There is certainly lots of superstition in all of our beliefs, but you overblown your thesis to the point of being a bit ridiculous...
First of all you present it as "all or nothing" choice, like either you had full knowledge from a scientific study or otherwise there would be absolutely no reasons to choice one alternative over the other. In the absence of absolutely certain evidence there are still more or less "probably good" choices given the informations we have and there are also heuristics that might be helpful.
You also assume that the only way to navigate nutritional choices is through statistical studies. There are other ways though, we have a decent understanding of the physiology of the human body and its biochemistry and we happen to know for example that the moving of waste products through the intestines is greatly helped by fiber consumption, so I don't think eating green vegetables is particularly superstitious.
With your point about "purity" you wander into psychoanalysis, which is rather funny considering your supposedly hyper-rational stance.
BTW, what I like most about John Ioannidis's work is that he not only proved theoretically that most medical research is false, but he showed it empirically: He showed that a large percentage of papers in the best regarded medical journal turned out to either be completely false, or to have a much reduced effect-size. Some of these papers suggested practices that, at the time, were considered "probably good" choices, and have since been shown to be anything but.
What I was saying about purity had nothing to do with psychoanalysis. Not all psychology and anthropology is psychoanalysis, and I suggest you take a look at Haidt's research. At the very least, it's thought provoking.
Lastly, I'm not taking a hyper-rational stance. I've long ago realized that I, like all people, am far from rational. I am superstitious myself, and about stranger things than food. I just think that the rise of the food religion among the educated liberal elite is interesting. I am very much interested in the history of religion and mysticism, and I always find it fascinating how magic works its way back into our lives -- contrary to Max Weber's assertion -- no matter our background. Haidt's theory of values is one especially interesting framework through which to examine this phenomenon.
"Proved" is being thrown about a bit liberally in connection with Ioannidis' work. It's certainly in dispute [1]
Either way, it seems your central point has a number of flaws. What you are attributing to superstition (e.g. consuming more leafy greens) is in fact more often than not rational decision making based on admittedly limited information.
Will the consumption of vegetables ultimately improve ones health? I don't know, let's take a more specific example. For instance, take someone interested in positively affecting their likelihood of developing diabetes. A quick google search turns up a study that notes a correlation between increased vegetable intake and a reduced risk of diabetes[2].
Of course, increasing intake of green vegetables may mean a decrease in some other substance. Another quick search turns up a research study documenting a link between increased fructose consumption and insulin resistance [3]. Thus, if I were hypothetically interested in positively affecting my insulin response, it would be quite logical to increase my consumption of green vegetables while decreasing my intake of sugar.
Is this course of action wrong? Possibly. However, it's certainly rational and not exactly "superstitious". You've defined the term so loosely as to encapsulate even such things as making rational decisions based on limited information. That is certainly not what superstitious really means. Certainly, someone who refuses to change their dietary habits despite ample refuting evidence could be classified as superstitious, but that's not a distinction you have made.
[1] http://www.technologyreview.com/view/510126/the-statistical-...
[2] http://www.eurekalert.org/pub_releases/2010-08/bmj-glv081810...
Perhaps I have not made my case clearly. Magical thinking has two parts: the first is being wrong (although that's not essential for magical thinking; it can be accidentally true); the second -- and this is what distinguishes magical thinking and superstition from mere false belief -- is its motivation to action. People believe many things that are wrong, but superstition is the false belief that changes their behavior.
My claim is that healthy food falls under the category of superstition, or magical thinking, because people so readily turn what you call limited information into action. What we may think of as "classical superstition", say fear of black cats, was also based on limited information. I'm sure there was plenty of evidence to suggest black cats are harbingers of bad luck. So, fearing black cats could be classified as rational action.
But fear of black cats, same as the healthy-food religion, is superstition precisely because it is a belief people accept based on lower standards of evidence than they would in other aspects of their lives, and at the same time motivates them to take action. Why? Because they want to believe it. It makes them either afraid or hopeful.
