What Happens When People Stop Eating Animals
Dr. Campbell’s colleagues’ findings are remarkable – but do they prove anything about the Whole Food Plant Based Diet? Plus: Summary of our findings about Dr. Campbell’s scientific research.
Welcome to Part 5 (of 7) of our special series about holistic nutrition and some of the research behind the Whole Food Plant Based Diet.
To learn more about the series, check out the Introduction here, where I explain how this project is something very different than yet another polemic for or against veganism.
These posts are much longer and far more complex than what I usually post at The Healthy Jew. You might find them boring – or the most interesting thing you’ve read in months. (To keep things simpler, I’ve taken out the sources from the online post - you can find them in the PDF at the end.)
If this isn’t your cup of tea, we’ll be back soon with concise, practical guides for Jewish wellness and the Land of Israel.
In the meantime, here’s a really cool picture I took last week:
This is Shlomo from our Healthy Jew class at Lev Hatorah. He’s standing on Mount Shlomo to the north of Eilat, holding my book, Land of Health: Israel’s War for Wellness, in the exact same spot that its cover picture was taken last year. That’s coming around full circle, don’t you think?
Now let’s get to business…
The final stage of Dr. Campbell’s development of the WFPB diet is when he sought and found the conclusions of other researchers and clinicians which showed that indeed the diet prevents and even reverses many diseases. Part II of The China Study is devoted entirely to surveying how diet affects the full spectrum of diseases affecting modern society.
In Dr. Campbell’s view, as he described in his response to critics, this stage is the most central to his case for the WFPB diet:
Perhaps the most important evidence of all [is] the clinical experiences of the practicing physicians who I had come to know… For me, these medical practitioners, entirely on their own initiative and knowledge, were advising, with impressive success, their patients with the same information that I had come to know from the scientific literature and laboratory. The proof is in the pudding, so to speak. The idea works!
Before we take a look at the details, I’ll note that The China Study’s critics are much quieter regarding this section of the book. They didn’t bother fact-checking many book’s sources, or even getting too involved into the details. Is it because the clinical evidence supports the WFPB diet where laboratory experiments and the China Study could not?
Not at all. As they point out briefly, pretty much everything in this section is deeply confounded by other variables. It’s not necessary to pore over scientific journals to challenge Dr. Campbell’s conclusions. A careful reading of the The China Study sufficed to leave its critics astonished at how such a prestigious scientist stretched such tenuous evidence so far.
What would Dr. Campbell respond? I can’t know for sure, but he does emphasize repeatedly how the weight of his claim lies in the breadth of the evidence, not in any individual study, even admitting that you can find a single study to support any idea in the world. So he’d probably dismiss claims of confounding as too reductionist, missing the beauty of the “whole” forest because a few of its trees are deformed. Of course, this won’t calm his critics: if each block of the structure can’t at least stand on its own, we’re left with nothing more than a house of cards.
What follows is an overview of the clinical research in favor of the WFPB diet and its myriad shortcomings. Some of the specific problems we already met regarding the China Study; others will be new.
Heart Disease in America
Heart disease is the top killer of Americans, with skyrocketing rates for close to a century. Starting from the years after World War II, the Framingham Heart Study, named after the participants’ town outside of Boston, followed thousands of Americans over the course of their lifetimes to try identifying the causes of heart disease. By 1961, this landmark study had revealed risk factors for heart disease such as blood cholesterol, blood pressure, exercise, smoking, and obesity.
Particularly important is that it ended the question about blood cholesterol, showing decisively that it raises the chance for heart disease. Discovering these risk factors was a paradigm shift in how to look at heart disease: it’s not a natural part of the body’s “wearing down,” but a preventable process with specific causes. As the researchers wrote, “It appears that a preventive program is clearly necessary.” This research spurred vast drug industries dedicated to lowering risk factors; for example, Americans spend $30 billion a year to control cholesterol and high blood pressure.
Where are we today with heart disease? The debate rages on about the relationship between disease and diet, and on whether dietary cholesterol and animal foods are primary causes of elevated blood cholesterol and heart disease. In the meanwhile, treatment still focuses on extending the lives of people with advanced diseases instead of preventing or reversing its course. New chemicals and technologies, advances in hospital care, and lower smoking rates have indeed lowered mortality, but heart disease remains our leading cause of death. In fact, the disease’s occurrence is the same as fifty years ago, and the age of onset is getting lower. So we remain as sick as ever, but are getting better at pushing death around the corner.
