Well SkepticRD has finally got around to watching the documentary film Forks over Knives. As mentioned before I was a vegetarian for about 16 years and in that time made friends with a lot of vegetarians so I knew this movie was a big deal in a lot of people's lives when it came out. Since I've been asked about it, I finally had to sit down and watch it. I knew I had plenty to talk about after the first half hour of the film was over.
First, I think the makers of this film were counting on people not being aware of their evolutionary history. Our brains and our bodies could not have evolved into what we are today without the consumption of meat. For most of human history humans operated as a hunter gatherer society, meaning we ate only animals that were available and the vegetable matter that we could find (and sometimes some seasonal fruit and nuts) and grains and legumes simply weren't available. Agriculture has only been around about ten thousand years, which is a blip in our evolutionary history. Yes, prehistoric people may have had a shorter life span ON AVERAGE, but this average comes from people dying from being gored by an animal they were hunting or died in childbirth, not from heart disease or cancer. So, given that our bodies evolved with a heavy influence on animal protein, how could the consumption of animal protein by itself lead to heart disease and diabetes? (1, 2, 3,) I would also highly recommend the book Catching Fire: How Cooking Made us Human by Richard Wrang (not to be confused with book #2 in the Hunger Games series, ahem!).
Second, the amount of false equivalencies that were being drawn was astounding. Notice that most of the people who had poor diets mentioned that they were living on caffeine and sugar, or donuts and fast food, or sweets and meatball subs from Walmart, etc. In other words, their diets likely included meat, probably dairy, and very likely way more sugar, white flour, trans fat, nitrates, sodium, etc that the human body has evolved to handle. So very likely this contributed to their health problems like heart disease and diabetes. These people were very likely also consuming a lot of nutritionally devoid calories through their sugar, processed oils, white flour, etc so this probably contributed to their obesity. So, if people cut out their trans fat and PROCESSED oils, white flour, added sugars (including high fructose corn syrup), low fat milk, and PROCESSED meats and ate more vegetables and fruits (plants), they will get healthier. But there that doesn't mean they had to cut out all meat (what we evolved on) along with the sugar and white flour to get the same health benefits. Notice the gentleman from China grew up eating meat, just not as much as he did when he moved to the United States. So once again, there is no good evidence that meat needs to be completely thrown out.
Third, the research that presented was highly flawed and the way it was presented screamed of bias. Forcing rats to eat large amounts of casein, which rats have not evolved to eat, and they developed cancer? Not surprising. And the aflatoxin they were sensitive too? Found in corn, wheat, peanuts, and pecans--all part of a vegetarian diet. Maybe we should think about removing all the the problems? Also, human beings are not rats. Animal studies can give us something to research further, but we can't draw a direct equivalency to humans. Also, the higher incidence of liver cancer, in children in Asia that was mentioned? They forgot to mention that one of the foods introduced to Asian countries during and after WW II was processed meat, usually in the form of Spam. Chances are, those more affluent families had more access to this processed meat as opposed to the unprocessed meats the parents and grandparents would have grown up on, but this variable was not mentioned. And I really started yelling at the TV (again) when he started talking about the reduced deaths from heart disease in occupied Norway. Sure less people did die from heart disease, but there was no mention of all cause mortality. In other words, people may not have died from heart disease, but they could have died from oh, lack of food in general, lack of access to medical care, or possibly being shot or send to concentration camps by Nazi's? But we can't tell, at least from the information given here.
