You may have heard the expression “Knowledge is power.” Well – today – we’re going to give you more power to control your diet and lifestyle – by giving you the facts. Welcome to the NutritionFacts Podcast. I’m your host – Dr. Michael Greger.
Today, we conclude our series on how industries impact dietary and health guidelines. Did you know that the meat industry’s own study concluded that meat consumption increased the risk of cancer, heart disease, diabetes, and premature death? Here’s the story.
A series of papers published in the Annals of Internal Medicine that largely discounted all but the highest quality randomized studies reached a conclusion directly contrary to the public health advice we’ve heard for years. They suggested that we should continue our current consumption of both red and processed meat. The authors based their exclusion of evidence on the so-called GRADE (Grading of Recommendations Assessment, Development, and Evaluation) criteria, which were mainly developed for evaluating evidence from drug trials. We need randomized double-blind, placebo-controlled trials for drugs, but strictness of these criteria would probably cause evidence for just about every dietary, lifestyle, and environmental factor related to chronic disease to be graded as “low” or “very low.” If the GRADE criteria were used to evaluate the evidence for other factors related to diet (such as inadequate fruits and vegetables, or too much soda or alcohol), whether or not exercise is good, safe sex, sleep, smoking, or air pollution, “none of the current recommendations on these issues would be supported by high- or even moderate-quality evidence” using the drug trial criteria.
But even after ignoring major parts of the available evidence, they still found an association between meat intake and an increased risk of cancer. And not just cancer. They found that adherence to dietary patterns lower in red or processed meat intake may result in decreased risk for premature death, cardiometabolic disease, and mortality (meaning the risk of getting and dying of diseases like heart disease and type 2 diabetes), as well as the risk of getting cancer and dying from cancer. Yet, they still concluded, in their dietary guideline recommendations: “continue your current red meat consumption,” “continue your processed meat consumption.” Forget the whole premature death thing, cancer, heart disease, diabetes—just keep eating your burgers and bacon.
So, you have these dietary guidelines developed by some self-appointed panel that are tantamount to promoting meat consumption––despite their own findings that high consumption is harmful to health. How did they square that, contradicting the evidence generated from their own meta-analyses? There’s only one body of evidence. They found the same risk that all the other reviews found. “So, they’re not saying meat is less risky; they’re just saying the risk is acceptable.”
Well, you do have to consider the risk and benefits. We covered the harms. “[Their] own data show that a moderate reduction in red and processed meat consumption can reduce total mortality by 13 percent, heart disease mortality by 14 percent, cancer mortality by 11 percent, and type 2 diabetes risk by 24 percent.” What are the benefits? “In short, omnivores enjoy eating meat.” Uh, okay. “[G]iven peoples’ attachment to their meat-based diet, the associated risk reduction [in our leading killers like cancer, heart disease, and diabetes] is not likely to provide sufficient motivation to reduce consumption of red meat or processed meat.”
So, therefore, eat up! In fact, they even say straight out that unlike the other dietary guidelines suggesting we limit consumption of stuff because of like the cancer thing, these other guidelines have paid little or no attention to the reasons people eat meat, whereas they did a systematic review of preferences regarding meat consumption, and people who eat meat enjoy eating meat. Maybe that’s even why they do it.
They’re generally unwilling to change their meat consumption, even in response to health concerns; so, the panel believed (the panel, you’ll remember, with generous support of a group getting millions every year from the meat industry)…the panel believed that for the majority of individuals, the desirable effects, like lowering your risk of family-devastating cancer and heart attacks associated with reducing meat consumption, probably do not outweigh the undesirable effects, like having to give up all that yummy meat. This is what led them to make their recommendation to “continue current consumption.”
That sounds like something straight out of the journal Meat Science. Why should we keep eating red meat? Because of the enjoyment. “People [also] like to smoke.” “They like to drink soda, they like to have unsafe sex.” “It’s kind of like saying: We know [motorcycle] helmets can save lives, but some people still prefer the feeling of the wind in their hair.” So, let’s just tell people to not wear helmets? But you’ll actually see this argument. “Complying with dietary recommendations imposes a ‘taste cost’ on consumers,” so how about “socially desirable dietary recommendations that are most compatible with consumer preferences” (you know, that best balance of health benefits against “taste cost”)?
So, hey, even if science told us that eating butter is unhealthy, its taste justifies the continuation of using it.
What do you expect from NutriRECS, the meat-industry-partnered panel that also published the paper criticizing the sugar guidelines, funded by the soda and candy industries?
They aim to produce nutritional guideline recommendations based on the preferences of patients. So, what’s next? Just telling people to eat doughnuts and ice cream all day? Yet the Annals published the meat papers with a press release saying, “No need to reduce red or processed meat consumption for good health.” Using the same methodology and rationale, they might as well have said: “No need to quit smoking for good health” or “No need to exercise for good health.” As Dr. Katz, director of Yale’s Prevention Research Center, put it: “Guidelines opposing the very data on which they purport to be based are not science; they are anti-science.”