Besides the human cost in lives and suffering, the material expense of our battle with diseased hearts is astronomical, with bypass surgery running into hundreds of thousands of dollars. The benefits of this invasive procedure don’t even last; within a decade half of patients will have either died, had a heart attack, or their angina will return. Other surgical interventions also yield similarly temporary results. Cholesterol lowering drugs cost Americans $35 billion in 2010. Projections have it that by 2030 the American heart disease establishment alone will cost more than the economies of most countries. All this isn’t surprising considering that they do nothing to cure the actual disease.
The truth, concludes Dr. Campbell, is that animal protein is the true culprit behind the risk factors identified by Framingham, particularly blood cholesterol. But how does he know this? Note that Framingham never identified dietary cholesterol, a nutrient contained only in animal foods, as a cause of heart disease. The risk factor was only blood cholesterol, that is the lipid as it’s mostly produced inside the human body by the liver. Perhaps eating more cholesterol means that more cholesterol ends up in the blood. But maybe not. In fact, in a finding that one of the study’s directors called “disappointing,” decades of following Framingham participants failed to show any positive link between dietary cholesterol (found only in animals) or saturated fat (mostly in animals) and blood cholesterol.
Yet this little problem didn’t stop Dr. Campbell from blaming animal foods for causing heart disease. He fills the missing gap by showing us mid-twentieth-century epidemiological and clinical studies which showed that saturated fat and dietary cholesterol indeed predict heart disease mortality.
But with a closer look, there isn’t much convincing evidence. All the observational studies involved comparing large populations of people, a methodology riddled with confounders. Who says that the reason that Papua New Highlanders have less heart disease than average Americans is because they eat less animal foods and not because they exercise more or have less stressful lifestyles or eat less processed foods? And the clinical studies all involved patients who were already sick, so they won’t prove much about prevention for the general public. There is also no mention of the quality of these early studies.
Dr. Esselstyn and Dr. Ornish
Yet there might be more recent evidence connecting animal foods with heart disease.
The China Study reports that two doctors have seen spectacular results in treating heart disease with diet, saving hundreds of patients by counseling them to live a healthy lifestyle, which includes eating a WFPB diet.
Dr. Caldwell B. Esselstyn conducted a study of the WFPB diet with twenty-three heart patients, and the eighteen who stuck with it had no coronary events (except for one who strayed from the diet and had chest pain until he returned to it). Eleven of them agreed to be tested and were found to have reduced blockages to their arteries.
Dr. Dean Ornish did a test which had participants eating barely any animal foods, eating many whole plant foods, exercising, and practicing stress management exercises such as meditation and breathing. His trial also showed regression in the disease for a vast majority of his patients. Of course, all these programs cost a fraction of surgery.
Summing up the evidence, Dr. Campbell stands appalled that the national heart organizations who are supposed to guide us toward health instead continue to offer half-hearted proposals to moderately reduce saturated fat intake, leaving accepted blood cholesterol levels very high. In his words: “the fact is that a blood cholesterol level of 200 mg/dL is not optimal, a 30% fat diet is not “low-fat,” and eating foods containing any cholesterol above 0 mg is unhealthy.”
The work of these doctors, and some others like them, is indeed groundbreaking. They have shown that lifestyle changes have a profound impact on advanced heart disease. But does their experience justify putting the whole world on a WFPB diet forever?
Even a cursory glance at the details of these studies shows a more complicated picture. As Dr. Campbell himself describes, the Ornish study is deeply confounded by a whole host of additional changes that his patients made. There is no evidence that drastically reducing animal food intake was the cause of positive health outcomes more than one or more of the other parts of his program.
Dr. Esselstyn did focus his study around the WFPB diet, and claimed together with Dr. Campbell that the benefits of his diet result at least partly from the absence of animal foods.
But Denise Minger has many problems with this claim. First of all, Dr. Esselstyn’s book on his research shows that his plan also eliminates all oils, which includes harmful ones such as unbalanced omega-6 and polyunsaturated fats. There is also no junk food, or even processed foods. In other words, he promotes the “whole food” part of the diet no less vigorously than its “plant based” component. Which makes us wonder if perhaps all the benefits resulted frome eating whole foods.
The study also suffers from severe design flaws. The original study was with twenty-two patients, of which only eighteen even finished, and even from those eighteen apparently only eleven came back for data collection. So a full half either didn’t finish or weren’t measured, which is disturbing: when lots of people drop out of a study, usually the ones who stay are the successful ones, which can misrepresent the findings to be more positive than they really are. Other problems are the lack of a control group, which means the results might have been just chance, and the lack of any randomization which means that they were all volunteers – that is people who anyways have a propensity for the changes in the plan, and might well have other healthy habits such as exercise.
