U.S. Dietary Guidelines: An Evidence-Free Zone

[Todd Allen]

Steven E. Nissen, MD, chairman of cardiovascular medicine at the Cleveland Clinic wrote the following opinion piece published in the Annals of Internal Medicine:

U.S. Dietary Guidelines: An Evidence-Free Zone

Quote

The lack of high-quality RCTs has left dietary advice to cult-like advocates, often with opposite recommendations. One group advises virtually complete elimination of carbohydrates from the diet, whereas others promote a virtually fat-free diet.

Very little of what we believe about nutrition is based on RCTs a better indicator of causal relationships than observational studies.  If you believe in the value of observational studies here's a recent one with results in stark contradiction to common widespread beliefs:

Food consumption and the actual statistics of cardiovascular diseases: an epidemiological comparison of 42 European countries

Quote

Results

We found exceptionally strong relationships between some of the examined factors, the highest being a correlation between raised cholesterol in men and the combined consumption of animal fat and animal protein (r=0.92, p<0.001). The most significant dietary correlate of low CVD risk was high total fat and animal protein consumption.

 

[TomBAvoider]

Funny coincidence, I was just scanning the BBC news website, and came across this:

 

http://www.bbc.com/future/story/20190116-a-high-carb-diet-may-explain-why-okinawans-live-so-long

 

"Solon-Biet has conducted a series of studies examining the influence of dietary composition (rather than sheer quantity) on ageing in animals, and her team has consistently found that a high-carb, low-protein diet extends the lifespan of various species, with her most recent study showing that it reduces some of the signs of ageing in the brain. Amazingly, they have found that the optimum ratio is 10 parts carb to one part protein – the same as the so-called Okinawan Ratio.

Although there aren’t yet any controlled clinical trials in humans, Solon-Biet cites epidemiological work across the world that all point to similar conclusions. “Other long-lived populations have also been shown to have dietary patterns that include relatively low amounts of protein,” she says. “These include the Kitavans, [who live on] a small island in Papua New Guinea, the South American Tsimane people and populations that consume the Mediterranean diet.”

So pick whatever it is that tickles your fancy - there are precious few things that have been *proven* in nutritional science.

[mikeccolella]

https://www.bluezones.com/2018/09/news-study-finds-low-carb-or-keto-diets-could-lead-to-shorter-lifespan/

We know from our research in Blue Zones longevity hotspots that the longest-lived people in the world eat a whole food, plant-slant diet that is highlighted with whole grains, beans, nuts, and leafy greens. Their diet is 90-95 percent plant-based and oftentimes about 50-65 percent of their daily caloric intake comes from carbohydrates. These are not highly processed carbohydrates like white bread or sugary drinks, but whole foods like sweet potatoes, beans, whole grains, and fruits and vegetables.

These massive global studies are another reminder that focusing on healthy and plant-based whole foods is a better long-term strategy than dieting

regarding Todd’s quote the cardiologist talks about virtually fat free diets. That’s virtually impossible on a WFPB diet because even kale and broccoli have fat. If you eat nothing but fruit and processed foods that have the fat removed you could do it. Something like non fat yogurt and fruit. Whole grains, legumes and vegetables have fats And when you eat them your not going to be virtually fat free. So not sure what the good doc was referring to??

according to cron o meter 16% of the calories in kale are from fat! 

[Genny]

You can actually eat so little fat that you can get to unhealthily low triglyceride levels.  That is not a myth or a lie.  I have done so--not intentionally.  I was even chubby then!  My total cholesterol was 105, and though my ratio was still "good," but I definitely felt incredibly tired after moderate exertion.  Doubling my "good" cholesterol took deliberately eating more fat, and it really improved my exercise capacity.

I'm definitely on the side of "plant slant" over veganism, which is literally impossible for the sustenance of human life without supplementation.  It seems pretty ludicrous to imagine that the healthiest eating pattern would be one that relies entirely on modern supplementation to keep you from dying.

[Gordo]

14 hours ago, Genny said:

literally impossible for the sustenance of human life without supplementation.  It seems pretty ludicrous to imagine that the healthiest eating pattern would be one that relies entirely on modern supplementation to keep you from dying.

