsa unusually concrete and thoroughgoing, distinguishing it from the vegetarianism of neighbouring Hindu and Buddhist traditions, which do not as a rule extend the same scruple to roots and micro-organisms.

In diaspora Jain communities, where root vegetables are dietary staples and avoiding them entirely can be practically difficult, the rule has become a matter of individual and family conscience more than uniform enforcement, with observance ranging from strict lifelong avoidance among the most traditionally minded to occasional or symbolic abstention, particularly during festivals such as Paryushana, among others who keep most of Jain dietary practice but relax this specific restriction; teachers within the tradition generally treat the underlying principle of minimizing harm as binding while acknowledging that its most demanding applications have always required a degree of practical judgment about what a given household can sustain.