Below is an approximation of this video’s audio content. To see any graphs, charts, graphics, images, and quotes to which Dr. Greger may be referring, watch the above video.
Across the board, a series of studies published in the Annals of Internal Medicine found a statistically significant association between lower consumption of red and processed meats and lower total mortality (meaning living a longer life), lower cardiovascular disease mortality, as well as lower risk of dying from cancer. Yet remarkably, the authors of these studies concluded that people should ignore all the other dietary guidelines and keep eating meat to their heart’s content––or rather discontent.
They offered three reasons why their panel reached a conclusion at odds with other contemporary dietary guidelines that advise people to cut down on meat. One reason is taste. In short, people who enjoy eating meat, enjoy eating meat. I did a whole video on this, but in short, taste preference probably shouldn’t be a major factor in developing dietary guidelines. Many people don’t want to quit smoking, stop drinking, or exercise more, but that doesn’t change the science; it shouldn’t change the public health recommendations.
A second reason they explain why their recommendations differ from everyone else’s is that other guidelines didn’t use the so-called GRADE (Grading of Recommendations, Assessment, Development, and Evaluation) approach. And no wonder, since GRADE was mainly developed for evaluating evidence from drug trials. There are grading systems for diet and lifestyle approaches, but the meat panel chose to inappropriately apply GRADE, which could similarly be misused to undermine recommendations about tobacco, air pollution, trans fats, you name it. I have three videos delving deep into all that, but this video is about the third reason they give for ignoring meat reduction advice. Other guidelines didn’t highlight the “very small magnitude” of the meat effects. In other words, even if meat does cause heart disease, cancer, diabetes, and death, it doesn’t cause that many heart attacks, doesn’t kill that many people, doesn’t cause that much cancer to offset all the juicy taste benefits.
Of course, it matters what people replace the meat with. Replacing even 3 percent of calories from animal protein with plant protein is linked to living longer, but eggs were the worst. Yes, replacing red meat protein with plant protein sources may lower overall mortality more than 10 percent, but getting rid of egg protein, and we’re talking more than 20 percent lower risk of premature death. So, if someone reduces meat consumption by swapping a burger for an egg salad sandwich, that particular reduction in meat could mean more mortality.
But maybe they concluded there was such a small effect only because “major bodies of evidence were omitted, [and] relevant studies excluded because the authors didn’t like the results.” It’s not that there aren’t tons of randomized controlled trials about meat; it’s just that they appeared to cherry pick a few to fit their agenda, discarded studies that even met their own criteria, and wrongly rejected randomized controlled trials clearly showing that meat increased risk factors like cholesterol or blood pressure. Why wasn’t PREDIMED included, or the literally hundreds of randomized trials on the DASH diet?
What about the Lyon Diet Heart Study, which involved randomizing individuals to a more Mediterranean diet, with significant drop in meat consumption? Compared to the control group, they experienced a 70 percent reduction in mortality from all causes put together. Why did they exclude that study? They excluded it because, in their words, it reported an “implausibly large treatment effect.” In other words, it worked too well.
No surprise, given that this so-called NutriRECS meat panel was partnered with, and had multiple people on the payroll of, Texas A&M Agrilife, which receives literally millions of dollars of meat industry money every year. So, you probably won’t be shocked to find out they also excluded research comparing health outcomes of vegetarians to meat eaters. As they described it, they were interested in realistic decreases in meat consumption, like cutting down three servings per week. In fact, the study that they mostly relied on, the Women’s Health Initiative, achieved only a difference of 1.4 servings of meat per week. That could be like a half an ounce difference in meat consumption per day—about a fifth of a hamburger.
“Participants in the Women’s Health Initiative reduced meat intake only modestly, resulting in a modest reduction in mortality related to breast cancer. This finding in no way supports the notion that there is ‘No need to reduce red or processed meat consumption for good health.’ Rather, it shows that modest dietary changes yield modest benefits.” “As an analogy, if studies showed that modest reductions in tobacco use yielded only modest health benefits, it would be inaccurate and dangerous to suggest that there is ‘No need to reduce tobacco use for good health.’” “To say that small increases in meat consumption only cause small increases in the risk of disease doesn’t mean that eating meat is good for you. That’s like saying that smoking 24 cigarettes a day increases your risk of lung cancer only a little more than smoking 20 cigarettes a day [being careful not to include any studies that compared smoking 24 to smoking none], and then erroneously concluding that smoking isn’t that bad for your health.”
Despite all that, despite ignoring evidence, excluding evidence, the meat panel “nonetheless found entirely consistent, clinically meaningful, statistically significant adverse effects of eating more meat and processed meat on all-cause mortality, on cardiovascular disease, on cancer, and on diabetes. That they did so despite the obstacles they put on the path to this finding is nearly incredible, and directly bespeaks the magnitude of adverse effects of meat and processed meat intake on health.”
Based on their meta-analyses of large cohorts, dietary patterns with, again, just a moderate reduction in red and processed meat consumption were associated with lower total mortality by 13 percent, lower cardiovascular disease mortality by 14 percent, lower cancer mortality by 11 percent, and a 24 percent reduced risk of type 2 diabetes. We spend tens of billions of dollars a year trying to tweak risk factors by about this magnitude. And this one intervention—a reduction in meat consumption—appears to do all those things at the same time. There are statin drugs that can reduce heart disease risk, but actually increase risk for type 2 diabetes and have little effect on cancer. If there was a drug that did as much for your health, it would be a multi-billion-dollar blockbuster.
The chair of Nutrition at Harvard estimates a moderate reduction in red meat consumption could prevent 200,000 deaths per year. Now, the meat panel can call that a very small effect if they want to, but I imagine it’s no small effect to those 200,000 families.
The numbers they found are on par with the amount of cancer and heart disease attributable to second-hand smoke and based on the same kind of studies—population studies. It’s not like they randomized people to sit in smoky rooms all day for a couple years. But no rational person who looks at the public health data around the effectiveness of smoke-free zones would argue that people should continue exposing themselves to secondhand smoke. So why do the same for red meat and processed meat?
The smoking analogy is actually a good one. “[I]magine researchers select studies with extremely small between-group differences in the number of cigarettes smoked per week. They avoid any studies that actually compare smoking to non-smoking [i.e., meat-eating to vegetarian]. They find that despite the small differences in exposure, there is still a clear and consistent benefit to smoking less. They then apply methods of grading the evidence that strongly favor randomized trials over all other methods. Since there are few if any randomized trials of smoking, they conclude that they have very low confidence in the reliability of their own findings. On that basis, they publish guidelines recommending—that the public simply continue to smoke. After all, they reason, people who smoke like smoking.” That really does sum up the Annals papers in a nutshell.
That reminds me of a quote from a famous paper published in 1958, compiling all the most poignant evidence linking smoking and lung cancer, after coming up against those same charges of inadequate proof. This quote could just as well have been written about the state of science on meat today. If the mountain of evidence they found “had been made on a new agent, to which hundreds of millions of adults were not already addicted, and on one which did not support a large industry, skilled in the arts of mass persuasion, the evidence for the hazardous nature of the agent would be generally regarded as beyond dispute.”
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