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Save The World; Eat Your Vegetables
I spent most of the day reading the newly-released Final Scientific Report of the Dietary Guidelines Advisory Committee (DGAC). This report will form the basis for the next 5-year revision of the U.S. Dietary Guidelines, due out later this year. The report is 571 pages long, and I won’t pretend to have read all of it, but I did read major portions. I did not do it for fun; it’s part of my job to know about this stuff.
I was particularly interested to see how the DGAC would handle the fact that, over the past five years, a critical mass of the public has become aware that public health experts have been, uh, “misrepresenting” the evidence for decades regarding dietary fat. There never was much, if any, real evidence that low-fat diets are good for you, or that saturated fat causes cardiac disease (despite the fact that both of these dogmas have been “settled science” since the 1970s.) But in recent years, several studies have been published that make it impossible to push low-fat diets any longer with a straight face, or low-saturated fat diets with much confidence. And much of the public is now aware of this new evidence.
So, I wondered, how would the DGAC handle this problem in a way that saves face?
The committee handled the low-fat diet part of the question simply — by ignoring it altogether. The only direct mention of low-fat diets I could find in their report was all the way back on page 453: “… dietary advice should put the emphasis on optimizing types of dietary fat and not reducing total fat.” Low-fat diets? Who said anything about low-fat diets?
The committee’s handling of the saturated fat question was far more interesting. They dutifully described four major meta-analyses published since 2009 that failed to show any association (let alone a causal effect) between saturated fat intake and cardiovascular disease. But they attribute this failure to the likely substitution of carbohydrates for saturated fats in the diets of the research subjects in these studies. (Despite decades of telling us otherwise, the committee now assumes we all know that refined carbs are deadly.)
But instead of concluding that maybe saturated fats aren’t so bad after all, the DGAC immediately elided to a different question. They cited a number of studies indicating that cardiac disease can be reduced by substituting polyunsaturated fatty acids (PUFAs) for saturated fats. Apparently, even if saturated fats aren’t really bad, PUFAs are even better. And to get all the PUFAs you need, the committee asserts (not quite correctly), you need to consume lots of vegetables, specifically vegetable oil.
There are several major potential problems with this formulation (which I won’t bore you with), and I suspect the DGAC is aware that their vegetable oil imperative might blow up on them (like trans fats) even before the next five-year update of their report is due. If that were to happen, it would be particularly tough to explain, seeing as how they’ve just had to abandon (without much comment) their beloved low-fat, high-carb dogma and are even now trying painfully to finesse their discredited saturated fat dogma.
What they need is some embarrassment insurance. And they found that insurance in the form of yet another branch of settled science: global warming.
You see, fellow Ricochet members, there is a much higher reason to abandon our animal fat diets than merely our personal health and well-being. By giving up saturated fats (and apparently, all those good omega-3 PUFAs we get from meat), we are not only saving ourselves from the ravages of cardiovascular disease, but we are also saving our planet. An entire chapter of the DGAC’s report is dedicated to this proposition. In the committee’s own words:
Moderate to strong evidence demonstrates that healthy dietary patterns that are higher in plant-based foods, such as vegetables, fruits, whole grains, legumes, nuts, and seeds, and lower in calories and animal-based foods are associated with more favorable environmental outcomes (lower greenhouse gas emissions and more favorable land, water, and energy use) than are current U.S. dietary patterns.
By eating the kind of diet the committee (and later this year, the US Government) is recommending (and regulating) for us, the DGAC asserts, the greenhouse gasses emitted by agricultural pursuits will be reduced by as much as 4%.
Even if it turns out that the omega-6 PUFAs we get from most vegetable oils are actually accelerating our atherosclerosis and cancers (as some studies suggest, especially if we cook with them), we would still be advancing our war on global warming by abandoning saturated fats. Since global warming is officially the greatest existing threat to mankind, this is a good trade and it will justify whatever minor mistakes in dogma the public health experts are still inadvertently (or otherwise) making.
Image Credit: wikicommons media, via Creative Commons License.
Published in General
I don’t envy your day.
We may have to watch our intake of vegetables from the cabbage family and the possible increase in methane emissions. After all, methane is a more potent greenhouse gas than CO2.
I have ignored all the government recommendations since 1960 when my daughter diagnosed with celiac disease. Grains out, carbs out, meat and butter in.