There were university publications on black cats being harbingers of bad luck? While it's hard to juxtapose what constituted an 'equivalent' level evidence during what are otherwise radically different historical time periods, this claim strikes me as stretching the analogy quite far.
> But fear of black cats, same as the healthy-food religion, is superstition precisely because it is a belief people accept based on lower standards of evidence than they would in other aspects of their lives
Multiple academic findings corroborating each other is typically seen as enough evidence upon which to base action. If not, then what constitutes adequate evidence?
Also, it would be helpful if you could point out aspects of peoples lives in which they generally behave according to your definition of rationality, or in which they maintain a 'high' standard of evidence.
There is little of that in nutritional research.
> Also, it would be helpful if you could point out aspects of peoples lives in which they generally behave according to your definition of rationality, or in which they maintain a 'high' standard of evidence.
I'll try, but first I'd like to point out that I don't think there's hardly any important decision people make rationally. I personally believe that people are utterly incapable of rational thought in all but the most emotionally-neutral of situations (and even when they are somehow able to think rationally, they are often unable to follow through with action), but that is a little beside the point.
People require an impossibly rigorous proof to sway their political opinions (you can call it the opposite kind of superstition. If healthy food is a new cult, politics is like an old, established religion).
Also economics and finance. Economics is also a highly debated field with about as much scientific rigor as nutritional research in its current form, and yet most people are much more careful about changing their spending habits -- or the economic policy they support, which brings us back to politics -- and certainly much less radically than their eating habits. Again, this may be superstition that causes inaction rather than action, but I think it's qualitatively different from our food superstition.
Raising children, too, I think, is different. I can't quite compare it to food (I haven't had the time to think it), but while there are many child-rearing fads, they somehow "feel" different from food fads. They feel more like fads, while healthy eating feels more like religion.
Sorry for not being very rigorous myself, but I'm just raising some things we can think about.
I think you're too loosely using the terms "superstition" and "magic".
This is Merriam-Webster's definition of superstition: 1 a : a belief or practice resulting from ignorance, fear of the unknown, trust in magic or chance, or a false conception of causation b : an irrational abject attitude of mind toward the supernatural, nature, or God resulting from superstition 2 : a notion maintained despite evidence to the contrary
There are indeed diets that are superstitiously motivated (don't eat pork because it's an impure animal, don't eat cows cause they're sacred, etc), but you're throwing everything in the same pot, liking religious motives and decisions by rational minds to eat or omit certain food items, based on observations and deductions (albeit sometimes limited and flawed) of effect and causality. If anything, the latter is but an attempt at building a framework toward a saner nutrition.
If we were to listen to you, we should wait until everything has been discovered about food and physiology to start making up our minds as to what is good or bad to ingest. At which point I guess what you keep calling "magic" then becomes science. This tendency of wanting to be absolute is a bit naive. No body of knowledge works like that. Just because our understanding of a topic is patchy, doesn't exempt some connections to be made that can be built upon to stitch up a gradual and more complete understanding. Which, if I observe how nutrition has evolved, is exactly what's happening.
Nothing magic there.
If, say, it's 80% (rather than 95%) likely that eating more than 4 servings of fruits and vegetables per day helps reduce your chance of having cardiovascular diseases by 35%, and you don't mind the food group anyway, why shouldn't you try?
In any case, there are very few (or no?) studies that say eating a lot of vegetables and fruits (within reason) will cause you health problems.
A principle of entrepreneurship is that whenever a bet yields either positive or neutral results, you should do it. Why shouldn't this principle be applied to such an important area as our health and wellness?
Is salt bad for you? (hint: unless you have a very specific hypertension condition, all the bad things you heard about salt are not relevant to you)
How much is too many eggs per day? (hint: no known limit. Cholesterol from eggs was never shown to be a problem)
Well, how about butter and fat? (hint: right kind of butter is good for you, as is the right kind of fat)
But surely, saturated fat is bad for you! (hint: no proof of that)
But at least bacteria and dirt are bad for you, I'm sure of that! (hint: life span is correlated with eating lots of fermented - i.e. bacteria laden foods. Also, people who work in sewage have higher life span and less illness overall)
You are taking tens or even thousands of bets based on bogus research without even knowing that. It is not unreasonable to assume that washing your hands all the time and keeping your house clean significantly raises the probability of autoimmune disease.
