Vegetarianism is as old as recorded ethics. In South Asia it grew from the religious principle of ahimsa—non-harm—within Hinduism, Jainism, and Buddhism; in the Mediterranean world, Greek moralists such as Pythagoras framed meatless eating as a philosophy of compassion and self-discipline. For centuries the Western term “Pythagorean diet” even meant vegetarianism. These ancient roots show two enduring motives: a spiritual refusal to kill and a belief that diet shapes character as much as body.

The modern movement took shape in the 19th century. In Britain, reformers created the Vegetarian Society in 1847; in the U.S., physicians and ministers promoted “vegetable diet” as hygienic and morally elevating, culminating in the American Vegetarian Society (1850). William A. Alcott’s Vegetable Diet (1838) and Asenath Nicholson’s 1835 cookbook gave Americans some of the first practical guides to living meat-free.

New England Transcendentalists wrapped ethical diet in utopian aspiration. Bronson Alcott’s short-lived commune, Fruitlands (1843–44), tried an austere, near-vegan regimen as part of a total life reform. His daughter Louisa May Alcott later captured the idealism—and foibles—of the experiment in “Transcendental Wild Oats.” Even if Fruitlands failed, it linked vegetarianism to an American tradition of moral self-improvement and simplicity.

On the medical side, the hygienists—a broad current of “Natural Hygiene” thinkers—argued that clean living, simple foods, and sometimes fasting restored the body’s capacity to heal. Early figures included Sylvester Graham (of “Graham bread” fame) and Russell Thacher Trall, who both connected meatless diets to temperance, sanitation, and exercise. In the 20th century, Herbert M. Shelton popularized Natural Hygiene, advocating plant foods and fasting (controversially), and became a touchstone for later raw-food and vegan currents.

Religious reform further expanded vegetarian practice through Seventh-day Adventists. At the Battle Creek Sanitarium, physician John Harvey Kellogg prescribed vegetarian menus, exercise, hydrotherapy, and whole-grain cereals—the seedbed for modern breakfast foods. Kellogg’s fusion of diet, medicine, and industry helped normalize plant-forward eating well beyond church circles.

Alongside the hygienists were influential alternative-health authors whose books remained in circulation for generations. Arnold Ehret (1866–1922) argued for fruit-heavy, “mucusless” diets and fasting, ideas that shaped later naturopathic subcultures (even as medical critics disputed his claims). In 1939, herbalist Jethro Kloss published Back to Eden, a massive handbook of herbs, natural foods, and home remedies that became a durable reference for health-food seekers.

Vegetarianism has always had literary standard-bearers. In Victorian Britain, Henry S. Salt—author of A Plea for Vegetarianism (1886) and Animals’ Rights (1892)—made the ethical case for animals and influenced writers and reformers across Europe. Howard Williams’s The Ethics of Diet collected centuries of humane voices and reached Tolstoy and, decisively, Mahatma Gandhi, who credited Salt for clarifying why it was right to be vegetarian.

American letters also intersected with diet reform. Upton Sinclair—often confused with Sinclair Lewis—championed fasting and meatless living in The Fasting Cure (1911), extending Progressive-Era scrutiny of industrial life from the slaughterhouse to the dinner table. His earlier novel The Jungle (1906), though not a vegetarian tract, shocked readers with its brutal depiction of the meatpacking industry, unsanitary conditions, and animal suffering. While its primary impact was spurring food-safety reforms, it also stirred public revulsion at industrial meat, indirectly fueling interest in alternatives. Sinclair Lewis, for his part, did not campaign for vegetarianism, but his satires of American boosterism and health fads (Main Street, Babbitt, Arrowsmith) captured the cultural crosswinds in which dietary reformers were alternately mocked and embraced.

By the late 20th century, new writers reshaped the conversation. Frances Moore Lappé’s Diet for a Small Planet (1971) reframed meatless eating as environmental citizenship and helped retire the old myth that plant-based diets cannot supply adequate protein; Lappé popularized the idea of complementary proteins and later clarified that variety over the day—not strict combining at every meal—meets amino-acid needs. The mainstream nutrition community ultimately concurred: the Academy of Nutrition and Dietetics states that well-planned vegetarian and vegan diets are healthful and appropriate across the life cycle.

In 1987, John Robbins’s Diet for a New America drew a wide audience by linking personal health to animal welfare and ecology, persuading many readers to reconsider the ethics of industrial animal agriculture. Robbins’s work helped shift vegetarianism from a niche wellness practice to a broader social movement with environmental and animal-rights wings.

Across this history, the motives for vegetarianism—and, more recently, veganism—have ranged from purely health-oriented (longevity, weight, chronic-disease prevention) to ethical (ending animal suffering), spiritual (non-violence, purity, self-discipline), and ecological (lower land, water, and greenhouse-gas footprints). Gandhi’s vows of non-harm exemplify the spiritual motive; Salt and later animal-rights advocates articulate the ethical; Lappé and Robbins crystallize the environmental case; and the hygienists and Adventist physicians emphasize health. The mix varies by era and culture, but the shared thread is a belief that food choices are moral choices.

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