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Comment by nopinsight | Hacker News Reader

What counts as scientific evidence has fairly high standard. What we know may not reach that level of rigor, but isn't it still a bit more than 'very little'.

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?

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When it's a neutral thing for you, sure, why not. However, most things about nutrition are NOT neutral.

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).

Right on. In fact, I think there's little conclusive evidence linking dietary (ingested) cholesterol to heart disease (though, if I'm not mistaken, there is some/strong? evidence linking blood cholesterol to heart disease).

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.

> , if I'm not mistaken, there is some/strong? evidence linking blood cholesterol to heart disease

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)

> 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.

"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.

That's nice. Read the thread. TL;DR: It's been proven (though some dispute it) that almost all nutritional research is false. That research's validity is pretty close to that of homeopathy.

It's peculiar that you cite Ioannidis's work as having "proven" your utterly defeatist position. Your point is that there's no way anything could be learned with nutrition studies, his point is that there's very much a correct way to learn things with nutrition studies and a method for evaluating the quality of such studies to make sure they're doing it right.

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.

Neither does prom advocate that. He just said existing research is mostly wrong. That's not defeatist, that's realist.

That's not actually what he said.

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.

It sounds like you're suggesting that people eat as much salt as they like. Where's the harm in cutting back on the salt?

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.

> It sounds like you're suggesting that people eat as much salt as they like. Where's the harm in cutting back on the salt?

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.

There's actually evidence to support that eating fruit is quite detrimental to your health, as modern fruit contain so much sugar. What are you eating fruits for? Water? Vitamins you can get from meat anyway? A lot of people say fruits are bad for you.

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.

> There's actually evidence to support that eating fruit is quite detrimental to your health, as modern fruit contain so much sugar. What are you eating fruits for? Water? Vitamins you can get from meat anyway? A lot of people say fruits are bad for you.

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)

Current fruits are with much higher sugar content than in generations past. So you are pumping yourself with fructose much faster.

I suppose that might be true (though I don't assume that -- references will be appreciated).

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?

Anecdotal evidence how sweet current fruits are - the difference between wild apples, cherries and strawberries and the ones you can buy in the supermarket.

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.

I appreciate your answer, but I feel the need to point out that the original question still stands unanswered. Is there any evidence, weak as it may be, that FRUIT consumption is harmful in any way? (note: not that FRUCTOSE consumption is harmful. I'm aware of that. I'm looking specifically for FRUIT consumption).

> 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.

Pure sodium is an extremely reactive metal. It's so reactive that it doesn't occur in nature - for example, if you drop it in water, it'll explode. (http://www.youtube.com/watch?v=ODf_sPexS2Q)

So, yes, it's probably lethal.

This line of discussion rather proves the original point. We don't know if unbounded fruit consumption is bad. Of course unbounded simple sugar consumption is (we think) but some evidence has shown that for whatever reason, sugars directly from fruit enter the blood stream slower. Maybe. :-)

> e.g.: Table sugar is 50% fructose - however, it is not associated with the same kind of problems that pure fructose is associated with.

Table sugar consumption is indeed bad for you only because of its 50% of fructose.

So, you claim that pure glucose has no known health problems associated with it? (If I understand correctly this is an equivalent claim to what you say, since the other 50% is glucose).

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?

"There's actually evidence to support that eating fruit is quite detrimental to your health.."

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.

Do you have any evidence for your claim that fructose in fruit is different from fructose in corn? Absent such evidence, you're just repeating the same magical nutrition claims this thread is about, and name dropping the WHO does nothing to change that.

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...

Please note that while Professor Lustig's claims about the wholly toxic nature of fructose are not accepted as fact (see http://www.ncbi.nlm.nih.gov/pubmed/20047139 and http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3411192/ for a couple of examples), I think you're still miscategorizing his claims. Please see:

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.

I think it's funny that you're citing all of these studies and generally being evidence-based and rational and then you casually mention that "processed food" makes people fat.

Well this whole discussion, especially debunking citations with citations, pretty much is a big evidence in favour of the original thesis - we don't know for sure pretty much anything about nutrition.

I didn't write that. I wrote that in my own experience, most of the people who are overweight who try unsuccessfully to lose weight a) don't have as healthy a diet as they'd like to believe and b) don't exercise long enough and intensely enough if they work out at all.

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...

OK, this is a pretty ridiculous claim. Other people have already pointed out, "There's actually evidence" requires some evidence. You have none.

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'.

Ok, I wasn't not trying to insult fruit or anything, and I was referring to research about sugar, which some other commenters are debating. Just saying that it's not even clear cut that eating fruits is particularly healthful.

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.

As I understand it, fructose in fruit tends to be offset by the fact that fruits have fibre. The fibre means the fructose is kept in your gut for longer, and bacteria there break it down before it has a chance to hit your liver. The issue with fructose/sucrose tends to arise when we have it in liquid format (juices, soft drinks etc.), or eat large quantities of foods high in sugar without the accompanying fibre.

> Why would modern fruit contain "more sugar"? More sugar than when? How much more sugar? Who miraculously put the extra sugar in the fruit?

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.

> Modern vegetables are, in general, less bitter than in earlier times.

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.

Oh, sure, wasn't meant as a reference, but just some evidence that it's not totally implausible.

This is very loose wording. "Evidence" this is not. It is an argument supporting an idea, which is still therefore hypothetical.

A few broad facts are well known, but our knowledge is still quite limited.

> 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.

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