And really, if you go through nutrition literature and try to trace the knowledge to repeatable and demonstrable experiments, you'd agree with "very little". e.g., the calorie marking system used on foods is based on bomb calorimeter experiments (which you can debunk at home) and atwater factors (which have been shown to be grossly inaccurate, as in tens to hundreds of percents).
It's best to assume all nutritional claims are bogus, because the vast majority of them probably are, and there is no way for us to tell which at this point.
Cholesterol is ultimately used (and therefore made) by the body in an attempt to heal conditions that cause heart disease (The main use is for making vitamin D, whose other ingredient -- sunlight -- is in short supply for most people in the western civilization).
Thus, cholesterol is a good marker for pending problems, but is not itself the problem.
Analogy: People who take an advil are likely to report a headache 1 minute after taking it. Therefore, seeing someone take an advil is a good indication for a headache. But it is not the cause of the headache - and in fact, banishing all advil will not make anything better. But somehow, people think that banishing cholesterol will -- despite evidence to the contrary.
(Yes, statins do decrease heart disease, but they increase all cause mortality. And there have so far been many cholesterol-decreasing drugs developed - but none other than statins have decreased heart disease)
"I don't know anything about ____. Therefore all these claims the so-called experts are making about ____ are clearly bogus!" This kind of dismissive line of thought (there are some variations on the theme - many people don't like to admit that they don't know something) pops up in a lot of areas and it is pretty embarrassing.
In the real world when I meet people with attitudes like this, it invariably says a lot more about the person than the supposed inscrutability of the topic under discussion. The narcissism to dismiss entire lines of study and the lack of curiousness of someone who hasn't bothered to form an opinion on which ideas are better than the others... even when you hang out with a community of avowed skeptics, these attitudes really help separate the wheat from the chaff.
He doesn't advocate that we give up, crawl into the fetal position, and stop trying to understand the world any more than any of the other popular statistics skeptics do.
I maintain that there's a meaningful difference between "often wrong" and "almost all" wrong and "assume all claims are bogus" and "view claims skeptically." One approach is a license to intellectual laziness (defeatist) and the other requires effort but can reap benefits.
I agree with you that a lot of our diets (especially fad diets) are based on little to no science. At best, they're based on incomplete science. But what dietary guidelines would you recommend to someone?
Personally, I try to follow Michael Pollen's advice (Eat food. Not too much. Mostly plants.), whether or not it's based in complete science. Because with diet, one can't simply wait for science to settle things out.
Cutting too much on salt is indeed harmful http://en.wikipedia.org/wiki/Hyponatremia - up until 30 years ago or so, hyponatremia because of too little salt intake was virtually unheard of in the west, and now it is rare but not unheard of, because some people take the "cut back on salt" recommendations seriously.
What's the harm in eating only bland food? No harm. Also no harm in cutting back on listening to your favorite music. But why on earth would you do that? It's no different than avoiding alcohol or pork for religious reasons, or not driving on a saturday for the same religious reasons. If you like it, no one is stopping you. But it is based on blind faith, rather than science.
> But what dietary guidelines would you recommend to someone?
I was going to quote Pollen, but you beat me to it :) I think another recommendation from Pollen is helpful: "Do not eat anything that your grand-grandmother wouldn't have recognized as food".
Personally, given that I've found so much evidence that the "common knowledge" is wrong, I look at the fringes hoping to find something more useful. To that end, I recommend following the blogs (and mostly, but not exactly, the advice) of Dave Asprey (Bulletproof Executive) Tim Ferris (4 Hour Body) Paul Jaminet, Gary Taubes, Stephan Guyonet, Mark Sisson ... start browsing any of them and you'll find the others.