I can’t wait to see the new version of the food pyramid/my plate/whatever they call it next.
If we stop eating meat, domesticated food animals won’t be needed, so we can eliminate them and then they won’t fart, avoiding whatever that does to the ozone layer.
(Except in India where at least some of these animals are sacred [thank a Jain next time you meet one]).
That means that once we come out from under the vegetarian blanket, we’ll have to pirate food animals out of India, grow great herds of them, and once again enjoy the taste of beef.
A taste of beef. I can hardly wait for the vegetarian era to be over.
We usually cook with olive oil on high heat. (My wife can’t bare the time it takes on lower settings) I’ve been a little concerned about this. How bad is it for us?
What are some alternatives? Butter doesn’t seem to stick around in the pan long enough.
What? Mike, you haven’t read The Big Fat Surprise? Real oils are okay.
Mike,
I can’t tell you what to cook with, as I don’t yet have a Net Neutrality license for giving that kind of advice on line.
I’ll merely tell you what I do. I’m afraid to cook with most vegetable oils, because at high heat these oils readily oxidize (become rancid). The products of oxidation are readily absorbed through the gut, and appear to do some very bad things in terms of causing atherosclerosis and damaging DNA. (And so, our public health experts are in the midst of yet another massive experiment involving the American population to find out what will really happen when we eat this stuff. Check back in 20 years.)
Saturated fats, on the other hand, are quite stable at high heat and don’t oxidize. Butter is great to cook with, as is coconut oil (which contains mostly saturated fats). Olive oil (which contains monounsaturated fatty acids) is relatively stable for cooking, as long as you use relatively low heat. But I avoid cooking with corn oil, safflower oil, canola oil, etc., which are loaded with the easily oxidized omega-6 PUFAs now being pushed by our government in the name of climate change.
By the way, fast food fries, which used to be cooked with tallow back in the good old days, are now cooked in a vat of vegetable oils that remain under high heat for many hours, and constitute a veritable stew of toxic chemicals. This is likely one of the most dangerous foods Americans commonly consume today.
It already has blown up on them. They don’t spend enough time reading the research, I suppose, to understand that it has.
This bit of research was funded by the National Institutes of Health, btw, and performed, in part, by employees of the Federal Government. And published in 2013:
“Use of dietary linoleic acid for secondary prevention of coronary heart disease and death: evaluation of recovered data from the Sydney Diet Heart Study and updated meta-analysis”
Summed up in this interview:
So it turns out that in one of the key studies that was used to justify the consumption of vegetable oils they assumed that the fact that lower serum cholesterol caused by consumption of vegetable oils would lead to better health outcomes. They even recorded the actual health outcomes, but did not include them in the published study. So Hibbeln’s group went back and tallied up the actual health outcomes, and found out that they were much worse. Whoops.
Great post, btw.
P.S. And if anyone is wondering why the National Institute on Alcohol Abuse and Alcoholism is studying vegetable oils, it turns out that there’s a really good, but non-intuitive reason for it.
Olive oil is largely heat-stable. It’s the best vegetable-based alternative. Do make sure you’re getting actual olive oil, as it’s often cut with the cheaper, synthetic alternatives.
Use more butter then. Butter is the better alternative, especially if you get butter from pastured animals.
Tuck,
You are right that there are a lot of data out there strongly suggesting that omega-6 PUFAs, at least when not balanced by the addition of omega-3 PUFAs, may be as bad (if not worse) than trans-fats.
Vegetable oils in general are a recent invention, and the long-term effects of these newfangled designer oils is largely unknown.
My chief complaint about the public health experts who are complicit in forcing policy decisions on all Americans is not that they don’t yet have all the evidence, but that they are so supremely arrogant about it. Even when they are faced with the evidence that their prior dogmas have been killing all of us, they simply move on to the next version of their settled science, with equally sparse evidence to support it.
The difference in this latest report, and what prompted me to remark on it, was the subtle shift they made in the overriding purpose of their dietary recommendations. If shifting to a vegetable-based diet is saving the planet, whether or not doing so causes some folks to get cancer or heart disease becomes a relatively minor side issue.
We’ve always been at war with EastAsia.
You cannot fully balance the effects of over-consumption of omega-6 fats by over-consuming omega-3 fats. This is an attempt to add a fig leaf, but it does not work.