1) Not impossible, just not very practical for most people.  Remember that animals don't make b12, bacteria do.  Some mushrooms, and fermented foods, and seaweeds contain b12.  Many water supplies (rivers and lakes) contain b12. b12 is in soil, so if you grow your own vegetables or get them from a trusted organic source, you could just eat them without "sand blasting" all the dirt off (again, not a very practical solution for anyone, we wash veges to remove pesticides and dangerous bacteria as well).  B12 supplementation is recommended for even meat eating, older adults.

2) Define "healthiest".  We know from cohort studies which diets are likely to lead to greatest healthspan and lifespan.  From a pure survival perspective, back in the day, it was most practical to kill an animal and eat it, then you could spend the rest of your time doing other important things instead of foraging for plants all day like the super muscular, vegetarian gorilla, and you don't have to store up a massive quantity of vegetables for the Winter in climates with a Winter.  But "nature" pretty much wants you to be healthy enough to survive and thrive while young, have kids, raise them long enough to succeed, then its done with you and best to kill you off quickly so you don't take resources away from the younger folks with better reproductive prospects.  This means pretty much anything you are going to do for maximum healthspan and/or longevity is probably going to be "abnormal" (like calorie restriction, cold exposure, or eating a plant based diet) and basically fighting against "human nature" to some degree. 

What diets do you know of that have been scientifically proven to reverse heart disease (the leading killer in the world)?  I only know of one, the plant based diet, and it seems the more extreme you do it, the better the results.  Buildup of fatty plaques can be observed with ultrasound evaluation of the carotid arteries.

What dietary factors fuel cancer if/when you get it?  High growth factors seem to contribute.  What diet results in high growth factors?  Do fully grown adults, past the age of reproduction, need high growth?  No.  Could this be detrimental to longevity?  Yes.

What diet has a proven track record of preventing cancer and boosting the immune system?   Not meat.  Literally thousands of plant-derived compounds are associated with a lower risk for most types of cancer when used throughout your lifetime.

 

[Genny]

You’re conflating a high protein/high meat diet with any diet that contains meat. 

If we put aside big game specialists, which were a successful niche for a number of reasons that had nothing to do with longevity, and look at societies of people who live a long time, they eat a main base of starches (grains, usually), beans, a variety of vegetables, (usually in that order) and limited but nutritionally important amounts of fruit and animals matter.  Some have substantial amounts of plant oil but most don’t.

None are vegans. No free living human society has ever been vegan. Some societies have had vegan practitioners, who become vegan as (usually older) adults as a sign of religious devotion. But never as a norm and never as a society. Some religious orders are vegetarian. No society is, again.

BTW, a good hunk of my family is SDA, and  Ellen G White’s ideas about food were kinda nutty. They were CERTAINLY not “whole foods”—food was almost penitential.  SDA has evolved to a more health-conscious-focus with the timing of the world wars and the roles of contentious objectors in medicine heavily as a result of that and also as a mission/humanitarian field.  But refined grain was totally a mainstay of White’s ideas of a purification diet.  Researchers really miss her emphasis on not overeating though and her absolute condemnation of any level of gluttony.  How does all that white bread and endless soy fit into the veggie-heavy PBWF ideal?  I’ll tell you.  It doesn’t.

A number of long lived societies actually do eat LARGE amounts of meat on specific feast days. But these are luxury, special occasion foods, not a daily sausage.

Also, India has crap all for longevity, ignoring healthcare related issues, even though a lot of the traditional diet should be super healthy. There is one big difference between the Indian diet and healthier Asian and Mediterranean diets, and that’s the high amount of butter in traditional Indian food. The rest really isn’t all that different, so why the high CVD, even controlling for smoking?

(I actually cook a lot of Indian food, but I swap out butter in almost everything for much smaller amounts of a vegetable oil of the appropriate smoke point.)

Chronic CR is a bad idea in humans, if CR is meant to push lean mass as well as fat mass down.

Time box feeding replicates real historical eating patterns.  So does prolonged fasting. Leanness without under-lean-massness has been quite achievable and has indeed been achieved by a reasonable number of people. Intelligent approaches will be looking to safely trigger the hormesis that our bodies actually rely on for optimum health rather than look for some cheat code that’s going to have some terrible downstream cost.