People go vegetarian for a mix of reasons, but most fall into a few major categories: ethics, health, religion, environmental concerns, and cost. In surveys, a majority of vegetarians say their primary motivation is ethical, whether that means concern for animals, the planet, or both. Others start for health reasons and stay for the broader benefits. About 5% of Americans identify as vegetarian, with the highest rates (8%) among young adults ages 18 to 34.
Animal Welfare and Ethics
For many vegetarians, the decision comes down to a simple question: is the way we treat animals for food acceptable? The answer, for them, is no. In the broader research on vegetarian motivations, a majority cite ethical concerns as their primary reason, including objections to how the meat industry operates and what it requires of animals.
The scale of modern animal agriculture makes these concerns feel urgent. Most egg-laying hens spend their lives in spaces roughly the size of a sheet of typing paper. The United Nations Food and Agriculture Organization projects that less industrialized countries will increase animal product production by 2.5% to 3% annually, meaning global demand is growing, not shrinking. For people motivated by animal welfare, choosing not to eat meat is the most direct action they can take.
Health Benefits
Vegetarian diets are linked to lower risks of several major diseases. A large longitudinal study from Loma Linda University found that vegetarian diets were associated with a 12% overall reduced risk of all cancers. The reductions were even sharper for specific types: stomach cancer risk dropped by as much as 45%, lymphoma risk by 25%, and colorectal cancer risk by about 20%. Vegans in the same study population had roughly 25% lower risks of breast and prostate cancers.
Beyond cancer, plant-heavy diets tend to be lower in saturated fat and higher in fiber, which benefits cardiovascular health and blood sugar regulation. Some people switch to a vegetarian diet after a health scare or a diagnosis of high cholesterol or prediabetes. Others are drawn by the long-term data showing that populations eating less meat consistently live longer and develop fewer chronic diseases.
The World Health Organization’s cancer research arm classifies processed meat (bacon, sausages, deli meats) as a Group 1 carcinogen, meaning there is sufficient evidence that it causes cancer in humans. Red meat is classified as Group 2A, probably carcinogenic. These classifications don’t mean eating a hot dog is as dangerous as smoking, but they do confirm a real, measurable risk that motivates some people to cut meat out entirely.
Religious and Cultural Traditions
Vegetarianism is deeply embedded in several world religions, each with its own reasoning.
In Hinduism, the practice is closely tied to ahimsa, the principle of nonviolence toward living beings. Because Hindu theology holds that souls pass through different bodies across lifetimes, harming any creature carries consequences for karma. The Krishna tradition, in particular, gave rise to the reverence for cows that many associate with Hindu culture today. Hundreds of millions of people in India follow some form of vegetarian diet rooted in these beliefs.
Jainism takes ahimsa further than perhaps any other tradition. Jains view the entire universe as alive and believe that purifying the soul requires minimizing violence toward all creatures. Their vegetarianism is part of a broader ascetic practice aimed at freeing the soul from its entanglement with the material world. Many Jains avoid not just meat but also root vegetables, since harvesting them kills the whole plant.
Buddhism encourages compassion for all sentient life. The Buddha instructed monks to abstain from killing animals, and both major branches of Buddhism developed strong arguments for meatless diets. The reasoning centers on the idea that craving flesh and participating in slaughter keep people trapped in cycles of suffering and desire.
Seventh-day Adventism, a Christian denomination, promotes vegetarianism as a return to what they see as God’s original design for human eating. Adventist teachings hold that eating meat dulls both physical health and moral sensitivity. The Adventist population has been the subject of some of the most rigorous nutrition research in the world, and their health outcomes consistently outperform national averages.
Environmental Impact
Raising animals for food uses far more land, water, and energy than growing plants directly for human consumption. Livestock farming is a major source of greenhouse gas emissions, deforestation, and water pollution. For environmentally motivated vegetarians, skipping meat is one of the most impactful individual choices they can make to reduce their carbon footprint.
This motivation often overlaps with ethical concerns. Someone might start by caring about animals and then learn about the environmental toll, or vice versa. Among younger adults, environmental reasons are an increasingly common entry point into vegetarianism.
Cost of a Vegetarian Diet
A vegetarian diet can be cheaper than an omnivorous one, though the savings depend on what you buy. A study comparing food costs among children and adolescents found that vegetarians spent the least per calorie: about 2.52 euros per 1,000 calories, compared to 2.83 for omnivores and 2.98 for vegans. In daily totals, vegetarians spent roughly 4.37 euros per day on food versus 4.75 for omnivores.
The savings come from replacing expensive items like meat and fish with cheaper staples: beans, lentils, rice, pasta, and seasonal vegetables. Specialty meat substitutes and organic produce can push costs up, but a straightforward whole-foods vegetarian diet is consistently one of the most affordable ways to eat well.
Nutritional Considerations
Vegetarian diets can meet all nutritional needs, but vitamin B12 deserves real attention. B12 is found naturally almost exclusively in animal products. Among vegetarians who don’t supplement, deficiency rates are strikingly high: studies have found rates of 25% to 85% in vegetarian children and 21% to 41% in vegetarian adolescents, depending on the population. B12 deficiency can cause fatigue, nerve damage, and cognitive problems, so supplementation or fortified foods (like certain cereals and plant milks) are essential for anyone avoiding meat long-term.
Iron and zinc are sometimes flagged as concerns, but the evidence is more reassuring. Reported iron deficiency anemia from vegetarian diets alone is rare. Zinc intake in vegetarian children tends to be similar to that of meat-eating children in most studies, with comparable blood levels. Eating a variety of whole grains, legumes, nuts, and seeds generally covers these minerals without much extra effort.
Other Personal Reasons
Not every vegetarian has a grand philosophical motivation. Some people simply don’t like the taste or texture of meat. Researchers categorize this as a hedonic preference or disgust response, and it’s more common than you might expect. Others adopt a vegetarian diet primarily for weight control. College-age adults, in particular, sometimes combine health and weight motivations when making the switch, though this overlap can occasionally signal disordered eating patterns rather than a purely nutritional choice.
For many long-term vegetarians, the motivation evolves over time. Someone who started for health reasons may develop stronger ethical convictions. Someone raised vegetarian for religious reasons may find the environmental argument equally compelling as an adult. The reasons stack, and that layering often makes the diet feel less like a restriction and more like a natural fit.