Now, I'm not saying you should or shouldn't do one thing or another when it comes to nutrition. All I'm saying is you should be aware that it's little more than superstition and magical thinking. It's very hard to resist magical thinking, but it's often good to know when you're doing it. Sometimes doing things with your eyes open is better than doing them with your eyes shut. Although in this case I'm not 100% sure about that: there's clearly a lot of (positive) placebo effect at the cause of many anecdotal reports about nutrition, and knowing that it's mostly superstition may negate it.
Why would modern fruit contain "more sugar"? More sugar than when? How much more sugar? Who miraculously put the extra sugar in the fruit? The fact is, even if we selectively bred fruit to be sweeter, we're not going to get it much sweeter than it already was. Nobody's going around injecting apples with extra fructose with a syringe.
Getting all your vitamins from meat is ridiculously inefficient; you can do it, but you're creating a tremendous ecological burden. All of that meat has to be raised, fed, watered, and pastured. Fruits and vegetables cut out the middle man; they use much less water and land to get the same nutrients into your body.
It's fine to say that 'magical thinking' is bad, but you're not doing any better. If anything you're ignoring facts based science in favour of 'what some people say'.
Selective breeding, of course. Modern vegetables are, in general, less bitter than in earlier times. Fruits are often sweeter---and easier to farm industrially and bring to market. Also, we live off less different kinds of fruit and vegetables than in earlier times. There used to be hundreds of different apples in widespread use for examples.
Not saying that it's necessarily bad. Just that pron's hypothetical argument isn't actually all that hypothetical.
That does not necessarily mean more sugar - it just means less bitter. (These axes are independent).
Selective breeding puts pressure on easy-to-grow-and-sell (shelf life, size, shape, resistance to pests) and only afterwards on flavor.
And another important (and often forgotten) point about modern frutis and vegetables is that they are mostly picked when green (when not all sugar has ripened yet), and then chemically ripened in a process that does not yield as much sugar as natural ripening.
I would like a reference before I believe that today's fruits and vegetable contain more sugar than those of 50 years ago.
And regarding "Getting all your vitamins from meat is ridiculously inefficient" -- you are trying to hack the unhackable, speaking in scientific terms about things we have little clear scientific understanding of. "Fruits and vegetables cut out the middle man; they use much less water and land to get the same nutrients into your body." -- Nope; you don't know that. Some people believe that, some don't.
For all we know, such careful nutritional hacking has little, if any, effect on our health. That's what we know. What people believe is a whole other matter. Most of the diet-talk we hear is just catechism of a new religion (and there's nothing inherently wrong with that, except that pseudoscience is a little annoying) and a whole lotta politics (in this case, it's fascinating to see liberals defending pseudoscience, while conservatives discard it, maybe because they believe the liberals who believe it's actual science). Science it ain't.
Is there?
As far as I know, there is evidence about sugar but not about fruit. And assuming that evidence about sugar translates to evidence about fruit is exactly the kind of sin your first post talks about.
(But if you can point me to experimental evidence specifically about fruit, I'd be very interested in reading that)
However, that does not at all address the question of whether or not they are healthy for you or not.
Fructose on its own is associated with all kinds of problems. But a fruit is not fructose on its own, and it's possible that other things in fruit make fructose "not a problem".
e.g.: Table sugar is 50% fructose - however, it is not associated with the same kind of problems that pure fructose is associated with.
e.g.: Table salt, Sodium Chloride, is harmless (actually, essential) in small amounts - however, just the same amount of chlorine (if you managed to take the sodium away somehow) will easily kill you. And I don't know, but I'm sure pure sodium if ingested wouldn't be health for you either.
So, the question stands: Is there evidence that fruit is bad for you? Even suggestive evidence? A study of comparable populations whose main difference is the amount of fruit eaten, which shows that the less-fruit-eating population is better off?
First about the salt - NaCl is salt so it is chemically quite inert you will have hard time breaking it unless you pump quite a lot of energy (or use elements that are more chemically active than either Na or Cl and there aren't many (lithium, fluorine, hydrogen).
