Research has indicated that vegetarians live on average 9.5 years longer than meateaters (if male) and 6.1 years longer (if female), giving an overall average of about 8 years longer. That is similar to the gap between non-smokers and smokers.

Clearly other factors apart from diet are also involved. For example, the referenced research found that vegetarians are on average 14kg (30lb, or 2 stones and 2 pounds) lighter than meateaters. And diets vary among vegetarians, as they also vary among meateaters. Nonetheless, that is still very interesting research.

My question is this:

has there been any similar research on veganism?

For example, has there been a study comparing vegans with non-vegan vegetarians for life expectancy, or for that matter vegans with meateaters?

  • Peripheral to your question really but I want to mention that the context of the study you mentioned is important - all of its subjects are Californians. In other areas, vegetarians may not have better life expectancy than non-vegetarians
    – Zanna
    Sep 6, 2022 at 17:03
  • There are many factors that influence life expectancy and the issue is very complex. I don't think there's any comprehensive study out there comparing vegans and vegetarians when it comes to life expectancy. Perhaps there are only individual studies on various factors/causes of illnesses/pre-mature deaths among people. Sep 6, 2022 at 21:23
  • There are studies such as this.
    – user5710
    Sep 7, 2022 at 0:46

1 Answer 1


There is some data available from a study on Seventh Day Adventists by Orlich et al. The sample size was 73,308.

The rates for all-cause mortality were as follows (lower is better, where 1 is a standard omnivorous diet):

  • All vegetarians 0.88
  • Vegans 0.85
  • Lacto-ovo vegetarians 0.91
  • Pescatarians 0.81
  • Semi-vegetarians 0.92

It should be noted there there are other studies such as this and this which, whilst they don't look specifically at vegans, give slightly less flattering results for vegetarians when it comes to all-cause mortality - although the risk for specific diseases was lower.

  • Many thanks for this. Those are hazard ratios. I wonder whether there is a way to pull out a Q&D estimate of a life expectancy differential using those figures and some reasonable assumptions. If we were utterly Q&D we could go from 0.88 -> (9.5y,6.1y;7.8y) to 0.85 -> (0.15/0.12)*(9.5y,6.1y;7.8y) =(11.9y,7.6y;9.8y).
    – user5710
    Sep 10, 2022 at 12:26

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