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Tuesday, March 13, 2012

Your Crackpot Diet May Be Killing You

A 28-year long study of 121,000 middle-aged men and women shows eating too much red meat significantly shortens your lifespan. On the other hand, things like whole grains contain "hundreds of thousands of protective substance."

Of course, what are massive scientific studies compared to a few testimonials, which, we all know, is the way real science gets done!

23 comments:

  1. Whatever. I like being 113lbs lighter.

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    1. Congratulations, August, losing that much weight is quite an accomplishment.

      Almost any diet that seriously restricts which foods you can eat might work, since the restriction tends to reduce caloric intake as well. You probably would have lost 113 lbs if you had eaten ONLY grains and legumes as well.

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  2. John D5:24 PM

    Note that if you set aside the book marketing, "Paleo" recommendations differ mostly in degree to today's consensus. The plans are full of vegetables, fish, and nuts. They do claim that eating plenty of red meat is fine, but, as with this study, suggest that people always choose less processed products for reasons of leanness and the absence of hormonal adulteration, etc. The real disagreement is about grains.

    Gary Taubes does offer a complete defense of endless saturated fat consumption in "Good Calories, Bad Calories", which shouldn't be dismissed out of hand. He could be wrong, but was thorough. He is more associated with Atkins than Paleo dieting. See his NYT article "Is Sugar Toxic?".

    Anyway, food-as-ideology seems really silly. It would be a shame for legitimate ideas to be attached to (and embarrassed by) crusaders.

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    1. John, I'm completely open to the idea that we generally eat too much starch and sugar. But something like the Harvard recommendations Karen DeCoster ridicules at LRC say exactly that: we should eat whole grains to the extent we eat grains, and that extent should probably drop for most of us. And refined sugar appears nowhere in their chart.

      Perhaps I have only seen the crankier of the paleo advocates!

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  3. I've also kept it off for those two plus years the statisticians appear to think significant.
    If I had kept eating grains I would have stayed fat. There is an addictive aspect to wheat- opiod peptides keep you craving more.

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    1. Again, August, well done. But there are lots of vegetarians who eat mostly grains and legumes, and I know of few fat vegetarians. (Of course, they exist!)

      Look, maybe "crackpot" is too strong a word: experimental and inadequately tested might be better. And the theory is shaky, too: paleo man clearly ate grains, and we show clear signs of adaptations for doing so, eg, the high amount of amylase in our saliva compared to chimps.

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  4. Eric Evans6:10 PM

    What are they implying in saying that the researchers took those other factors into account in their analysis? That the effects of those other factors were proven to be minimal in the face of red meat consumption? If so that would be a fairly shocking finding, and there would be no reason to relegate those facts to the tail end of the article. I'm not taking a position either way on a "primal" diet, I just think articles that present the potential error of a study in this manner have earned a good deal of skepticism.

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  5. I don't really have a stand on the whole primal thing, but epidemiological studies have a pretty bad track record.

    Coffee, fish oil, anti-oxidants, eggs, aspirin, statins, and now red meat. Good one month, bad the next.

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  6. Part 1

    Unfortunately I will not be able to address this in full due to certain limitations that you're aware of. However, I must say something and since my time is limited it will be somewhat lengthy. Strap in.

    I and my best friend from childhood (who has his Master degree in dietetics) actually read the science and journals relating to diet. In fact, I have been studying diet and exercise physiology for about 10 years (longer than my degreed friend) and my RD friend has stated many times that I put many of his peers (and his professors when he was still in school) to shame. I am not blowing smoke is all I'm trying to say.

    The preponderance of evidence leads to the conclusion that the human diet does not require as many carbohydrates as once thought, and that the amount of carbohydrate energy consumed in the typical American diet causes inflammation (the most prominent precursor to heart disease and other problems), as well as a variety of insulin response related ailments (insulin insensitivity, diabetes, obesity, etc). There is no debating this issue, so we can immediately take that as a given and get into the more detailed topics relating to the story that you linked to.

    First of all, I did not yet read the study for reasons that you are already aware of, however I have saved it and will do so later. Before I do I will make a few observations that I find to be pretty common with studies of this sort. If the persons in question are American (I will assume that they are due to the fact that Pan works at Harvard), then we can without a doubt assume that these people ate a grain-heavy and PUFA-heavy diet along with red meat and processed meats/foods. This is unfortunately a common fault with many dietetic studies, because the other foods that were eaten are not taken into account (i.e. the researchers are tunnel-visioned on one thing). I will assume that the researchers focused only on one food variable (red meat). Another problem with many of these studies is that they rely on the subjects to recall their diet over a period of time after the fact (i.e. how many times did you eat red meat this past month?). Like I said, this is based on past experience in reading such studies, this one certainly could be different (I'll know after I read it in its entirety).