The Red Pen Reviewers similarly challenged The China Study’s conclusions from these experiments. Like Minger, they agree that Dr. Ornish’s experiments were designed well, but didn’t isolate any specific aspects of his program, so we can’t know if it’s some or all of the changes that make the difference. And Dr. Esselstyn’s study was questionable in its methodology and analyses.
(Yet the Red Pen reviewers still grade the book’s claim that the WFPB diet protects and reverses heart disease as having “moderate evidence” (3 out of 4) based on lots of other research showing heart benefits in whole plant foods in several ways. But apparently they refer to current heart patients, not the general population.)
Norway in World War II
The evidence provided by the doctors doesn’t end with what’s brought in The China Study book. In the documentary Forks Over Knives (which features many of the book’s main claims and players), Dr. Esselstyn mentions more proof for the connection between heart disease and animal foods. When the Germans occupied Norway in 1939, disease rates plunged when the invaders confiscated all livestock for their troops, only to bounce right back after the war. There is even a nice graph showing this. This all implies that the cause of less heart disease in Norway during WWII was because they ate less meat.
But looking carefully at the raw data, Denise Minger demolishes the argument. Not only were meat and milk reduced, but also sugar and margarine intake went way down. And they ate lots more vegetables. And they ate three times more fish. Moreover, the year that showed the greatest mortality drop (1941) was the year before animal products were rationed – but the one after breads, sugars, and others foodstuffs were rationed.
Another interesting point is that the government encouraged citizens to forage in the forests for all sorts of edible flowers, berries, and other plants, suggesting which species are healthiest and where to find them. These wild fruits and vegetables are loaded with healthful antioxidants, much more than farmed variations.
A third problem is that the data on heart disease might have been confounded by the rampant infectious diseases in wartime Norway, such as double the amount of pneumonia deaths. It could be that the reduced heart disease numbers are simply because other diseases killed those people before they had a chance to have a fatal heart attack. This hypothesis was suggested by a researcher who analyzed 70,000 Austrian autopsy protocols and found rampant signs of heart disease in bodies whose death was attributed to infectious diseases.
Obesity
Significant percentages of American adults and children are obese, with disastrous results to physical and emotional health, and exorbitant financial costs. No traditional cultures seem to have this problem. How can we too live at a healthy weight?
The China Study’s solution to the obesity pandemic: “a WFPB diet, coupled with a reasonable amount of exercise.” It’s easy to observe how people who live this type of lifestyle are slim and vigorous. Numerous studies also support this conclusion. The evidence? First of all, a whole slew of clinical studies showing the benefits of whole food, mostly plant based diets, some of them together with exercise. Yet Dr. Campbell acknowledges that such short-term studies might offer temporary weight loss but don’t necessarily yield long-term health or even keep that weight off. Thankfully, there are also studies that show how vegetarians who eat the same or more calories as omnivores are still thinner.
Here too, it’s hard to see any proof that completely letting go of animal foods helps keep weight down.
First of all, most of the studies he mentions involved reducing animal foods, not eliminating them. And they’re all confounded by also eliminating processed and junk foods and including exercise, both of which are known to bring down weight. The China Study itself emphasizes the importance of exercise! What shred of evidence points to animal foods as part of our obesity problem, and their elimination as the solution?
The Red Pen reviewers were also quite astounded by the book’s claim that the source of protein affects weight. They even looked up the studies and found that the data collection was with unreliable methods; some didn’t even measure difference in physical activity between groups. On the other hand, there are many high-quality studies that demonstrate how the number of calories is the primary factor that determines weight, and no difference has been found in the source of the calories.
Diabetes
Another leading killer and health-care expense is diabetes, a dreadful condition with no cure that can at best be managed with drugs. Again, Dr. Campbell’s cure is the WFPB diet.
His proof begins from interpreting a study from over ninety (!) years ago that showed more diabetes in high-fat diets than high-carb ones. Similar results were found in more recent decades in a study comparing four different countries. Another study showed more diabetes in a group of “moderate” meat eating Seventh-Day Adventists than their “moderate” vegetarian fellows Adventists. Similar results were found comparing Japanese Americans with Japanese in Japan.
And so on, lots of fascinating studies that suggest something is quite wrong with our Western lifestyles but offer mighty little proof against animal foods. All the recent studies are observational, so even if a difference is found between meat eaters and vegetarians we can’t know if that’s because of the meat or that the vegetarians are more health conscious in other ways, such as avoiding processed starches. Besides that, vegetarians too eat some animal foods, so there is no evidence at all to avoid them altogether.