In our next story – Big Meat downplays the magnitude of meat mortality.
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 some new agent, to which hundreds of millions of adults had not already been 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.”
Don’t want to die prematurely? The final story in our series – might help you avoid – doing just that.
According to the Global Burden of Disease Study, diets high in processed meat, like bacon, ham, hot dogs, lunch meat, and sausage, may kill off more than 100,000 people every year––mostly due to heart disease, but also cancer and diabetes, resulting in millions of healthy years of life lost every year around the world. And it doesn’t take much. The Union of Concerned Scientists estimated that if Americans could cut down to an ounce a week, thousands of annual cancer deaths could be averted. But that’s on a population scale. How can we better understand our individual risk?
Though the NutriRECS panel in the Annals of Internal Medicine meat papers I’ve done the last few videos about discarded their own findings, using their numbers, a reduction in red and processed meat consumption is associated with a 13 percent lower risk of premature death. What exactly does that mean? What does a 13 percent increased risk of death mean? To get a better handle on it, let me introduce the concept of microlives.
Acute risks, such as riding a motorbike or going skydiving, may result in an accident. A good way to compare such risks is with a unit known as a micromort, defined as a one-in-a-million chance of sudden death. I did a really fascinating video about it recently. “However many risks we take don’t kill you straight away: think of all the lifestyle frailties we get warned about, such as smoking, drinking, eating badly, not exercising, and so on. The microlife aims to make all these chronic risks comparable by showing how much life we lose on average when we’re exposed to them.” A microlife is defined as 30 minutes of your life expectancy.
Why is that? Well, someone in their 20s, a 22-year old man or a 26-year old woman, may have, on average, about 57 years left. That’s about 20,000 days, or 500,000 hours, or 1 million half hours. Aha! So, that is how they define a microlife, a reduction of one of the million half hours we may have left. Here are some things that would, on average, cost a 30-year-old man one microlife. Smoking two cigarettes, drinking two pints of beer, or every day they live 11 pounds overweight. See how helpful this can be in terms of comparing risks. So, drinking a pint of strong beer cuts your life expectancy short as much as smoking one cigarette. If it’s unthinkable to you to have so little respect for your own health that you’d light up twice a day, maybe one cigarette in the morning and one at night, then it should be just as unthinkable being 11 pounds overweight.
Alternatively, you can compare life-extending behaviors. For example, eating at least five servings of fruits and veggies a day may add an average of four years onto your lifespan for men, and three years for women. That’s up to twice as beneficial as exercising every day. Exercise for 20 minutes, and you add an hour to your life––two microlives. So, for all those who say they don’t have time to exercise, it’s like a three-to-one return on investment. Give 20 minutes of your life to get 60 minutes of life. Beyond that, there’s a bit of diminishing returns, but exercise an hour a day, and get back more time than you put in.
Okay, so what about the meat? Each burger is associated with the loss of a microlife.
So, it’s as if each burger were taking 30 minutes off your life. So, lifespan-wise, one burger appears to equal two cigarettes. If it wouldn’t occur to you to light up at lunch, maybe you should choose the bean burrito instead.
And processed meat is even worse. There are a couple of equivalent ways you could say it. Imagine two people who are identical in every way, except that one eats around 50 grams of processed meat a day, which is like one large sausage or hot dog, or a few strips of bacon, and the other eats none. Eating that single serving of processed meat every day is expected to take around two years off the length of your life. Two years less with your loved ones, your grandkids, your spouse, two more years of mourning. Or you could think about it on a day-to-day basis. Eating a baloney or ham sandwich every day, just two slices of deli meat, is expected to take around one hour off your life each day. If you don’t think there are ever enough hours in the day, you may have effectively one less, depending on what you pack for lunch. Alternatively, you could think about it in terms of “effective age.” Eating 50 grams of processed meat a day is expected to add around two years onto your “effective age,” meaning basically give you the annual chance of dying of someone two years older.
In summary, wrote the chair of Nutrition at Harvard and colleagues, the NutriRECS meat recommendations suffer from important methodological limitations and involve misinterpretations of nutritional evidence. “To improve human and planetary health [as a side bonus], dietary guidelines should continue to emphasize dietary patterns low in red and processed meats and high in minimally processed plant foods such as fruits and vegetables, whole grains, nuts, and legumes [beans, split peas, chickpeas, and lentils].”
Let me end with a quote from Dr. Dean Ornish about the Annals meat papers that suggested people should continue to eat meat with abandon. His Lifestyle Heart Trial was one of the many studies the meat panel ignored. It showed that a plant-based diet and lifestyle program could reverse the progression of even severe coronary heart disease, the #1 killer of men and women. The control group actually made modest reductions in meat comparable to those in the Annals review and showed continued worsening of their atherosclerosis. “I take solace,” Ornish said, “in knowing that the light drives out the darkness. But, these days, the light has to be very bright indeed. Caveat emptor. Don’t be fooled. Your life may depend on it.”
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