Forks Over Knives presents the audience with the argument that a whole-foods, plant-based diet with no meat or animal products or refined foods is the way to a long, healthy, cancer-resistant, and heart-disease-free life. Forks Over Knives plays like a 1950s governmental instructional video, makes basic reasoning mistakes, and discredits itself by touting examples that no skeptical audience can take seriously.
Before we go any further, let’s cover the things that basically all nutritionists, doctors, and scientists can agree on. When discussing the movie’s content, I will be starting from these as basic assumptions. Vegetables are good for human beings. Fruits are no slouch either. Both in pure volume and as a proportion of one’s overall food consumption, eating large quantities of refined sugar is harmful to the body. Consuming disproportionately high levels of foods high in calories and low in nutrition (for example, eating a fast food meal and no veggies or fruit most days) can cause health problems. The spread of obesity in America needs to be addressed through concerted educational efforts and a reorientation of people to their food. Before anyone gets any ideas about throwing a beet-related tantrum or trying to frame this review as advocating that we all eat a cow a week—just don’t.
I generally do not discuss the plot of an entire film in a review to avoid spoiling a movie for my readers. In documentaries, I try to look into the facts and outline the arguments. If this is an issue for you, this would be a good time to stop reading and scroll to the last two paragraphs, in which I give my general summary.
Forks Over Knives makes these assertions ad nauseum through the entire movie:
- A whole-foods (not refined), plant-based diet is the best for people.
- It prevents and can reverse cancer and heart disease.
- Meat, animal products, refined foods (including sugar and oil), and high levels of protein cause and/or contribute to cancer and heart disease.
They assert that animal proteins, both muscle and byproduct, are harmful. This includes meat, dairy, and other animal products. The doctors in the movie contend that the high concentration of protein in milk feeds cancer and tears away endothelial cells in blood vessels, making a person more vulnerable to heart disease. Huh? That is a pretty radical claim to make without outstanding evidence. Luckily for us they did set out to provide us with evidence—or should I say “evidence”?
The foundation for the conclusions presented in Forks Over Knives is built by Cornell University professor T. Colin Campbell, PhD, and Caldwell B. Esselstyn, MD, of the Cleveland Clinic. Campbell conducted several studies and research experiments outlined in the book. Esselstyn treated and continues to treat some of his patients with strict changes in diet.
Campbell explains a study he conducted on rats examining different concentrations of casein, the main protein found in milk, in which he found that different concentrations resulted in different cancer rates. 20 percent casein rates resulted in higher rates of cancer than 5 percent casein rates. Based on that and an observational study of Filipino families, he launched a humongous study of the diet of rural Chinese people and wrote a book, The Diet, Life-style, and Mortality in China: A Study of the Characteristics of 65 Chinese Counties, by Chen Junshi, T. Colin Campbell, Li Janyao, and Richard Peto. After examining over 300 factors of thousands of people, he concluded that a whole-foods, plant-based diet is best and eating meat or animal products is bad because it causes cancer.
After examining information about heart disease rates in Kenya and Papua New Guinea against the rates in America, and after conducting numerous bypass surgeries, Esselstyn decided to conduct a small study of fewer than twenty-five people to change their diet to plant-based whole-foods with small amounts of dairy. Of the people who stayed in the study, all survived much longer than was expected (many were close to death because of severe cases of heart disease). He continued the study and now has treated 250 people using the diet.
I am not a scientist, nor am I a member of the medical field (unless lifeguarding as a teenager counts), but I spotted some serious problems with the reasoning here. Campbell equates all animal proteins to casein; furthermore, he does not explain how he came to his conclusion that animal protein and products are bad for people based on results from the people in China.
Esselstyn compares heart disease rates in Kenya and Papua New Guinea to rates in the United States, and assumes the discrepancy is based on diet and that inhabitants of Kenya and Papua New Guinea do not eat meat. Besides the lower standard of medical care in those countries, which makes the assertion of any accurate numbers impossible, the life expectancy is so much lower (Kenya 58 yrs, Papua New Guinea 57 yrs) compared to America (78 yrs), it is impossible to directly compare.
If a person who might get heart disease in his 60s in Kenya dies from AIDS at age 32, this says nothing about his risk of heart disease at 65 years. If that Kenyan does live to age 57, but has no access to medical care and is never diagnosed, his medical condition can never be recorded, and he lives in a country that probably does not keep complete statistical records.
It can hardly be considered a proper comparison, with similar enough variables to be able to examine the relationship between the two countries conclusively or effectively. It certainly cannot be concluded that diet is the reason why Kenyans or the people of Papua New Guinea do not have heart disease. Using his same analysis method I could attribute the United States’ lower HIV/AIDS rates to our highly processed, high-sugar, meat-centered diet.