Chlorine is very potent oxidizer that will wreak havoc in all kind of processes.
Sodium will just try to make your intestines into soap - quite unpleasant thing.
But they are chemically different elements.
Fruits are not bad for you in the same way most of the food is not bad for a healthy person. But if you are a person with the metabolic syndrome, high insulin resistance or type 2 diabetes you just cannot assume that a diet of only bananas, ultra sweet apples, pomelo, peaches etc will do you much good.
Of course fruits have the benefit of containing lots of water and pulp so they are digested slower than a can of coke with the same sugar amount which is good.
If you are healthy person eat fruits freely. If you are not be careful with the blind assumptions that they are good for you. Ask someone with great knowledge about human metabolism specifically for your case.
> the difference between wild apples, cherries and strawberries and the ones you can buy in the supermarket.
Anecdotal, of course, but while I haven't had a chance to pick wild apples or cherries, I did have a chance to pick wile strawberries, raspberries and blackberries - and they were just as sweet and perhaps even sweeter than those I buy at the supermarket. They _were_ much smaller and not as nice looking, but were extremely sweet. Similarly for grapes.
I know for sure that e.g. industrially grown tomatoes have been optimized for size and looks at the EXPENSE of sugar (and other nutriet) content. This might also be true for other fruits and vegetables.
> NaCl is salt so it is chemically quite inert
That's exactly my point. It's possible that fruit is "inert" in its sugar effect - studies about pure fructose consumption are potentially irrelevant.
> But if you are a person with the metabolic syndrome, high insulin resistance or type 2 diabetes you just cannot assume that a diet of only bananas, ultra sweet apples, pomelo, peaches etc will do you much good.
Of course, but that's begging the question. If you are a person who suffers from hypertension, than you cannot assume that regular salt intake is good for you! But it is, for 80% of the cases - the remaining 20% being the salt-sensitive hypertension people.
You cannot assume that such a fruit diet will do much bad either. Doing so is blind faith. And that's exactly pron's point.
> Ask someone with great knowledge about human metabolism specifically for your case.
I've been looking for someone like that, but it seems that there are non to be found. Specifically, everything about my metabolism falls outside accepted wisdom; You'd expect the experts to want to look at evidence contradicting their predictions to learn to improve their predictions - but after talking to 30 or so "experts", I have not found one who has such an interest.
So, yes, it's probably lethal.
Table sugar consumption is indeed bad for you only because of its 50% of fructose.
A random google search (e.g. see http://www.lef.org/magazine/mag2011/jan2011_Glucose-The-Sile... ) indicates that this belief is not part of the consensus. Care to back that up?
If there is actual evidence, please cite it. I've never heard fruit proclaimed as bad for you. In fact, every major healthly eating initiative or campiagn (whether from governments, the World Health Organisation, or NGOs) always recommend consuming more fruit and vegetables as part of a healthy diet.
The fructose in fruit is not the same as high fructose corn syrup found in many processed foods. Yes, fruit can contribute to acid erosion on teeth, but this is also dependent on the type of fruit, the quantity you eat and when you eat it (e.g. eating fruit with a meal can lessen the impact of the sugar). Eating fresh fruit is always preferable to dried fruit or fruit juices.
Here's an interview with a UCSF professor who claims fructose in all its forms is a problem: http://www.sciencefriday.com/segment/01/11/2013/the-fallacie...
Also http://www.sciencefriday.com/segment/01/11/2013/the-fallacie...
http://www.crsociety.org/index.php?/topic/291-dr-lustig-on-f...
"I think that fruit is so much better a choice than virtually anything else in the store -- particularly any processed food -- that I don't want to come down on it. But I would say, fruit is one of those things where I would say, everything in moderation."
This sort of falls into the "duh" category. Just as a sensible person wouldn't consume a ton of saturated fats in the name of eating a high protein diet, a sensible person is not going to be eating 20 bananas and five pounds of strawberries a day in the name of getting enough fruit.