In this case, Campbell himself admits that such observational studies are weak proof, and therefore supplements his case with intervention studies. Yet every single study that he cites involved more than eliminating animal foods, including factors such as exercise programs or diets high in low-fat or high-fiber. Most even included at least a small amount of animal foods. Perhaps that’s why he resorts to writing in conclusion of his analyses of one of these studies: “Given these differences and based on other clinicians’ experiences and previous research, I suspect the benefits would have been larger had there been greater dietary change.” And on another one study: “Imagine what would happen if people fully adopted the healthiest diet: a whole foods, plant based diet. I strongly suspect that virtually all Type 2 diabetes cases could be prevented.”
To suggest the WFPB diet for diabetes treatment and prevention, we must rely on Dr. Campbell’s “suspicions” and “imagination”.
Cancer
The China Study’s obfuscation continues in how it treats other common Western diseases. Here is a brief outline.
For breast cancer, besides repeating the evidence from the China Study that we discussed earlier, Campbell cites a “particularly impressive” study in which female hormones were lowered in pre-puberty girls by eating “eat a diet modestly low in fat and animal-based food for seven years.”
The regular problems: they also ate less overall fat, they did eat some animal foods (with up to 150 mg of cholesterol a day), and perhaps this multi-year intervention resulted in any other confounding habits such as an overall healthier diet or more exercise. For the slight problem that they ate animal foods, Dr. Campbell again replies that he “believes” that if they had avoided them entirely then the benefits would have been “even greater.” (Didn’t he write in the beginning of the book how Hippocrates taught about science being knowing and ignorance believing to know, and therefore he’ll be telling us “what [he] has come to know”?)
In our discussion on fiber and antioxidants in the China Study, I mentioned the book’s discussion about colorectal cancer, which mostly revolved around the many high-quality studies that show much lower rates in people who eat high-fiber diets, yet somehow is spun to promote the whole WFPB plan, including the no-animal-foods part. See there for more details.
Regarding prostate cancer, the book indeed brings many studies that show a correlation with animal foods. But most implicate dairy products only, so it’s unclear if lowering risk requires eliminating all animal foods. Perhaps even dairy consumption only needs to be reduced. He also touts Dr. Ornish’s study on prostate cancer, but that important research is clearly confounded because it included stress reduction, group support, and exercise in addition to a WFPB diet. Yet somehow the book still concludes that “every doctor should tell every man with prostate cancer to stop consuming dairy immediately and embrace a WFPB diet.” It seems there may be a body of research in support of avoiding dairy, but I don’t see any evidence for the second half of the suggestion.
Because of The China Study’s intense focus on animal foods and cancer, the Red Pen reviewers looked at other observational studies, focusing on meta-analyses. They found that protein intake, whether animal or plant, didn’t correlate with colorectal, ovarian, or prostate cancer. But they did find that processed meat (not a whole food), and perhaps all red meat, have been linked with three common cancers: colorectal, breast, and lung. They also found that vegetarian and vegan diets do show a somewhat lower risk for cancer – but that might be confounded by them having other healthy lifestyle factors. These reviewers concluded that although these other studies (not mentioned in the book) might point to connection between red meat and some cancers, the book’s wide ranging incrimination of all animal foods for all cancers isn’t supported by evidence.
Autoimmune Diseases
In the chapter on autoimmune diseases, The China Study refers to lots of studies that link Type 1 diabetes with cow’s milk, and some that link it with multiple sclerosis (MS). Another researcher tried putting MS patients on a diet low in saturated fat, and for over three decades observed that the progression of the disease was greatly slowed in those who complied. That’s fascinating, but it’s hard to prove much from a trial whose control group was non-compliers! It’s not hard to imagine many other lifestyle differences between people who follow their doctor’s advice and those who don’t.
In addition, as Dr. Campbell himself observes, “low saturated fat” doesn’t mean no animal foods, and they also noticed that fish-eating areas were associated with lower rates of the disease. For this reason, the book’s conclusions here are less emphatic than usual, admitting that “more research is needed to make conclusive statements about cross-autoimmune disease similarities.” Yet the gentle undertow against animal foods is clear, when in fact the only hard evidence available implicates cow’s milk. And why doesn’t Dr. Campbell mention that there might even be a benefit from fish for this group of diseases?
Osteoporosis
Regarding bone health, The China Study cites the reams of well-known research that connect higher dairy intake with osteoporosis. Unlike what the milk industry would have us believe, eating lots of high-calcium foods might do more harm to our bones that good. Some of the studies he brings seem to have been done on all animal foods, not only dairy.
But the book isn’t clear if all animal foods were actually shown to raise risk, or that the more general studies didn’t isolate different types of animal foods, which means that dairy might still be the only culprit.
