Study design & scope: This was a meta-analysis, published online October 6, 2021, examining 20 studies (through June 2020) covering 171,802 participants—157,778 meat eaters and 13,259 meat abstainers (vegetarians/vegans)
Main findings:
Depression: Meat consumers reported significantly lower levels of depression compared to meat abstainers. The effect size (Hedges’s g) was 0.216 (95% CI: 0.14–0.30), p < .001, indicating a small but reliable advantage.
Anxiety: Similarly, meat consumption was linked to lower anxiety (g = 0.17, 95% CI: 0.03–0.31), p = .02.
Omnivores vs vegans: Comparing meat eaters to vegans specifically, omnivores had lower depression (g = 0.26, 95% CI: 0.01–0.51, p = .041), though the anxiety difference (g = 0.15) wasn’t statistically significant (p = .598).
Moderators & heterogeneity:
Gender did not significantly change these associations.
Study quality explained much of the variability—in fact, more rigorous studies showed larger and more consistent benefits of meat consumption on mental health (58% heterogeneity for depression, 76% for anxiety).
Limits:
The meta-analysis is observational—so causality or directionality can’t be determined (e.g., whether poor mental health leads to dietary change or vice versa).
There appears to be a small but statistically significant association suggesting that consuming meat correlates with lower depression and anxiety symptoms compared to abstaining from meat. The fact that this effect grows stronger in higher-quality studies strengthens confidence in the finding. However, it’s important to keep in mind:
Being a meta-analysis of observational data, it doesn’t prove meat causes better mental health.
The effect sizes are modest, indicating meat is just one of many factors affecting mental well-being.
Underlying reasons could include nutrients more abundant in meats—like vitamin B12, zinc, creatine—but this analysis didn't test mechanisms directly.
Meta-analysis of 171,800+ individuals shows meat-eaters report modestly lower depression and anxiety than vegetarians/vegans, especially in higher-quality studies—but causality remains unproven.
Source: https://www.tandfonline.com/doi/full/10.1080/10408398.2021.1974336#d1e206 X: https://x.com/NTFabiano/status/1939291854396121498
