Eating more plants is often associated with a longer, healthier life. But does being vegetarian—or completely vegan—actually help people live longer?

Researchers have studied this question in large groups of people over many years. Their findings offer reasons for optimism, while also showing that the answer depends on more than whether someone eats animal foods.

What researchers measure

Most studies examine all-cause mortality: the risk of dying from any cause during a particular follow-up period. This helps researchers assess the overall balance of benefits and risks.

A lower mortality rate is relevant to longevity, but it does not tell us exactly how many extra years someone will live. A finding of 12% lower mortality does not mean a 12% longer life.

It also matters how diets are defined. Vegetarians generally avoid meat and fish but may eat eggs and dairy. Vegans avoid all animal foods. Pescatarians eat fish but avoid other meat. Some studies group several of these patterns together.

The Adventist studies: encouraging findings

The Adventist Health Study-2 follows adults in the United States and Canada. It is particularly useful because it includes many people following different vegetarian patterns.

A 2013 analysis included 73,308 participants, followed for approximately six years. Compared with nonvegetarians, the vegetarian dietary groups combined had a 12% lower relative risk of death after adjustment for factors such as age, smoking and exercise.[1]

However, that combined category included vegans, vegetarians who ate eggs or dairy, fish eaters, and people who occasionally ate meat. The result should therefore not be presented as a finding about strict vegetarians alone.

Looking at the groups separately, researchers estimated:

  • Vegans: 15% lower mortality.
  • Vegetarians eating eggs or dairy: 9% lower mortality.
  • Fish eaters avoiding other meat: 19% lower mortality.

The fish-eating group showed a statistically clear reduction. The uncertainty around the vegan estimate included no difference, while the egg-and-dairy vegetarian result was borderline. These figures are estimates, rather than a reliable ranking of the best diets.[1]

A larger analysis published in 2024 included 88,400 participants, with a median follow-up of about 11 years. It found that associations varied with age and dietary pattern. For vegans, men and women combined, there was no statistically clear reduction in overall mortality.[2]

This later report comes from the same ongoing study, so it is an update rather than an entirely independent confirmation.

The British studies: a different result

A British analysis published in 2016 combined data from the Oxford Vegetarian Study and EPIC-Oxford, covering 60,310 people.[3]

Researchers found no statistically significant difference in overall mortality between regular meat eaters, less frequent meat eaters, fish eaters, and vegetarians including vegans.

These participants were relatively health-conscious. Comparing vegetarian diets with the habits of health-conscious meat eaters may produce different results from comparing them with a less healthy population.

The British findings do not prove that diet makes no difference. They show that avoiding meat did not produce a clear overall survival advantage in that particular comparison.

The quality of the diet matters

“Vegan” and “vegetarian” describe which foods someone avoids. They do not fully describe what that person eats.

A diet built around beans, vegetables, whole grains, fruit and nuts differs considerably from one dominated by sweets, refined snacks and highly processed convenience foods—even when both are vegan.

Another Adventist analysis found that greater consumption of ultra-processed foods was associated with higher overall mortality.[4] This supports paying attention to the foods replacing meat, rather than relying on the vegetarian label alone.

What can we reasonably conclude?

Some large studies associate vegetarian dietary patterns with lower mortality. Others find similar survival among vegetarians and comparable meat eaters. Evidence that strict veganism itself extends lifespan remains less certain.

These are observational studies. Researchers account for many lifestyle differences, but cannot completely separate diet from exercise, smoking, income, healthcare and other influences.

For people choosing a plant-based diet, the research offers encouragement without a promise of extra years. A thoughtful interpretation is that food quality and the wider pattern of daily life deserve at least as much attention as the name of the diet.

Health information: This article is for general information. Consult your health practitioner before making major dietary changes, particularly if you have a medical condition or take medication.

Sources

1. Orlich MJ et al. (2013). Vegetarian Dietary Patterns and Mortality in Adventist Health Study 2. JAMA Internal Medicine. https://pmc.ncbi.nlm.nih.gov/articles/PMC4191896/ 2. Abris GP et al. (2024). Cause-specific and all-cause mortalities in vegetarian compared with those in nonvegetarian participants from the Adventist Health Study-2 cohort. American Journal of Clinical Nutrition. https://pubmed.ncbi.nlm.nih.gov/39098708/ 3. Appleby PN et al. (2016). Mortality in vegetarians and comparable nonvegetarians in the United Kingdom. American Journal of Clinical Nutrition. https://pmc.ncbi.nlm.nih.gov/articles/PMC4691673/ 4. Orlich MJ et al. (2022). Ultra-processed food intake and animal-based food intake and mortality in the Adventist Health Study-2. American Journal of Clinical Nutrition. https://www.sciencedirect.com/science/article/pii/S0002916522002842