As for the professor's claim that exercise isn't effective for weight loss, I think laypeople should be aware of the tendency for academics to speak in macro terms. The vast majority of people I have met who are overweight and have tried unsuccessfully to lose weight a) do not have as healthy a diet as they believe they do (far too many processed foods) and b) if they exercise and exercise consistently (a big if), do not exercise long enough and intensely enough to burn fat and become conditioned.
Anecdotal? Yes, but instead of blaming specific foods and claiming that exercise isn't effective, let's just be honest: most people won't lose weight because they can't commit to major changes in their lifestyle.
What is a "healthy diet"? I don't believe there's a one-size-fits-all answer, but I mentioned processed foods because at the highest level, there is plenty of evidence that processed foods are problematic when consumed in the quantities they are being consumed in:
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2897733/ http://news.yale.edu/2013/03/06/yale-researchers-identify-sa... http://www.biomedcentral.com/1741-7015/11/63 http://www.diabetes.org/news-research/research/access-diabet... http://jn.nutrition.org/content/139/10/1950 http://wholegrainscouncil.org/whole-grains-101/health-studie... http://www.sciencedaily.com/releases/2012/02/120210110038.ht...
> A principle of entrepreneurship is that whenever a bet yields either positive or neutral results, you should do it. Why shouldn't this principle be applied to such an important area as our health and wellness?
It's not only positive or negative expected value, but rather that the uncertainty (i.e. variance) outweighs the expected value of almost all detailed propositions.
After you took care of the simple and uncontroversial things, e.g. adequate amount of calories, enough iron etc, there's not too much we know how to optimize in general.
http://www.psychologytoday.com/blog/naughty-nutrition/201201...
"[...] environmental toxicity and genetic proclivities would have contributed as well. Certainly, Jobs was exposed over the years to massive bombardment from WiFi and other electromagnetic fields (EMFs)."
Digging deeper, it appears her career as an author and nutritionist is based on the idea that eating soy and vegetarianism is bad for you. Correlation is not causation, but it has long been known that vegetarians live longer.
I'll put more faith in peer-reviewed scientific journals than an author who writes in a magazine called "Psychology Today."
Until science catches up, I think we should all "try and see", compare notes, and keeping searching until we find solutions. I've been patient advocate for many others; this is old advice.
---
About two years ago I tried the Four Hour Body strategy. My goal was to lose weight. I was astonished when my psoriasis started to clear up. The important part: I established cause and effort by stopping the nutrition (bad eating during business trips) and the psoriasis comes back with a vengeance. I have no idea why it works. Because I'm eating more veggies? Because I'm avoiding wheat? All I know is it works.
Since then, I've had steady improvement while sticking to the troglodiet (tm), resumed eating meat and lotsa more of veggies. More or less following Dr Terry Wahls "Minding your Mitochondria" strategy, with occasional treats (cheesecake!) so I don't go insane.
Most recently, my gf persuaded me to try her naturopath doctor. From prior experience, I think naturopaths are quacks at best. But I also think that the good bits of naturopathy will eventually just be called "nutrition".
I presented specific complaints to this ND, which my other doctors haven't been able to assist with. I'll give an non-embarrassing example. My muscles never relax. I'm now super tone without exercising. It's fantastic. But I also have zero energy. I've been taking magnesium. I've seen a neurologist. I've tried some other stuff.
So the ND says the magnesium isn't getting to my muscles because I'm not eating enough essential fatty acids. Tells me to eat more of such and such and take some pills. Sure, why not, can't hurt.
Similar story for the other conditions I have.
Well, I'm about a month into this new regiment. Huge improvement on one issue, modest improvement on two others, and no change with the fourth.
In a few more months, I'll stop the regiment, see if my conditions get worse. I don't want to be taking pills and such without benefit.
---
I agree with everything you've written, but we should continue to experiment and ask questions, until we find solutions.