The book also provides no evidence that it’s necessary to eliminate dairy foods; it’s quite possible they are quite healthy and it’s our overuse of them that is the problem. For this problem, Dr. Campbell responds with the by-now standard “I can’t help but wonder how much greater the difference might have been had they consumed… 0-10% of their total protein from animal sources.”
Kidney Stones
But finally, as we near the end of The China Study I’m convinced about something!
The book cites research that has shown animal protein to be a prominent risk factor for kidney stones, and that reducing animal protein intake to less than one ounce seems to prevent their formation and recurrence.
So someone who has had kidney stones, or is at risk for them, might want to eat only very small amount of animal protein. But should we caution entire populations to avoid all animal foods in order to lower their risk for this single, albeit terribly painful, ailment?
Eye and Brain Health
The China Study brings the well-known research about how carotenoids, a group of antioxidants found in many fruits and vegetables, support eye health. The book also suggests that given the huge variety of these compounds, and their interactions with each other, it’s important to take them in the form of whole plant foods and not supplements. Similarly, concerning Alzheimer’s and strokes, the book brings lots of studies that mostly concern the benefits of vitamins and minerals that are found only in whole plants.
I take from this that that vision and brain health are great examples of how eating real, whole foods supports good health. There’s some good evidence that it’s healthier to eat a big vegetable salad with chicken cutlets than munching indiscriminately on donuts, hot dogs, and cookies.
That’s pretty much it for the clinical experiences. Wide ranging indeed, so I guess it’s wholistic enough. But as for building a case for against all animal foods, it’s a house of cards, as whole as it might be.
Summary – Dr. Campbell’s Three Stages of Research
Before we conclude today, let’s summarize everything we’ve learned about Dr. Campbell’s research, together his critics rejections.
In his second response to Denise Minger, Dr. Campbell succinctly outlines the development of the WFPB diet, attempting to show how all the pieces of the puzzle come together to form one seamless whole.
The first major stage of his research, Dr. Campbell’s laboratory studies, led him to suggest principles in how nutrition affects cancer growth. “These principles were so compelling that they should apply to different species, many nutrients, many cancers, and an almost unlimited list of health and disease responses.” Although he had very little data, basically that rodents fed casein after aflatoxin got more liver cancer, these findings showed him “biological plausibility” for the broad theory that the WFPB diet brings health while animal and processed foods cause disease.
The critics argue that the line connecting what he saw and what he suggested is so hopelessly tenuous that it can’t prove much of anything.
Then the China Study “permitted the testing of hypotheses and principles learned in the laboratory. By ‘testing’, I mean questioning whether any evidence existed in the China database to support a protective effect… of a plant-based diet.” Dr. Campbell openly admits here (and again several times later in his response) that he didn’t look at the China Study to see what he can find, but to verify what he already believed.
Because there was so much interplay of so much data, the China Study was a great way for him to look at nutritional patterns in a multifaceted way with numerous variables. Ultimately, he concluded that his theory was correct because of six models that worked out with his theory.
We discussed those models at length, and I’m far more convinced by his critics that none of those models incriminate animal foods as the cause of disease.
Even in Dr. Campbell’s view, the China Study findings did “not solely determine my final views expressed in the book.” They merely showed “biologically plausible data… to support the findings gained in our laboratory.” In fact, at the end of his response he admits that the only mistake he did was to agree to his publisher to call the book after the China Study, which misleadingly puts the burden of proof on this single study. Not that the China Study isn’t significant, but it’s only “very important” when examined together with “the large body of other kinds of studies discussed in the book.” Supporting evidence, but not proof.
According to the critics, The China Study’s treatment of its mistaken namesake doesn’t even reach that low bar.
Referring to the complexity of his debate with Denise Minger on the China Study data, he tellingly acknowledges that it will be hard for readers to know who to believe without access to the raw data itself. Therefore, he suggests, the strongest reason to accept his conclusions is because of the wonderful health outcomes that readers of the book and his physician colleagues have attained with the diet.
This takes us to his third and final major stage of his research: all the research and physician experiences discussed in the later parts of the book.
Unfortunately, every clinical trial was severely confounded by other dietary and lifestyle changes.
Dr. Campbell summarizes: “it was the combination of these various lines of inquiry that made so compelling the larger story told in the book, at least for me.”
It’s a large combination indeed, but if each link in the chain is broken then what conclusion can be drawn?
And so concludes our analysis of the scientific background of the WFPB diet.
Next week we’ll begin wrapping up this series by reconsidering wholism and reductionism considering everything we’ve learned in the past month.
Here’s a PDF version of this post along with all the footnotes:
