Study analysis · JAMA internal medicine · 2013
Vegetarians live longer—but only if they eat fish?
People who eat no meat or just fish were up to 19% less likely to die during the study than meat-eaters.
Overview
What the study found
The study in plain English — the bottom line, every takeaway we extracted, and what to do with them.
In simple terms
This study watched a big group of people who ate different kinds of plant-based diets and saw who passed away over time. It found that people who didn't eat much meat tended to live longer, but it didn't prove that skipping meat made them live longer — maybe they also exercised more or didn't smoke.
What’s the bottom line?
Scientists tracked what people ate and who died over several years to see if eating less meat helps people live longer.
How strong is this study?
This study did a pretty good job because it followed so many people for years and asked them detailed questions about what they ate. But it's not perfect — everyone in the study was part of the same church group, so they might have had other healthy habits that made the difference, not just their food.
40 / 100
- COI disclosure+40/40
- Data availabilitydata not shared
- Code availabilitycode not shared
56 / 100
- Randomizationnot randomized
- Blindingblinding unclear
- Control group+15/15
- Sample size (n=73308)+20/20
- Follow-up+10/10
100 / 100
77 / 100
- P-values+15/15
- Effect size+20/20
- Confidence intervals+15/15
- Pre-registrationnot pre-registered
Each component is scored out of 100 and then capped by the study design — a case series cannot reach the ceiling a randomised trial can, however well it is reported.
Where it sits
RCT reviewsReviews of RCTs (Meta-analyses)
Max 100Randomized TrialsRandomized Trials
Max 90Reviews of Cohort StudiesReviews of Cohort Studies
Max 85Cohort StudiesCohort Studies
Max 72Reviews of Case-Control StudiesReviews of Case-Control Studies
Max 63Case-Control StudiesCase-Control Studies
Max 58Cross-Sectional & Case SeriesCross-Sectional & Case Series
Max 50Expert OpinionExpert Opinion
Max 567 / 100
Probability of being correct
Groups of people are followed over time to see who develops an outcome. Strong for identifying risk factors and associations, but cannot prove causation as firmly as RCTs.
This design cannot establish causation — the findings describe an association, not a cause. This is an observational cohort study with no randomization; while it adjusts for many confounders, unmeasured factors (e.g., genetic differences, unreported lifestyle habits, or motivation for choosing vegetarian diets) could still explain the observed associations.
Key takeaways
- 01
People who ate no meat (vegans) or only fish (pesco-vegetarians) were 15-19% less likely to die during the study than those who ate meat regularly.
- 02
This means for every 100 people who ate meat, about 6 died during the study; for vegetarians, it was about 5 or fewer — a small but meaningful difference.
Surprising findings
- Vegans didn’t have the strongest mortality benefit—pesco-vegetarians did.Most public health messaging promotes veganism as the gold standard, but this large study found fish-eaters had the lowest risk—contradicting the assumption that eliminating all animal products is optimal.
- No significant reduction in cancer mortality despite plant-rich diets.People assume plant-based diets prevent cancer, but this study found no statistically significant link—challenging a widely held belief.
Practical takeaways
Swap red meat for fish 2–3 times a week to potentially lower your risk of early death by nearly 20%.
This study only tracked one dietary snapshot—people’s diets may have changed over time, and results may not apply to non-Adventist populations.
medium confidenceIf you’re male and want to reduce diabetes or kidney disease risk, reducing meat intake—even without going fully vegan—could help.
The benefit was strongest in men; women saw little to no reduction in mortality risk from vegetarian diets in this study.
medium confidenceWhy this study matters
Pesco-vegetarians win the longevity prize
Pesco-vegetarians—those who eat fish but no other meat—had the lowest risk of death (HR 0.81), meaning they were 19% less likely to die than nonvegetarians. This beat vegans (HR 0.85) and lacto-ovo vegetarians (HR 0.91).
Most people assume vegans are the healthiest, but this study shows adding fish might be the secret sauce for longer life—challenging the idea that all plant-based diets are equal.
Men benefit way more than women
The mortality benefit was nearly twice as strong in men (HR 0.82) than in women (HR 0.93). For men, vegetarian diets cut cardiovascular death risk by 29%—a statistically significant drop.
This flips the script on nutrition advice—most health campaigns target women, but here, men get the biggest life-extending payoff from plant-based eating.
Renal and diabetes deaths dropped by half
Vegetarians had a 52% lower risk of dying from renal failure (HR 0.48) and a 39% lower risk from endocrine diseases like diabetes (HR 0.61). For men, diabetes death risk dropped by 73%.
This isn’t just about heart health—it’s about preventing silent killers like kidney failure and diabetes, which affect millions but rarely get diet-focused attention.
Want the whole report?
