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.