His initial study, which concluded with only eighteen people, could hardly be considered a representative sample of anything other than those eighteen people. Even his expanded patient sample of two hundred fifty people is no more representative. He also disregards the people who did not comply with the diet, even though ability to adhere to a nutritional treatment is a necessary consideration. We could all cut down our risk of heart disease if we only ate carrots dipped in potato mush, but I doubt many people would comply, and it could not be considered a viable or successful treatment.
Esselstyn’s conclusions force him to jump over sedans, but Campbell has to go full Evel Knievel, jumping sixteen school busses before sailing over the Grand Canyon, bouncing off a trampoline, and landing on his front tire on a dime sized target.
I do not remember how many proteins there are, are but I do remember from high school biology that there is more than one kind of protein. Drawing the conclusion or even starting to examine the possibility that all animal proteins are harmful to human beings based on the potential cancer-causing properties of different concentrations of one type of protein in rats is complete hooey.
Forks Over Knives does not go into the specific data of Diet, Life-style, and Mortality in China other than to state that Campbell feels it conclusively proves that a whole-foods, plant-based diet with no meat or animal products prevents cancer. Again, I am no expert in the authentic Chinese culinary techniques, styles, or food, but I do know that the Chinese diet does not fit the Campbell-approved diet. While he is correct that the Chinese do eat a far more plant-based diet than we do, the Chinese diet includes small amounts of meat.
The thesis, argument, and attempts to rebut the objections were just adding up for me. I thought that maybe because it was in movie format that important pieces of information were missing. Certainly the doctors would not present their point of view without having some sort of rational basis. These two are no schlubs when it comes to their credentials. I decided to investigate the essential claim presented in the movie as best I could. I tried to fairly examine supporting and critical papers, essays, and comments.
Both doctors said that examining the results of the study proved conclusively that a whole-foods, plant-based diet with no animal products helps prevent cancer. Esselstyn extends that claim to heart disease.
It turns out, not so much. The study was huge, and did take into account a large number of factors, but was completely observational; of the eight thousand correlations, no causation could be established. One of the criticisms I read points out this very glaring problem; in a later book by Campbell for general consumption, called The China Study, he writes on page 107:
“At the end of the day, the strength and consistency of the majority of the evidence is enough to draw valid conclusions. Namely, whole plant-based foods are beneficial, and animal-based foods are not.”
Just an inch lower on the page:
“The China Study was an important milestone in my thinking. Standing alone, it does not prove that diet causes disease.” [italics in the original]
Did you hear that? It was the sound of Campbell attempting that bus-canyon-trampoline jump I mentioned earlier. In Forks Over Knives, he not only attempts to get us to eat more veggies and less meat, but tries to get us to eat no meat because it causes cancer and heart disease and eating only a whole-foods, plant-based diet would prevent these diseases. Yet even Campbell says that he cannot draw that conclusion from this study even though he says earlier that that conclusion can be drawn.
Online Campbell refutes that his dietary recommendations were based exclusively on the studies he mentions in the film. Unfortunately, if audience members do not research the claims made in the film, there is no way for them to know about the additional factors that Campbell says he used to draw his conclusions.
The film briefly mentions a study done in Norway during World War II. It concluded that people had fewer heart attacks during the time the country was occupied by Germany. The Germans took the livestock for their soldiers, so Norwegians had to move to a plant-based diet. Unfortunately, when one goes from grazing animals in their yard to farming, it requires different levels of activity. There may have also been other things that were and were not available during this time—both food and environmental factors. The doctors do not bother to outline any of these other potential variables.
Esselstyn mentions in passing that he puts his patients on statin medications when he is describing the study he created; that is the only mention of these drugs that he gives, and only in passing. He does not have a full diet treatment; he leaves that to a couple other doctors in the movie, Matthew Lederman, MD, and Alona Pulde, MD.
Lederman and Pulde, who run Exsalus Health and Wellness Center in Los Angeles, are two doctors featured treating patients in Forks Over Knives. In the film it is implied they treat people with food instead of medicine. They take a patient featured in the movie off of his medication and they show the doctors shopping with this patient for new food. There is no discussion of any other factors besides diet.
The front page of the Exsalus Health and Wellness Center’s website paints a slightly different picture.
“Exsalus Health & Wellness Center is comprised of a group of medical doctors committed to maximizing the health of our patients. Using a comprehensive, patient-centered approach that includes medical evaluation, nutrition education, practical lifestyle application, acupuncture, massage, and physical fitness we help our patients achieve optimum health.”