Detailed mode opens the full scientific breakdown — every score component, the methodology, conflicts of interest, the evidence analysis behind each claim, and the raw study data.
Overview
What the study found
The study in plain English — the bottom line, every takeaway we extracted, and what to do with them.
Not medical advice. For informational purposes only. Always consult a healthcare professional. Terms
Scientists tracked what people ate and who died over several years to see if eating less meat helps people live longer.
Research results
People who ate no meat (vegans) or only fish (pesco-vegetarians) were 15-19% less likely to die during the study than those who ate meat regularly.
What this means - more context
This means for every 100 people who ate meat, about 6 died during the study; for vegetarians, it was about 5 or fewer — a small but meaningful difference.
To evaluate whether vegetarian dietary patterns are associated with lower all-cause and cause-specific mortality in a large North American cohort.
Vegetarian diets, especially pesco-vegetarian and vegan patterns, were associated with modestly lower all-cause mortality (HR 0.88) compared to nonvegetarian diets, with stronger effects in men and significant reductions in cardiovascular, renal, and endocrine mortality.
Methods Used
Prospective cohort study of 73,308 Seventh-day Adventists followed for 5.79 years; diet assessed via food frequency questionnaire and categorized into five patterns; mortality analyzed using Cox proportional hazards regression adjusted for age, sex, race, BMI, smoking, alcohol, exercise, and other confounders.
Main Finding
All vegetarians combined had 12% lower all-cause mortality (HR 0.88, 95% CI 0.80–0.97); pesco-vegetarians had the strongest association (HR 0.81, 95% CI 0.69–0.94); effects were larger and more significant in men than women.
Confidence Level
Moderate; strong adjustment for confounders and large sample size, but limited by single baseline diet measurement, relatively short follow-up, and potential residual confounding from lifestyle factors.
Study Flags
Red Flags
- •Single baseline dietary assessment, no follow-up dietary data
- •Relatively short follow-up (5.8 years) for mortality outcomes
- •Cohort is religiously homogenous (Seventh-day Adventists), limiting generalizability
No biological mechanisms were identified in this study. This may be an epidemiological, observational, or survey-based study that reports associations rather than proposing causal biological pathways.
Surprising Findings
Vegans didn’t have the strongest mortality benefit—pesco-vegetarians did.
Most public health messaging promotes veganism as the gold standard, but this large study found fish-eaters had the lowest risk—contradicting the assumption that eliminating all animal products is optimal.
Practical Takeaways
Swap red meat for fish 2–3 times a week to potentially lower your risk of early death by nearly 20%.
RCT reviewsReviews of RCTs (Meta-analyses)
Max 100Randomized TrialsRandomized Trials
Max 90Reviews of Cohort StudiesReviews of Cohort Studies
Max 85Cohort StudiesCohort Studies
Max 72Reviews of Case-Control StudiesReviews of Case-Control Studies
Max 63Case-Control StudiesCase-Control Studies
Max 58Cross-Sectional & Case SeriesCross-Sectional & Case Series
Max 50Expert OpinionExpert Opinion
Max 567 / 100
Probability of being correct
Groups of people are followed over time to see who develops an outcome. Strong for identifying risk factors and associations, but cannot prove causation as firmly as RCTs.
Human Cohort Study
Subject
Moderate probability
on the GRADE evidence scale
This study watched a big group of people who ate different kinds of plant-based diets and saw who passed away over time. It found that people who didn't eat much meat tended to live longer, but it didn't prove that skipping meat made them live longer — maybe they also exercised more or didn't smoke.
Strengths
- Large sample size (73,308 participants)
- Long prospective follow-up (mean 5.79 years)
- Detailed dietary assessment using validated food frequency questionnaire
Weaknesses
- No randomization — cannot rule out confounding
- Diet measured only at baseline — dietary changes over time not captured
- Self-reported dietary data — potential for recall or reporting bias
Methodology
Evidence Keywords
Statistical Reporting
Not medical advice. For informational purposes only. Always consult a healthcare professional. Terms
Scientists tracked what people ate and who died over several years to see if eating less meat helps people live longer.
Research results
People who ate no meat (vegans) or only fish (pesco-vegetarians) were 15-19% less likely to die during the study than those who ate meat regularly.
What this means - more context
This means for every 100 people who ate meat, about 6 died during the study; for vegetarians, it was about 5 or fewer — a small but meaningful difference.
To evaluate whether vegetarian dietary patterns are associated with lower all-cause and cause-specific mortality in a large North American cohort.
Vegetarian diets, especially pesco-vegetarian and vegan patterns, were associated with modestly lower all-cause mortality (HR 0.88) compared to nonvegetarian diets, with stronger effects in men and significant reductions in cardiovascular, renal, and endocrine mortality.
