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Comment by epistasis | Hacker News Reader

This shouldn't surprise anyone...

People need to realize that research publications are not textbooks. They are communications to other researchers about the way that the evidence is pointing, that helps them design new experiments, that justifies expensive and spendy clinical trials, which eventually find conclusive evidence.

The idea that one can open a science journal and find interpretable truth revealed is a pernicious one. Trust that the data is true, but do not trust the models or the conclusions. Everything is in flux, and it's science because we likely don't know what the real world is like yet.

History will go back and pick out the key experiments and construct a path of discovery, but in real time almost nobody knows what the most important experiments truly are.

This makes for difficult journalism, but one should remain true to the physical world rather than the narratives that are easy to squeeze into 500 word news blurbs.

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It's not just that. There's a huge problem with selective bias here. People think that "healthy foods" automatically means good health, and bad health is automatically a result of processed foods, "bad health habits", etc. Bad health is your own damn fault for profoundly insulting mother nature by feeding your body Kraft Diner a few too many times.

News at 11: cancer is a natural occurrence. You could exclusively eat prime quality fish, raw organic fruits and veggies and still get a heart attack at 52 and cancer at 58. In other news, I seriously question the idea that paleolithic humans had incredible food wisdom and perfect health. They probably ate whatever the hell they could find at a given time of the year in their immediate environment, and that was probably hugely lacking in nutritional value when it's the winter, all the plants are dead and most animals hibernating.

I agree that making an effort to eat well is a good idea, but it doesn't make you immune to diseases, and diseases are not necessarily a result of bad habits. There is also a huge amount of conflicting information as to what is healthy food.

"News at 11: cancer is a natural occurrence."

So what? Something being "natural" has no bearing on whether it is favorable or preventable.

"You could exclusively eat prime quality fish, raw organic fruits and veggies and still get a heart attack at 52 and cancer at 58."

Of course it's possible. But if you had any amount of sense, you wouldn't be making conclusions from a single case.

"In other news, I seriously question the idea that paleolithic humans had incredible food wisdom and perfect health."

Who's making that claim? The claim most paleo advocates seem to be making is that you should eat food that the body is adapted to eating.

>> "The claim most paleo advocates seem to be making is that you should eat food that the body is adapted to eating."

In full, their claims fall closer to the following:

  P1. You should eat healthy foods.
  P2. Foods that the body is "adapted" to eating are healthy.
  P3. If paleolithic humans ate something, it means our bodies are "adapted" to it.
  C. We should eat what paleolithic humans ate.

The problems with the above line of reasoning are numerous. While most everyone would prefer to eat healthy when possible, the word "adapted" is ambiguous, and the argument that it's healthier to eat foods we're "adapted" to lacks evidence and is overly ambitious.

It's hard enough to examine healthiness on a food-by-food (or even an ingredient-by-ingredient) basis, so labeling broad categories of food as healthy or unhealthy is bound to be even harder.

Let's put that straw man logic more realistically:

  P1. If you want to have a good degree of health without requiring modern medicine, you should eat food that gives you a good degree of health without requiring modern medicine
  P2. Successfully reproducing in an environment without modern medicine requires food that supports or does not tarnish a good degree of health
  P3. Paleolithic humans successfully reproduced in an environment without modern medicine
  C. If you want to have a good degree of health without requiring modern medicine, eating what paleolithic humans ate will support or not tarnish that goal

Of course the problems with your reasoning are numerous. That's why intelligent people who eat the paleo diet don't make them. And they likely wouldn't propose the logic I did here. That's why they use studies comparing the health of hunter-gatherers to neolithic farmers. That's why they discuss scientific studies in support of meat/fat, and in opposition to grains. That's why they get angry at people who misappropriate their views.

Au contraire, plenty of intelligent people who follow the paleo diet make the flawed argument I just presented. I know a few myself.

In addition, I'd argue that the reasoning I presented falls much more closely in line with what's found on Wikipedia's "Paleo diet" article and top Paleo sites than does yours, which, strangely, seems to focus heavily on avoiding modern medicine. But this is irrelevant, since you yourself claim that "intelligent" followers of paleo likely wouldn't propose your logic, either.

So I must ask you: What reasoning would these people propose? "Using studies" is a supplement to proposing a logical framework that justifies a conclusion, not a replacement. Research isn't cited in a vacuum: it's cited to argue for or against some premise or conclusion. Also, the types of studies you refer to could just as easily be used to supplement the framework I provided as it could yours or any other. Thus, the fact that some paleo advocates would cite these studies isn't an argument for or against the accuracy of my characterization.

It seems a bit disingenuous to label one's reasoning a strawman without providing specific reasons as to why, or even providing the allegedly correct reasoning. If a group refuses/fails to articulate its position clearly and publicly, then who is truly to blame for those views being misappropriated?

>> P3. Paleolithic humans successfully reproduced in an environment without modern medicine

Many paleolithic humans did not successfully reproduce. Many died before being able to. Humans continued to exist because enough successfully reproduced.