That said, I suppose I could make the same argument that many people with a certain political leaning do engage in self-mandated food purity by eating vegetarian or vegan. Which sound reasons and very little magical thinking in terms of the economics of food.
First, there isn't much logical thinking involved in veganism or vegetarianism. At their best, they're about ethics (which I certainly respect). At their worst, they make some very dubious claims about te economics of food and the environment.
But either way, note that people make significant and probably burdensome changes to their lives when it comes to upholding morals pertaining to food. I think that more (liberal) people would go a longer way making actual life changes when it comes to food than just about anything else. They might explain that the things you actually put into your body are the things you should care about most. Only there's little evidence to suggest that's the case. It is much more probable that national policies like increasing minimum wage or reforming education would have a bigger (though indirect) effect on your personal well being than optimizing your diet (as long as it's more or less "normal").
All religions, in this case the healthy diet religion, must not rely on facts in order to gain followers; they must rely on gut feelings, because gut feelings are much more powerful than proof when it comes to motivating life changes. And we just naturally feel that ingested food has to have a major effect on our health and general well being. It just makes sense, right? But, at least in the current state of scientific knowledge on the subject, that intuition is just superstition. After decades of research there's little consensus even on what makes us fat, let alone more subtle or indirect effects diet may have on our health. In fact, it's very probable that even if one day we do know exactly what's healthy to eat and what isn't, and at what quantities, the actual effect-size on our health will be quite small. It's quite possible that within some sane bounds, what food we eat simply does not determine our health to any large degree.
Here is an example comparing the amount of water needed to irrigate various crops compared to the amount needed to raise beef.
US Corn Production: 9 gallons water / lb corn
US Wheat Production: 14 gallons water / lb wheat
US Barley Production: 26 gallons water / lb barley
US Alfalfa Production: 31 gallons water / lb alfalfa
US Beef Production: 441 gallons water / lb beef
http://www.journalofanimalscience.org/content/71/4/818.full....
Global Spinach Production: 2 gallons water / lb spinach
Global Potato Production: 4 gallons water / lb potatos
Global Banana Production: 13 gallons water / lb bananas
Global Apple Production: 18 gallons water / lb apples
Global Lentil Production: 64 gallons water / lb lentils
Global Cashew Production: 121 gallons water / lb cashews
Global Almond Production: 252 gallons water / lb almonds
http://www.waterfootprint.org/Reports/Mekonnen-Hoekstra-2011...
I could look for more examples, but this took me about half an hour already, and I think it pains a rather compelling picture by itself. The difference would be less extreme when looking at pork and poultry, but there is still a stark contrast.
But the whole point of this thread seems to be that such an analysis is hard to do.
There are so many confounding variables here that it's really hard to tell. Everyone pretty much chooses to believe whatever data they like best. For example, cultivated land is probably less environmentally friendly than pasture land.
If x = environmental impact of cultivating crops
then R*x = environmental impact of raising livestock
where R = pounds of feed required to produce one pound of meat
Now if we raised our meat differently, such as only on grass-fed pastures, then things might look a lot different. But in the US at least, factory farming and animal feed is the norm.
Moreover, it's quite conceivable (again, no proof, but there's little proof af anything in this field) that herbivores would convert one pound of corn much more efficiently than we would. This might mean that humans are better off wasting energy by feeding vegetables to animals and then eating the animals, than eating the vegetables directly. Maybe we can't extract the nutrients from the vegetables as well as herbivores do, so that seemingly wasted energy is actually a net gain.
Consuming plants is not as efficient as photosynthesizing, and consuming animals is not as efficient as consuming plants.
In this case, the cows burn energy from the food they consume for as long as they're alive, meaning it's a physical impossibility for the meat produced from them to contain as much energy as the food they consumed.
Unless you're claiming that raising livestock violates the laws of physics, but that's an entirely different argument.
Giving an incredibly quick example, wheat and ground beef have roughly the same caloric density
Wheat: http://www.fatsecret.com/calories-nutrition/usda/whole-grain...