Methods Used
Prospective cohort study of 73,308 Seventh-day Adventists followed for 5.79 years; diet assessed via food frequency questionnaire and categorized into five patterns; mortality analyzed using Cox proportional hazards regression adjusted for age, sex, race, BMI, smoking, alcohol, exercise, and other confounders.
Main Finding
All vegetarians combined had 12% lower all-cause mortality (HR 0.88, 95% CI 0.80–0.97); pesco-vegetarians had the strongest association (HR 0.81, 95% CI 0.69–0.94); effects were larger and more significant in men than women.
Confidence Level
Moderate; strong adjustment for confounders and large sample size, but limited by single baseline diet measurement, relatively short follow-up, and potential residual confounding from lifestyle factors.
Study Flags
Red Flags
- •Single baseline dietary assessment, no follow-up dietary data
- •Relatively short follow-up (5.8 years) for mortality outcomes
- •Cohort is religiously homogenous (Seventh-day Adventists), limiting generalizability
No biological mechanisms were identified in this study. This may be an epidemiological, observational, or survey-based study that reports associations rather than proposing causal biological pathways.
Surprising Findings
Vegans didn’t have the strongest mortality benefit—pesco-vegetarians did.
Most public health messaging promotes veganism as the gold standard, but this large study found fish-eaters had the lowest risk—contradicting the assumption that eliminating all animal products is optimal.
Practical Takeaways
Swap red meat for fish 2–3 times a week to potentially lower your risk of early death by nearly 20%.
RCT reviewsReviews of RCTs (Meta-analyses)
Max 100Randomized TrialsRandomized Trials
Max 90Reviews of Cohort StudiesReviews of Cohort Studies
Max 85Cohort StudiesCohort Studies
Max 72Reviews of Case-Control StudiesReviews of Case-Control Studies
Max 63Case-Control StudiesCase-Control Studies
Max 58Cross-Sectional & Case SeriesCross-Sectional & Case Series
Max 50Expert OpinionExpert Opinion
Max 567 / 100
Probability of being correct
Groups of people are followed over time to see who develops an outcome. Strong for identifying risk factors and associations, but cannot prove causation as firmly as RCTs.
Human Cohort Study
Subject
Moderate probability
on the GRADE evidence scale
This study watched a big group of people who ate different kinds of plant-based diets and saw who passed away over time. It found that people who didn't eat much meat tended to live longer, but it didn't prove that skipping meat made them live longer — maybe they also exercised more or didn't smoke.
Strengths
- Large sample size (73,308 participants)
- Long prospective follow-up (mean 5.79 years)
- Detailed dietary assessment using validated food frequency questionnaire
Weaknesses
- No randomization — cannot rule out confounding
- Diet measured only at baseline — dietary changes over time not captured
- Self-reported dietary data — potential for recall or reporting bias
Methodology
Evidence Keywords
Statistical Reporting
Scoring
How strong is this study?
This study did a pretty good job because it followed so many people for years and asked them detailed questions about what they ate. But it's not perfect — everyone in the study was part of the same church group, so they might have had other healthy habits that made the difference, not just their food.
40 / 100
- COI disclosure+40/40
- Data availabilitydata not shared
- Code availabilitycode not shared
56 / 100
- Randomizationnot randomized
- Blindingblinding unclear
- Control group+15/15
- Sample size (n=73308)+20/20
- Follow-up+10/10
100 / 100
77 / 100
- P-values+15/15
- Effect size+20/20
- Confidence intervals+15/15
- Pre-registrationnot pre-registered
Each component is scored out of 100 and then capped by the study design — a case series cannot reach the ceiling a randomised trial can, however well it is reported.
Where it sits
RCT reviewsReviews of RCTs (Meta-analyses)
Max 100Randomized TrialsRandomized Trials
Max 90Reviews of Cohort StudiesReviews of Cohort Studies
Max 85Cohort StudiesCohort Studies
Max 72Reviews of Case-Control StudiesReviews of Case-Control Studies
Max 63Case-Control StudiesCase-Control Studies
Max 58Cross-Sectional & Case SeriesCross-Sectional & Case Series
Max 50Expert OpinionExpert Opinion
Max 567 / 100
Probability of being correct
Groups of people are followed over time to see who develops an outcome. Strong for identifying risk factors and associations, but cannot prove causation as firmly as RCTs.
This design cannot establish causation — the findings describe an association, not a cause. This is an observational cohort study with no randomization; while it adjusts for many confounders, unmeasured factors (e.g., genetic differences, unreported lifestyle habits, or motivation for choosing vegetarian diets) could still explain the observed associations.
Standing
Who’s using this study?
The videos and claims on this site that lean on this study, and the researchers who wrote it.
1 video from Nutrition Made Simple! cite this study, drawing 1 claim from it.
- Very strong evidence
Randomized or controlled trials support this claim, alongside consistent supporting evidence.
Evidence