My coworkers & I watched a video over lunch about the dangers of eating meat, which prompted discussions about the validity of the arguments for or against meat eating.
I won't reject the hypothesis that modern north american eating habits lead to an early death - quite the opposite, actually. But as one of my colleagues pointed out, life expectancy isn't the only factor to consider in lifestyle decisions. We have to consider quality of life too (ie. enjoy eating lotsa meat).
Enter the QALY. Quality Adjusted Life Year. It's the metric used by Cost-Benefit / Cost-Effectiveness studies of Drugs. A QALY is the product of life expectancy and quality of life. Obviously, quality of life is subjective, so we try to quantify quality of life through surveys (also quantifiable events such as the number of hospitalizations or amount of time spent in a hospital).
So, for example, if you really enjoy smoking and on a scale from 1-10, life with smoking is a 9 and life without smoking is an 7, that's a 20% difference in subjective quality of life [(9-7)/10]. So, how many years does smoking knock off your life expectancy? If it's anything more than 20%, then it's better to quit smoking, because the net QALYs will be less if you smoke than if you don't.
Okay, so what if smoking knocks less than 20% off the end of your life? Well, you have to consider other health effects that will affect your quality of life later on. For example, if you end up with lung cancer, and need to undergo surgery, your quality of life will suck for that duration of time, and for a good period of time after. I mean, your QALYs during chemotherapy will be negligible - you may as well be dead for that period of time. In fact, your QALYs for the remainder of your life will probably be less than if you never had lung cancer at all.
It's quite clear from what we know about smoking that smokers will on average have less QALYs than non-smokers. That is to say, the cost of smoking outweighs the benefits.
Let's take that model and apply it to meat.
Do vegetarians and/or vegans live longer than meat eaters? Anecdotal evidence (for what it's worth) seems to indicate this may be true.
Do people on the atkins diet suffer from poor cardiovascular health and shortened life spans? Again, anecdotal evidence points to some very serious side effects of the atkins diet - case in point: how did Dr. Atkins die, and at what age?
How much will you miss meat? This is the really subjective one that will differ for each person. As in the case of smoking, this is difficult to rate until you've actually tried the lifestyle change.
How will poor cardiovascular health affect overall quality of life?
How will diabetes? A heart attack? A stroke? How does being morbidly obese factor into your enjoyment of life?
Food for thought.
-d
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7 comments:
It's hard to live by the QALY score...it assumes you know what will happen to you in terms of your life expectancy and health.
What if "Bob" avoided eating meat to boost his QALY score and then gets hit by a bus when he's 35? Screwed! :(
You gotta remember that there are two words in "life expectancy." Together, it means how long you expect to live. You don't expect to get hit by a bus. You expect to live to a ripe old age.
I would say that our average life expectancy statistics already take into account the bus factor.
It doesn't make sense to "live each day as if it were your last" because you'll be financially, and other kinds of screwed when you're 90.
-d
I think everything just has to be done in moderation. Diet and exercise = long life (unless you have genetic problems or get cancer etc). I mean i love meat but i wouldnt want to just eat meat, and as for exercise over exercising during crucial growth periods actually hinders your growth and can cause muscle and bone problems (at least in dogs, i assume the same is true for humans). But the bottom line is i will take a few years off my total life expectancy if i get to eat giant chunks of meat from time to time, besides i plan to live till 96.
Right, but I'm really starting to question what 'moderation' means, and if it's actually a healthy thing.
Is heroin use in moderation okay? No, obviously not. What about smoking? No, not okay in moderation, but maybe okay on occasion. Alcohol? Apparently okay in moderation.
Now, what about meat? Is it really okay in moderation, and what defines moderate consumption? We know from the prevalence of heart disease and obesity that the population is consuming meat at an excessively high rate.
Are rates of cancer linked to meat eating? Colon cancer, probably. Now what about cancers where hormones play a big role, like breast cancer?
What I'm getting at is that our idea of moderation and a 'healthy' diet is somewhat skewed, and really not based on any hard science.
-d
"So, for example, if you really enjoy smoking and on a scale from 1-10, life with smoking is a 9 and life without smoking is an 7,"
Hang on, lets calibrate that a bit.
10: healthy and full use of limbs and senses.
7: amputation below the knee
6.7: deaf.
Where would you put "life without smoking" on that scale? Bear in mind a heavy smoker loses ~15 years of life expectancy, so 'smoking' should start off close to two points below 'not smoking' before you factor in enjoyment.
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