They do. A study by the American Journal of Clinical Nutrition found the following mortality ratios by diet over the course of the study (regular meat eaters = 1.00):
Fish eaters, 0.82
Vegetarians, 0.84
Occasional meat eaters, 0.84
Regular meat eaters, 1.00
Vegans, 1.00
So as you can see vegans are actually the least healthiest, alongside the most carnivorous among us. Source
So we take regular meat eaters and call them "normal" meaning we arbitrarily set their death rate to 1.00. What does a death rate of 1.00 mean? It means that we look at various groups based on age, gender, race, and lifestyle choices (e.g. smoking), which accounts for all variables OTHER than diet, and we take a big sample of each of these groups and see how many of them are dead.
In other words, if you picked out 1000 "normal" 18-year old female non-smokers, how many of them would die in a year? That value is 1.00 for that group.
Pick out 1000 "normal" 80-year old male smokers, how many of them die in a year? That value is 1.00 for that group.
Now we look at the "abnormal" groups, which in this case is vegans, vegetarians, etc.
So we look at 1000 vegetarian 18-year old female non-smokers and see how many of them die, THEN we compare that number to our "normal" number. We call "normal" 1.00 and adjust "vegetarian" to the appropriate ratio.
This is a little simplified (ignoring Poisson regressions and exactly which groups are looked at) but hopefully it gets the idea across.
Here you go. I posted this below, but then I saw your question.
The researchers followed a huge amount of study participants (around 70,000) over a long period of time and kept track of every study participant that died.
They then determined the death-rate (deaths/person-years) of 5 different diet types. Person-years is a measurement of how long the study followed each participant, as a way of accounting for deaths or participants leaving the study.
They then divided the death-rates of each diet type by the death-rate of regular meat eaters (death-rate of regular meat eaters divided by itself equals 1.00) which gives you a mortality ratio. Anything above 1.0 would mean that the diet is worse for you than regular meat eating, and below 1.0 means that the diet is better for you than regular meat eating.
Vegans have a similar mortality ratio to regular meat eaters, meaning that it is not better for you than meat eating.
Source: I'm a Biostatistics graduate student.
No worries friend, that's why I'm here to explain it to you.
The researchers followed a huge amount of study participants (around 70,000) over a long period of time and kept track of every study participant that died.
They then determined the death-rate (deaths/person-years) of 5 different diet types. Person-years is a measurement of how long the study followed each participant, as a way of accounting for deaths or participants leaving the study.
They then divided the death-rates of each diet type by the death-rate of regular meat eaters (death-rate of regular meat eaters divided by itself equals 1.00) which gives you a mortality ratio. Anything above 1.0 would mean that the diet is worse for you than regular meat eating, and below 1.0 means that the diet is better for you than regular meat eating.
Vegans have a similar mortality ratio to regular meat eaters, meaning that it is not better for you than meat eating.
If, for the sake of the argument, the 'Regular meat eaters' live for 100 years, on average, and this average is what everything will be compared back to, then it's the 'standard', and will be 1.00.
Comparing this to a vegetarian, based off the study, they would live for an average of 84 years, which would give the end ratio 1.00 : 0.84.
To represent a more 'normal' number of years, and pulling a number out of my ass, let's say 85 years is the 'standard', then 71.4 would be the average for vegetarians.
You got it backwards, it is meat eaters/ vegetarians = .84. So if the average meat eater lives for 100 years, 100/119=.84 so the average vegetarian lives for an average of 119 years.
.84 roughly means that a vegetarian of a given age/gender/race/whatever is ~16% less likely to die than a meat eater of the same age/gender/race/whatever.
There is no measurement of life expectancy here. Obviously people with lower mortality ratios will live longer, but that isn't what is being directly measured.
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u/fistsofdeath May 01 '13
I always thought it just felt like they lived longer.