    I should also mention that the last paragraph in this story admits, "...Pan and his colleagues found that the men and women in the study who ate the most red meat also tended to be heavier, less physically active, and more likely to smoke and drink alcohol than their peers." Sure, it does say that they took that into account, but it does not explain how they did so (how does one take something like that into account, anyway?). I also notice that there was no mention of grains or carbohydrate intake. That seems like a pretty big omission to me.

    Also, the story says that substituting other foods for red meat reduce the risk of dying in that stage of life by 7-19% (that doesn't sound too conclusive or substantial to me). I especially liked what the Swede said toward the end of the article, "Studies like Pan's are inherently iffy due to red meat's unhealthy reputation, which makes red-meat consumption difficult to tease apart from a person's overall lifestyle, Lindeberg says. "Red meat has been perceived as a villain for many years, and people who avoid red meat take all sorts of precautionary measures for their future health," he says. "It is not possible to statistically adjust for all of these measures." I agree, yet I read studies all the time that ignore this.

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  7. Part 2

    Now, let's get into the meat of things, shall we?

    We can probably safely assume that the study in question used conventional grain-fed beef. If this is the case then we can immediately conclude that the polyunsaturated fatty acid profile of that beef leaned heavily toward omega 6 fatty acids. If this is the case, it is no surprise that these people died early. In fact, I would not be at all surprised to find in their food logs (if they even exist in this study) that these people also consumed a great deal of hydrogenated vegetable oils and other sources of polyunsaturated fatty acids. After all, most American's omega fatty acid ratio of omega 6's to omega 3's is anywhere between 20:1 to 50:1 (I think that I read 30:1 is the average, but don't quote me on that)-- the ideal ratio is 1:1. What is the expected result of such out of whack omega fatty acid ratios? Chronic inflammation. Once again, there is no debate about this in dietetic circles. There is general agreement that the ideal ratio is 1:1, there is agreement that grain-fed beef (and processed/hydrogenated oils) are heavy on omega 6's, and there is agreement that the standard American diet produces a ratio very heavy on omega 6's. Is it any wonder that these people are dying early? Nope.

    Also mentioned in the article, additives may be a factor in early deaths. No s%$t, Sherlock!!! Then they say that red meat is harmful because if you char red meat it can produce carcinogens. Um, if you char any food it can produce carcinogens, red meat is not unique in that regard. So, these two tidbits can be ignored as completely idiotic.

    The thing that this article mentioned that had me rolling is the statement that cholesterol and saturated fat are bad for your heart. First of all, this idiocy started when Ancel Keys did his 7 Countries Study back in the 50s and it has perpetuated ever since. Keys' study actually focused on 21 countries, not 7, and when you view all of those countries on a graph you see absolutely no correlation. However, if you take out 14 of those countries, hey! you get a loose correlation. The fact is that there does not exist a single study that proves that saturated and/or dietary cholesterol have any effect on triglycerides or total cholesterol. In fact, carbohydrates (not fats) are the driver of triglycerides in the blood. Further, dietary cholesterol has no effect on how much total cholesterol is in your blood stream, because that is controlled by the liver. If you eat more dietary cholesterol, then your liver will simply produce less blood cholesterol, if you eat more dietary cholesterol, your liver will simply produce more blood cholesterol. Simple as that.

    Since I am talking about cholesterol I must admit that while diet will not change total cholesterol (other factor determine this), it will change the composition of the cholesterol, most notably the proportions of HDL to LDL (both type A and type B). For instance, it is true that saturated fat increases LDL cholesterol, but saturated fat only produces type A LDL (which is almost impossible to oxidize), not type B LDL (which oxidizes readily). Just in case you didn't know, it is type B LDL that is considered "bad", one of the reasons why is due to its ability to oxidize easily. In fact, this oxidation is very important in understanding all dietary fats, because fats that oxidize easily can introduce free radicals into the body, thus increasing inflammation and created a myriad of negative health effects. Interestingly it is the polyunsaturated fats that most easily degrade from heat and/or oxidize, while it is the saturated fats that are most stable (obviously, monounsaturated fall somewhere in between). Even more interesting is the fact that body fat is actually saturated fat-- why would the body store energy for future use in the form of a "bad" fat? That doesn't make any sense whatsoever.