Unless your personal health goal is that a sizable proportion of your cohort survive to reproduce successfully, this is not particularly helpful reasoning.

In any event, you are highly likely to make it to child-rearing age in economically developed countries. Our health problems occur later.

There's a great TEDx talk debunking the myths of paleo diets: https://www.youtube.com/watch?v=BMOjVYgYaG8

That video didn't debunk anything. It's just 22 minutes of straw man. It's never been about eating exactly what hunter-gatherers ate, and it has never followed any assumption that the hunter-gatherer diet is best possible diet.

It is based on evidence that hunter-gatherers showed excellent health, and those transitioning to a neolithic diet showed a health decline. Following that, it takes the sensible action and imitates the fundamentals of the diet, backed up by more cutting-edge studies starting to go against the "high-grain, low fat" spiel. It never claims to be "the best possible diet", nor the actual diet that hunter-gatherers ate. It doesn't need to be either to be a smart decision for your health.

Of course, I get the feeling that this is not really about whether or not the diet is valuable. People tend to take sides on the matter, and videos like these only worsen the problem. Most diets around are healthier than what you normally eat.

Your comment suffers from the affliction that "if it doesn't completely eradicate -foo-, then there's no point at all". If there was a magic food that cut your chance of getting any sort of cancer by a factor of 1000, your statement of 'you could still get heart attack/cancer in your 50s' would still be true.

The main article does this a little as well; there's something of a tone that says 'healthy food has all these other benefits, but since it doesn't stop cancer, it's probably not worth it'. It's weird, because I've never heard of anyone specifically choosing foods because of their reduction in cancer rates - people tend to choose foods that affect their current wellbeing, not future 'maybes'.

I'd go so far as to say that any claims of cereus types of foods being "healthier" are specious as well. As long as you're getting the required sustanence and not dying of anaphylaxis or whatever, you're good.

Everyone, even doctors, find a new food to demonize every few years, then flip and say it's the bet thing ever a decade later. Anyone remember when eggs were killing you? Or when the fad diet was low carbohydrate? Now eggs cure cancer and gluten is "literally Hitler."

Health nuts, as a rule, have no clue what they're talking about. They're just desperately looking for something to blame for their (or others') problems and using pseudoscience to justify it. (As for weight loss/gain, it's just simple thermodynamics. Caloric intake minus expenditure equals "duh.")

"Everyone, even doctors, find a new food to demonize every few years, then flip and say it's the bet thing ever a decade later."

Uh ya. New evidence comes to light, people change their minds. That's not necessarily a fault of the methodology.

This is true, so far as it goes. But obesity is unhealthy, and some food types are much more likely to make people obese than others. Specifically, "foods" (in quotes because often the worst offenders are drinks) with high caloric density and low satiability mean people take on huge amounts of calories without feeling full.

I think what caused such robust health among paleolithic humans is they didn't drive. They had to walk everywhere. Literally miles to find food.

I remember reading a study on paleolithic humans that said that even they had atherosclerosis.

What evidence is there that paleolithic humans had robust health?

I suspect there was a real (literal!) survivor bias is the healthiness of paleolithic humans while they were alive. In a hunter/gatherer society you had to remain healthy enough to be mobile. If you didn't you were probably left behind, and then you died pretty quickly.

Does the high levels of "fitness" of those alive mean they had "robust health" in general? I'd question that: I think cause and effect has been switched, and the only paleolithic humans left alive were those who remained in "robust health".

Bingo. Hunter gatherer societies are far less forgiving of the weak and sick.

This is all true, but the atricle says something quite different than what you are commenting on. The "original findings" which are being reversed were based on 4,000 pieces of peer-reviewed research.

After reviewing more than 4,000 studies, the [1997] authors were persuaded that green vegetables helped ward off lung and stomach cancer.

It's easy to dismiss a single instance as an arbitrary data point. When you can dismiss a large portfolio of such points--you have another problem. That problem is a core-weakness in methodology/approach/and institutional incentives. That seems to be the larger issue highlighted here.

Well, the sentence immediately preceding that one gets it right:

>The situation seemed very different in 1997, when the World Cancer Research Fund and the American Institute for Cancer Research published a report, thick as a phone book, concluding that diets loaded with fruits and vegetables might reduce the overall incidence of cancer by more than 20 percent.

With "might" being the most important word there. These 4,000 studies were all retrospective analyses, and retrospective analyses only find conclusions of the "might" sort, which is well understood by the scientists, but not so well communicated by journalists.

Still, a 20% "might" is a an absolutely enormous amount of potential upside in cancer prevention, even a "maybe" of this magnitude justifies great excitement. Which is why they embarked on the prospective study, which is the real story here.

It is absolutely ridiculous to conclude that there are methodology or misaligned institutional incentives based on this case, it's exactly how things should work. It's just another example of scientists being blamed by bad reporting that they have no control over.

That said, there are many other cases where methodology is wrong or institutional incentives are wrong.

You need to weight them by quality, from experience in my field of E&M the papers with 2k citations are correct and the ones with 4 citations aren't.

Also 4k papers is too much to go through by hand, so something else was done.

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