Beef: http://www.fatsecret.com/calories-nutrition/usda/ground-beef...
But since it requires numerous pounds of wheat to create one pound of beef, you are losing overall caloric density.
http://www.fatsecret.com/calories-nutrition/kroger/gummi-bea... https://www.google.ca/search?q=40g*11.3+to+lb https://www.google.ca/search?q=140*11.3
First, there isn't much logical thinking involved in veganism or vegetarianism.
(There are few things as useless as discussions about nutrition at Hacker News.)
Of course it's ok, and in a lot of cases, preferable, to not behave logically.
I don't eat mashed potatoes, but it's not because of some reverence for the humble potato or concern about industrialization of farming, it's just because I don't like the taste.
It's absolutely possible that many vegans are vegans due to some psychological pressure towards purity or ascetism, and they just coincidentally chose a pressure vent that also makes sense in an economic and environmental sense. I'm sure many of them might even be aware of that dualism.
Actually, the warp-drive/teleportation problems might be easier, because we'll probably know when we get there. With nutrition, there's little evidence to suggest that a theoretically perfect nutrition would result in much improved health over sub-par nutrition. We don't even know that nutrition has a strong effect on health at all (other than eating poison, or few other truly well-known facts).
[1]: http://webadventures.at/2007/06/17/der-mensch-als-industriep...
This is what we call progress. Technology doesn't grow on its own, it embodies the deep insights into workings of reality humans gain throughout the century. Therefore it is to be expected that we will draw parallels and that they will improve as we improve our tech.
When John Ioannidis proved that most published medical research is false[1], he singled out genetics and nutrition[2] as the two most problematic fields, where very, very few findings are true. The fact is that we know alarmingly little about what constitutes a healthy diet. Let me clarify: we know hardly anything about significant difference in total health one relatively "normal" diet has over another. Ioannidis's advice: completely ignore any nutritional "scientific" claims because they are anything but. Any supposed claims for "healthy" eating are no more than wishful thinking, pseudoscience and good-old snake-oil salesmanship.
What is interesting from a scientific point of view, and this is one subject we know a lot more about than actual nutrition, is why people who are otherwise scientific minded skeptics are superstitious when it comes to nutrition (if you believe that eating more green vegetable or less, consuming more vitamin C or less, more saturated fat or less is actually better for you, then you are superstitious, unless you are knowingly placing a scientifically unfounded bet on one diet over another).
Obviously, the well-known psychology of magical thinking applies to everyone, and even skeptics are not immune to it (Charles Darwin, if one anecdote about him is correct, quite amazingly identified the effect magical thinking had on his own research, and took measures to counteract it). But why is food such a focus of superstition among skeptics? It probably has to do with their political leaning.
Jonathan Haidt hypothesizes that the value of "purity" is ingrained in human existence, and every society seeks to fill it with particular meaning[3]. Because liberals wholly reject giving "purity" sexual or racial content, they choose to purify themselves through health, and in particular, food. It seems that people have such a strong desire to feel pure, that those that cannot achieve it through religious means, try to achieve it with food. And because food is, after all, subject to scientific study (though mostly bogus), it gives that little something to grab onto and construct magical thinking around.
Consider this if you don't believe me: pick one scientific nutritional finding that you particularly like, and have chosen to adhere to. Let's suppose that the finding is true as published. Now, look at what statistical effect-size that particular research claims your chosen diet has. For example, by how much does it prolong life? 10%? 5%? 3%? Or by how much does it reduce the risk of getting a particular form of cancer? Does it take it from 1/100 to 1/10000? Or, perhaps, from 1/1000 to 1/1200?
Now think if in other areas of life, such effect-sizes would change your behavior as much.
Theres definitely a lot of psychology when it comes to people's diets. Science? Not so much.
[1] http://www.plosmedicine.org/article/info:doi/10.1371/journal...
[2] http://www.theatlantic.com/magazine/archive/2010/11/lies-dam...
[3] http://www.ted.com/talks/jonathan_haidt_on_the_moral_mind.ht...