Fourth, there was some information that was deliberately misleading about heart disease and cholesterol. They were correct in that cholesterol is a vital component of our cell membranes and that humans do also produce cholesterol. But the cholesterol circulating in our blood stream does not come from dietary cholesterol. Forgive me for greatly simplifying a highly complicated body process here, but basically our body is smart enough to decrease cholesterol production whenever we eat it. The notion that we need to decrease dietary cholesterol if our blood cholesterol is high is based on flawed research surrounding the fact that cholesterol deposits are found in arterial plaques. And how does the cholesterol get there? If we eat in such a way as to elevate our insulin levels (i.e. take in too big of a load of carbohydrate), or eat too much trans-fat or too many omega-6 fats, or don't get enough sleep, or all of the above, we are increasing the chance of setting off an inflammatory process in our arteries. That inflammatory process basically stomps all over the inside of your arteries, and your body will have to make more cholesterol to try to plug up the potholes so to speak. So, remember how all the people with poor diets were eating a lot of added sugars, white flour, etc? And not getting enough sleep in some cases? Maybe that could have contributed to the problem? Also, I felt this film was dismissive in it's treatment of protein. It is a vital nutrient, and people who don't get enough will be malnourished. Sure, some people consume way more than they need, which might have negative consequences as far as your cancer risk, but that's not a reason to dismiss it (Dose determines the poison people!). And of course you can get protein on a vegan diet if you are able to eat legumes (including soy) and nuts, but these are not as readily available to us as animal proteins are. Remember your evolutionary biology again. Animals evolved to avoid predators by running away. Plants can't do that, so they tried to ensure the survival of their species by forming a group of chemicals collectively call anti-nutrients that can make the predator sick (like how I get when I eat gluten!) or have to go to a lot of work for the body to get to the nutrition (like all the work that goes into preparing beans so you can chew and digest them). Now, humans wind up being quite resourceful in what they will and can eat to survive, but they may not be achieving better health!
Fifth, towards the end of the film we get the classic red flag in my book, where the proponents of this diet get to talk about how they were persecuted for what they were doing and how all the money from Big Pharma and Big Agra are working against them. SkepticRD will be one of the first people to tell you that the Food Guide Pyramid, etc was also not based on good science, which will be the fodder for a whole different blog post (I have to keep you reading right?). However, using the "everybody is persecuting me" argument is not good science. Sure, there are legitimate scientists, like Louis Pasteur who were dismissed initially and later recognized for their contributions, but there are also people like Andrew Moulden who deny germ theory. If people are not being allowed to conduct legitimate research I think that is a problem, but it doesn't mean that people are somehow right because they are a lone wolf. And the woman who was asking to be taken off her diabetes medicines? That's a question I get asked a lot. If someone's blood glucose levels are now running too low unless they are eating constantly, the physician would be going against their "do no harm oath" if they didn't start removing medicine or insulin. Same thing with blood pressure medicine. If your blood glucose levels are running within the correct range and you tell your doc you want to come off the medicine, of course they are going to be hesitant, not because they are all in the hands of Big Pharma but because as good scientists they don't know if just the diet is controlling it or the diet and medicine together. A more legitimate question would be to ask "Can I go off my medicine for the next two weeks and carefully monitor my blood sugar and/or blood pressure?" That way you are getting closer to science and everyone can be happy.
This film did touch a little bit on the environmental impact of vegetarian eating and about what happens to the animals in our food system, and that it definitely worth addressing, but I will do a follow up blog post to this one to address that. For now, let's just say a vegan diet might not help like how we thought. If you do not want to eat animals at all, and I can understand why some people don't, that is fine, but you still don't really want to use flawed research to support your position, do you?
Now, I know that some of you in reader land might be thinking, "So is SkepticRD advocating for these people to go back to their previous donut/fast food/hot dogs/no vegetable diet?" Why would I do that? Why would any legitimate health care person not be happy that someone changed their lives for the better by taking responsibility for what goes in their bodies, particularly when several of the changes that they made (like avoiding processed foods) were based on good science? But what if someone did want to start including some pasture raised beef or chicken or wild-caught fish back in their diet (or never wanted to give it up in the first place)? What if, like me, they wound up intolerant to vegetarian protein sources such as legumes (including soy) and nuts? Could I tell them, that based on the use of good reasearch and knowledge human evolution that they need to avoid it? No, I cannot, not based on most of the information presented in this film.
I know, you're waiting for my take home message--yes, cutting out all the processed stuff and eating more vegetables is a good idea and there's research to back it up. Cutting out meat isn't necessary to lose weight and lower your cholesterol, inflammation, risk of heart disease, or risk of cancer according to better done research.