Elizabeth comments on Why you should eat meat—even if you hate factory farming

Elizabeth 27 Sep 2025 19:19 UTC
22 points
4
Your own screenshot shows that pescatarians do better than vegans (not statistically significant, but neither is the difference between vegans and omnivores). And if you break it down by sex (and continue to ignore statistical significance), veganism is the worst choice for women after unconstrained omnivorism
More of my opinion of this study here.
- Natália 27 Sep 2025 19:28 UTC
  14 points
  14
  Parent
  Your own screenshot shows that pescatarians do better than vegans (not statistically significant, but neither is the difference between vegans and omnivores). And if you break it down by sex (and continue to ignore statistical significance), veganism is the worst choice for women after unconstrained omnivorism
  I addressed both of those points in my comment above. From my comment:
  The pescatarian mortality rate appears slightly lower than the vegan one, but in practice the difference is too small and the confidence intervals are too wide to tease out which one is actually lower. When broken down by sex, nearly all of the effect is concentrated in men, while all diets are pretty similar to each other in women.
  To explain this more in-depth, you cannot conclude from this table that “veganism is the worst choice for women after unconstrained omnivorism.” The confidence intervals of the adjusted hazard ratios for the “vegetarian” diets for women are essentially identical. It’s not just about failing to meet an arbitrary threshold of statistical significance—the difference between those diets has a very high p-value, not a p-value that almost approaches significance but falls just short of it.
  Meanwhile, the adjusted hazard ratio of veganism is significant in men, compared to omnivorism. Quoting from my old comment:
  The 95% confidence intervals of the adjusted hazard ratios for overall mortality, for men, were [0.56, 0.92] and [0.57, 0.93] for vegan and pescatarian diets, respectively, and for women the CIs are [0.72, 1.07] and [0.78, 1.20], respectively. For women, the confidence intervals for all diets are [0.78, 1.2], [0.83, 1.07], [0.72, 1.07] and [0.7, 1.22].
  What these CIs indicate is that there was likely no difference between pescatarian and vegan diets for men, both of which are better than omnivorism, and likely no difference between any of the diets for women.
  The CIs for women specifically look so similar that you could pretend that all of those CIs came from different studies examining the exact same diet, and write a meta-analysis with them, and readers of the meta-analysis would think, “oh, cool, there’s no heterogeneity among the studies!”
  In fact, we can go ahead and run a meta-analysis of those aHRs (the ones for women), pretending they’re all for the same diet, and quantitatively check the heterogeneity we get. Doing so, with a random-effects meta-analysis, we find that the $I^{2}$ is exactly 0%, as is the $τ^{2}$ . The p-value for heterogeneity is 0.92. Whereas this study should update us a little bit on pescatarian diets being better than vegan diets for women, these differences are almost certainly due to chance. No one would suspect that these are actually different diets if you had a meta-analysis with those numbers.
  Since the total meta-analytic aHR is also very close to 1, it also looks like none of the diets are meaningfully associated with increased or decreased mortality for women, though there was a slight trend towards lower mortality compared to the nonvegetarian reference diet (p-value: 0.11).