Yes, I’ve got the research. :) As you’re a doc, if you’re interested to see it, I’ll go dig it up.
Tuck,
If you can point me to studies on whether adding omega-3 reverses the damage caused by omega-6, I would appreciate it.
Of course, this point is moot to the experts. We can’t add too much omega-3 whether doing so works or not, because the chief source of omega-3 is animals.
Rule of thumb: If you’re trying to develop nutrition guidelines, and you find yourself using the word “sustainability” or the phrase “favorable environmental outcomes,” you’re not talking about nutrition anymore.
I believe it is every conservative’s duty to eat lots of protein and grow big and strong.
Dear Dr. Rich,
If I eliminate the cow, exactly what am I going to fertilize all of those fields of vegetables with?
Yeah, indeed.
In animals, indicating that adding long-chain n-3 is beneficial, reversing obesity:
“Animal obesity, which is characterized by elevated endocannabinoids (27), is classically induced by 60 en% fat diets containing 8 en% LA (2). Here, lowering LA to 1 en% decreased 2-AG + 1-AG, AEA, and reversed adiposity while maintaining a 60 en% fat diet. This indicates that the causal factor for inducing obesity in the 60 en% diet was the high LA composition of 8 en%, not the high calorie density. We also note that feed efficiency was much greater in the medium-fat diets compared to the high-fat diets. One explanation is that carbohydrates supplied 45 en% for the medium-fat diets but only 20 en% for the high-fat diets (28).”
On age-related macular degeneration (leading cause of blindness) suggesting that just adding n-3 is not enough, n-6 must also be reduced:
“CONCLUSION: Higher intake of specific types of fat–including vegetable, monounsaturated, and polyunsaturated fats and linoleic acid–rather than total fat intake may be associated with a greater risk for advanced AMD. Diets high in omega-3 fatty acids and fish were inversely associated with risk for AMD when intake of linoleic acid was low.”
You
mandatemake a guideline that everyone compost all the vegetable scraps. Were you being facetious, EJ?MLH – What do you think we do with all that cow manure? We grow vegetables in it.
It’s not that we would have a poop shortage if we eliminate the cow, we produce tons of it ourselves. But using human waste is more complicated. It’s slightly higher in metal content and has to be processed several times to kill human pathogens. The Forestry Service has used it for years to grow trees.
And me being facetious? Who would think such a thought?!?
Tuck,
Thanks for the references.
Tuck
Olive oil is largely heat-stable. It’s the best vegetable-based alternative. Do make sure you’re getting actual olive oil, as it’s often cut with the cheaper, synthetic alternatives.
Use more butter then. Butter is the better alternative, especially if you get butter from pastured animals.
How about bacon fat?
Oh. Yeah!
You’re welcome. This one’s a gem:
“The role for the ratio of n-6 to n-3 fatty acids in tumorigenesis has recently become the focus of omega-3 research. Emerging evidence suggests that the n-6/n-3 fatty acid ratio, rather than the absolute levels of the two classes of PUFAs, is the principal factor in the antitumor effects of n-3 PUFAs (10–12). Experimental data show that the efficacy of n-3 PUFAs in suppressing cancer growth depends not only on the amount of n-3 PUFAs but also on background levels of n-6 PUFAs (14). It has also been shown that the therapeutic benefit of dietary n-3 PUFAs is greatest when its proportion greatly exceeds that of n-6 PUFAs (15). According to recent findings (16, 17), the ratio of n-6 to n-3 fatty acids in today’s diet is ≈10–30:1, indicating that Western diets are deficient in n-3 PUFAs compared with the diet on which humans evolved and their genetic patterns were established (n-6/n-3 = 1:1). The excess n-6 PUFAs and the very high n-6/n-3 ratios may result in excessive and unbalanced production of n-6-derived eicosanoids. This may contribute to the increased incidence of modern diseases, including cancers (16, 17). Thus, balancing the tissue ratio of n-6 to n-3 fatty acids may be a feasible approach to the control of cancer. However, whether a high n-6/n-3 ratio (>15), as found in most Westerners, promotes tumorigenesis, or whether a balanced n-6/n-3 fatty acid ratio can reduce cancer development remains to be established in well qualified experimental in vivo models.”