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  8. Part 3

    You may think that I have jumped on the libertarian/primal/paleo bandwagon, when in fact I have been a primal/paleo eater since well before I was a libertarian or even knew what libertarianism was (I used to bodybuild). It seems that you are attacking primal/paleo eating primarily because libertarians are just now becoming aware of it, and you feel the need to criticize whatever it is that libertarians are doing. You have failed miserably, not because of what I have stated above (I was pointing out the failures of the article itself), but because of your assumption that somehow primal/paleo eating is a meat-based diet. While primal and paleo are very similar, they are not the same (I, Lew and Tom are actually primal eaters, not paleo eaters). The things that primal and paleo both have in common is that they are primarily vegetable based diets (if there was a primal/paleo food pyramid, veggies would constitute the base), with emphasis on consuming enough protein for cell synthesis and lean mass retention, lowering carbohydrates to only those levels needed by the body's functions (i.e. glycogen stores, cell synthesis, brain function; though the body can indeed fulfill these functions without any carbohydrates whatsoever through gluconeogenesis and the production of ketones by the liver), using fats as the primary energy/fuel, eliminating foods that cause chronic inflammation, eating whole foods, eating only animals that eat their natural diets (i.e. no corn fed beef, pork, foul and no farmed fish) and basing all of this on what macro and micro-nutrient profile would have been found before the advent of agriculture. I actually consume less meat on the primal eating plan than I ever have in any of my past eating plans.

    The fact is that you're attempting to claim that there is no science to back primal/paleo up, yet you haven't read ANY of the science to make such claims. There is a lot of science to back it up and more has been coming out, especially in the past few years. Sure, there is far more science making claims like the one above, yet many of them are just as flimsy as the one above. Since I don't feel like digging up a bunch of papers and my internet time is limited, I will instead refer you to Loren Cordain, Robb Wolf, Mark Sisson, Mary Enig, Uffe Ravnskov. They all have blogs, I suggest that you read them before you criticize a subject in which you have no understanding.

    I'll try to return to this post in the next day or so to see what your response is. See ya later Gene.

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    1. http://rationalwiki.org/wiki/Paleo_diet#Evaluation_of_claims

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  9. Argosy Jones1:17 AM

    Well, I think Fetz is probably right.

    However, in general, I think it's a fine thing to make fun of the Mises crowd.

    But I think lots of things.

    Thanks for fixing the comments so that I can use this thing again. My livejournal account wasn't letting me log in. Or else it was blogger's problem. Anyway, too much trouble to bother with.

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  10. Since amylase works on non-grain starches too, why would you think it's presence proves or disproves that we should be eating grains?

    People who are starving eat many things that are less than ideal out of desperation.

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  11. Nice troll, Gene! You caught a whopper. Or maybe your knowledge on the topic really does come down to a CNN report on a study and some Karen DeCoster blog posts. Yikes!

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    1. http://rationalwiki.org/wiki/Paleo_diet#Evaluation_of_claims

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    2. Well, that was something. You think Fetz will bite again?

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    3. I would certainly like to. There are a ton of errors, assumptions and false attributions regarding primal, as well as paleo, in that link. Also, it comes off as some sort of arrogant, know-it-all rant of douchebaggery. Unfortunately, since it does contain so much crap, my response would be about the same length as my last response. So, I will refrain from taking that much space in the comments section unless I get the ok from Gene. It's up to you Gene.

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    1. OK, Dave, on the very first fact I checked from Zoe's article, she is simply flat-out, dead wrong:

      "However, the researchers did take those [smoking, lack of exercise, etc.] and other factors into account in their analysis."

      And Zoe, is NOT a scientist, and has no peer-reviewed journal articles to her credit listed on her bio, just pop books.

      So, totally unreliable.

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  13. Replies
    1. And now an article from an English major.

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    2. And by the way, Dave, that fact that these people aren't nutrition scientists of course doesn't guarantee they are wrong and the scientists are right. It just makes the odds that is so extremely high. So I am betting with the actual professionals who publish in peer-reviewed journals, until I have a chance to spend 20 or 30 years studying this stuff like they have.

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