The title of this article might seem to focus on two 'fringe' diets, but this question is actually at the root of a lot of current nutrition debate, because what it really boils down to is this: which is healthier, meat or plants?
Last year I went to a so-called 'nutrition science' debate in New York. The debate centered on the question of whether or not a diet that includes animal protein and fat could be as healthy as a 90% plant based diet. The parameters of the debate prohibited the debaters from including processed foods, refined grains and sugar heavy foods from the discussion. It was supposed to center only on the idea of animal vs. plant.
Shortly there after, Dr. Dean Ornish wrote a piece in the New York Times in response to the new Dietary Guidelines' suggestion that we remove the dietary restriction on cholesterol. Dr. Ornish's article also focuses on one central idea, plants are healthier than meat. (If you want a very clear breakdown of how Dr. Ornish's article is flawed check out Dr. Michael Eades' brilliant rebuttal.)
And last Fall, as I’m sure many of you are aware, the WHO released a report that prompted many hyperbolic and fear inducing newspaper headlines about the “dangers” of eating red meat – even though the study was only “conclusive” regarding processed meats.
It seems like every few months there is a smattering of “new evidence” that “red meat will kill you” or some “new study” extolling the benefits of eating a diet that is primarily plant based.
These issues are even present in basic nutrition textbooks. In reading about how peer pressure effects nutrition in adolescents one textbook says "In some cases, choices based on peer pressure can lead to improved dietary intake, such as reduced intake of animal protein due to animal welfare concerns or choosing food with a lower carbon footprint. In other cases, the choices based on peer pressure may lead to poor dietary intake, such as consumption of fast foods, convenience foods, sweetened beverages, and other highly processed foods that are high in added fats and sugars." This one is especially tricky because the first sentence clearly takes the stance that plants are healthier than animals and then further confuses the matter by calling out highly processed foods as poor dietary choices in the next sentence. This language, as is often the case, confuses the issue even more because it's not plant vs. animal; it's plant vs. animal + fast food + convince foods + sweetened beverages + other highly processed foods that are high in added fats and sugars. And there is the issue.
These debates and articles are centered around a straw man argument. They create a conflict over an issue that shouldn't really be the focus - why are we debating meat vs plant when somewhere between 60% to 75% of US food consumption is processed? This can be processed meat or processed plants.
We are omnivores. We evolved to eat plants and animals; it's part of why our species survived when others didn't. The proportions of our diet that should be plants or animals shouldn't even be debated because humans are able to adapt and thrive on a wide range of diet patterns, so long as we are eating whole plants and whole animals.
Currently, there does not exist a way to accurately and definitively test a single dietary component’s direct impact on long term health as it relates to the development of chronic diseases. Nutritional science first started cutting its teeth because of specific diseases that had very obvious, very direct links to specific components of the diet - a diet deficient in vitamin C caused scurvy, a diet deficient in niacin caused pellagra, a diet deficient in thiamine caused beriberi. These are diseases that were eventually found to have a direct link to specific nutrients in a diet. Those discoveries were long and difficult on the one hand and really easy on the other. It took a long time to finally figure out that diet had an impact on disease; many other theories were proposed for all of the above mentioned diseases, but once the vitamin deficiency was identified the results were quick and undeniable. Specific nutrient, specific deficiency, specific disease. Correct the nutrient, reverse the disease.
This is how we want nutrition to work as a whole. Specific nutrient, specific deficiency (or excess), specific disease. But that's not the way it works. We know that diet has a huge impact on our health. We know that certain chronic disease states are on the rise. And that's it. There is no way to definitively link one to the other. We are no longer talking about a direct link where one factor has a direct impact; we are now in a multifactorial system.
But that doesn't mean that we should throw up our hands in frustration. It means that we should understand the limits of the field of “nutritional science.” We should look at bigger picture shifts, not just specific nutrient changes. Is it the saturated fat in our diet or the sugar? Maybe both, possibly neither, but doesn't our consumption of processed food as a whole greatly outstrip our increased consumption of either one? You can quote numbers until you are blue in face regarding whether or not we consume more carbohydrates or animal products now than we did 40 years ago or 70 or 100. But can anyone deny that we are consuming more processed foods as a whole?
Let's stop looking for a specific nutritional marker for why the Standard American Diet brings health problems wherever it goes, because the problem isn't one component, it is the overall diet composition shift from real, whole foods to processed 'food like stuff.' Perhaps there is some as yet to be determined component of food that directly causes any number of long term chronic diseases, but until we figure that out, shouldn't we have a consistent message based on what we do know - that for some reason a diet high in processed food seems to be associated with an increased prevalence of several long term chronic diseases?
At this point we shouldn't be focused on whether or not a diet high in animal protein and fat is more or less healthy than a diet that is 90% plant based, there are bigger fish to fry (or eggplants, if you prefer). If we all seem to agree that highly processed food isn't good for us, instead of arguing over plants vs. animals, shouldn't we be joining forces to spread the message that a diet based on real, whole food is the healthiest? Let's save the debate over the specifics until we are actually eating plants and animals, and not plant and animal derived products.
If you only take away one thing, it should be this question: Why are we debating meat vs plant when somewhere between 60% to 75% of US food consumption is processed?