Turns out, in animals, they can control the onset of sunburn and skin cancer via dietary linoleic acid ingestion. Like turning a dial. I used to be very susceptible to sunburn. Since fixing my diet, I neither need nor use sunscreen. It’s been on of my favorite side-effects.
Bacon fat is problematic. [P.S. See the subsequent comment for explanation of why.] Omnivores like chickens, pigs, and humans concentrate excess omega-6 fats in the body if they over-consume. The feed that factory-raised chickens and pigs eat is primarily grain, and therefore high in omega-6 fat.
So if you save your bacon grease (as I do) let it cool. If it solidifies, then it’s good. If it doesn’t, throw it out. Omega-6 fats are oils at room temperature.
You’ll find that if you get bacon from pastured pigs the grease is very firm. I’ve had bacon grease from supermarkets that never solidified.
And here’s my favorite. This is practically an evil-genius study, it’s so devious.
They fed soybean oil to salmon, and then fed the salmon to mice.
“…feeding mice [soy-fed salmon] containing lower PCB and DDT levels but high levels of linoleic acid (LA), exaggerated insulin resistance and increased accumulation of fat in the liver.
“CONCLUSION/SIGNIFICANCE: Replacement of [fish oil] with [vegetable oil]s in aqua feed for farmed salmon had markedly different spillover effects on metabolism in mice. Our results suggest that the content of LA in VOs may be a matter of concern that warrants further investigation.”
Fatty liver disease is at around ~30% prevalence in the US. It’s caused by eating LA. Yum.
Tuck,
Thanks again. I’m sure you see the problem here, which is to say, things are not as simple and clear-cut as they need to be.
As far back as the McGovern Committee in the late 1970s (whose report served as the precursor for the Dietary Guidelines for Americans), it was officially determined that publicly presenting certain details, or especially areas of uncertainty, in the dietary recommendations would be counterproductive to the goal of a healthy society. Several prominent researchers argued to the McGovern Committee that there was little firm evidence that saturated fats are bad, and that in any case it was known for sure that some fats are good. But the Committee brushed all that aside in favor of a message that would be simpler to convey. And we Americans were treated to the Fats are Bad, Carbs are Good message for the next 30+ years.
Based on the extensive literature search the DGAC conducted in producing this new report, I’m certain they’re well aware of the evidence that omega-6 PUFAs actually may not be the dietary panacea they would like them to be. But, my dear Tuck, problems like the ones you’re so nicely documenting (e.g., the importance of omega-6 vs. omega 3 PUFAs), are just too complicated for us regular folks to understand in the way we’re supposed to understand them.
If the DGAC decided to go into the weeds, and attempted to convey to the public (or worse, to their government overseers) that maybe people need to be careful about omega-6/omega-3 ratios, or that when we’re cooking with vegetable oil we’re eating lots of new oxidized chemicals that haven’t even been fully characterized (let alone proven safe), something very bad would happen to them. (“Bad” likely having to do with loss of grants or other perks, rather than “bad” in an ISIS kind of a way. We haven’t sunk quite that far. Yet.)
I wish I shared your confidence.
Correct me if I’m wrong, but isn’t it true that dietary guildelines used to be published by the Department of Agriculture, but that they are now joint project of Agriculture and Health and Human Services?
Unless I’ve been misinformed, it provides a perfect (hipposcat) excuse for the DGAC.
“Dietary guidelines used to be produced by a department whose mandate is to promote agriculture rather than a department whose mandate is to promote public health.”
Thanks for the update, Dr. Rich. Appreciate it.
A few words of definitely not advice! for people looking around for various cooking oils: Both olive oil and butter smoke, unpleasantly, at high heat. Great minestrone cooks long ago took to starting off with olive oil and butter together, at moderate heat, for the first ingredient, the onions.
When you prepare fowl by any method, you can save the juices and chill them. What solidifies on top is culinary gold, especially in biscuit and bread-baking.
Lard is for pies; tallow is for candles, or better yet, the wood boiler. There: freely-exchanged opinions, as refreshment after reading about government guidelines.
Phooh. You’ve not lived until you’ve eaten tallow-fried French fries. McDonald’s built its empire on that recipe. It’s an important ingredient in Twinkies. We also use it for deep-frying our Christmas empanadas, a Colombian tradition.
And it makes a fine candle, that is true.