The problem here is not that they get people to relax, de-stress, exercise, and eat better. Heck, those are things we can all agree are good for people. The problem is that when they speak in the film, they only talk about diet. It is sort of like cleaning a house using a vacuum, broom, and paper towels but saying that the reason why the house is so clean is the awesome paper towels. We could chalk this up to editing problems if it happened once, but it did not.
The narrator and writer of the film, Lee Fulkerson, decides to try out the treatment from Lederman and Pulde. Right before entering their office, he explains that he is not the kind of person we would expect to do this treatment because he has just consumed two Red Bulls (a high-caffeine energy drink). When he goes into the office they do a health evaluation, including blood pressure and heart rates. When he returns after doing the diet, his numbers are much better.
Each 8.3 oz bottle of Red Bull has 76 milligrams of caffeine or a total of 152 milligrams of caffeine. WebMD explains the effects of caffeine:
“Caffeine works by stimulating the central nervous system (CNS), heart, muscles, and the centers that control blood pressure. Caffeine can raise blood pressure, but might not have this effect in people who use it all the time…”
It is possible that drinking two energy drinks before going to the doctor to have a physical will not affect your heart rate and blood pressure. It is not probable that stimulant drinks had nothing to do with the measured improvements. I find it impossible to consider the physical improvements of this diet based on the measurements because the measurements taken were not valid.
In fact, there is little discussion about the other factors that may cause people in China, Kenya, Papua New Guinea, and Norway in World War II to have different health outcomes; most notably and egregiously is the complete silence on physical activity. Exercise is never a topic for discussion, even though almost all of the people on the diet in the movie are at some point shown exercising. Average physical activity levels in China, Kenya, Papua New Guinea, and Norway are all extremely different from those in the United States. A discussion about modifying diet without modifying activity to fight heart disease and cancer is like trying to bail out a boat without plugging the hole.
Forks Over Knives slips in an assertion as fact that I found pretty shocking: 1–2 percent of cancers are hereditary. It was my understanding that the scientific community had not yet found or pinpointed the cause of most cancers. There is no source sited, and I did try to find the reference but I could not find it. I guess it happened so long ago it is not on the Internet?
As if it was not bad enough that the argument they try to present has evidentiary problems, it is riddled with logical fallacies and quackery warning signs. At one point Campbell is swarmed to sign books, like a rock star giving out autographs. There are appeals to ancient wisdom, celebrity endorsements (ok, celebrity-ish), deceptive framing of opposing arguments, visual cues meant to sway emotion, direct appeals to emotion, and appeals to fear, and I have not even gotten through the first half hour.
Their most blatant and shameless appeal was to the ego of the men in the audience. They go out of their way to prove how manly their diet is, with a Mixed Martial Arts fighter, a fireman chanting that “real mean eat vegetables,” and even discussions about how well the penises of Esselstyn’s patients work. No, I am not exaggerating.
Oh, and the C word does make an appearance. Not the offensive one describing a woman, no. The big one, the skeptic’s big C: Cure.
It also frustrates me that the doctors did not use the common term for their diet: vegan. (It is only said two or three times in the entire movie, by the MMA fighter.) It is a loaded word, but if the film wants me to wear a label, it had better tell me what that label is, and why I should take the flak. To avoid it altogether is at best cowardice and at worst deceptive.
The movie is not without some interesting factoids. It also spends a little bit of time explaining the conflicts involved in USDA policy-making. No agency can advocate for and simultaneously regulate the same industry. The most horrifying example is the food that one can eat and be in compliance with the nutritional guidelines as outlined by the USDA. A young person could eat a bowl of Lucky Charms, a burger and fries, and a slice of pizza in the same day without deviating from the guidelines. Yuck.
Forks Over Knives is not even entertaining or well made. The editing has serious issues. The style in which it is shot seems cheap. There is little to keep the attention of anyone who does not already agree. It is not a total snore, but then I did have a lot of coffee before I went.
I could continue for another hundred pages about the problems in the film, the deceptive way it frames the arguments it makes, the inadequacies of the arguments, or the bore factor. Based solely on what the doctors offer in the film, I was not convinced that a whole-foods, plant-based diet can cure cancer or heart disease. Based on my research into what they offer, I was even less convinced.
Forks Over Knives reminds me of a quote by Douglas Adams: “Isn’t it enough to see that a garden is beautiful without having to believe that there are fairies at the bottom of it too?” Isn’t it enough to tout the health benefits of whole plant foods without creating a false demon of meat and dairy?
Note: I only saw this movie once, and did my best to take complete notes and verify what was said on the website. If I have missed something, or have misunderstood something, please let me know.
Matthew Lederman, MD, and Alona Pulde, MD
Exsalus Health and Wellness Center, Los Angeles, California