I write this article today because I see so many people out there struggling to grasp what it means to eat healthy. I see so many people who have good intentions to start eating better foods, but get fed up when they hear things like, “you can’t eat meat,” or “eating eggs and bacon is going to kill you.” The worst is when I hear people that think that they have to give up meat to be healthy, which they refuse to do, so they won’t even bother with any of the health stuff.
It may very well be that the meat, milk, and cheese you are currently eating is killing you. But probably not for the reasons you think. Shifting to a healthy eating pattern will likely involve switching out some meat-based foods, but it does not have to involve cutting out all animal foods. Now the question is, how do we figure out which ones are okay to eat??
Today I’m here to help sort this mess out. I’ve done some digging, some thinking, more digging and more thinking, and …
I’ve decided that to answer it, we’ll need to invoke the good old scientific method. Remember that process – the one you learned about in high school biology? Well I think it’s time we bring it back into the picture. To do so, I created an hypothesis, from which I created a null hypothesis , and have set out to see if it can be proven wrong, as is done in hypothesis testing (If you’re unfamiliar with the method, you can simply google hypothesis testing). Along this journey, look for these key points:
- When, why, and how animal consumption is dangerous.
- When, why, and how animal consumption is beneficial.
- What exactly is it about animal consumption that causes disease.
Forming a Hypothesis on Animal Products and Disease
Let’s start with a very basic hypothesis: consuming animal-based foods causes disease. This hypothesis is based off the observation that those who eat animals tend to get sicker than those who don’t. I didn’t have to dig too deeply to find some studies supporting this hypothesis. Go to your library, look in the nutrition section, pick a book at random, and there is a good chance that you have in your hands a guide to why you shouldn’t eat meat. In case you are unfamiliar, here are some cases:
One of the most famous books, written by one of the most prominent figures in the field, is Dr. Colin T. Campbell’s The China Study. This book is particularly compelling because it is based off of large population studies, with a focus on rural Chinese populations, from which the data showed one clear message: there is a strong association between consumption of animal foods and increased rates of disease. If you want to find a whole book documenting cases of associations between animal consumption and disease, this is a good one to start with. Pick a disease, and chances are Campbell documented a case where consuming animals was linked to it. To name a few of these positive correlations:
- Heart disease and percent of total calories coming from animal protein; R=.64
- Meat consumption and colon cancer incidence
- Cow’s milk consumption and incidence of Type 1 Diabetes
Again, this is only a snapshot of the data, and if you are doubtful that it means anything, I highly suggest you check out the study.
Now let’s look at a more specific, more recent case on animal consumption and disease. In a 2017 study of 536,969 AARP members aged 50-71 the researchers found that, “An increased risk of all cause mortality… and death due to nine different causes associated with red meat intake was observed. Both processed and unprocessed red meat intakes were associated with all cause and cause specific mortality” (1). So here’s another study examining over 500,000 people, showing that once again, red meat is strongly associated with disease.
Now, anyone that knows an ounce of how science works should immediately understand that these findings don’t mean much – not until tests showing a causal link are performed. Epidemiological studies are a good starting place to form observations, but unless we can conduct controlled studies to uncover mechanisms that show why animal consumption causes disease, then these association-based studies are dangerously misleading. That doesn’t mean that these findings aren’t important, but rather that the data needs to be explored much more thoroughly before any conclusions are formed.
Of course, many follow-up studies have been performed, and digging into these offers many interesting findings. I’ll stick with some of the most well-documented means by which consumption of animals causes disease.
How Consumption of Animal-based Foods Causes Disease
Below I’ve listed out a few of the mechanisms by which animal foods have been shown to cause disease. The corresponding descriptions are only brief introductions, as the data supporting all these findings is vast. I’ll provide you with some links where you can find more information on the subject, if interested.
1. Cortisol: the body’s stress hormone
We all have heard about the dangerous effects of stress. Along with diet and sedentary behavior, it is arguably one of the main reasons for the incredible rates of disease seen today. Chronic stress is dangerous because cortisol, the body’s stress hormone, does a great amount of damage when raised for long periods of time. Well, it turns out that consuming too much meat leads to the same result: increased levels of cortisol (2).
2. Inflammation:
Animal-based foods are strongly linked to inflammation via a number of mechanisms. Just google inflammation and meat, and you’ll have enough reading for the month. Inflammation is another one of those terms popping up everywhere, and rightly so, because inflammation is a major cause, or amplifier, of most of our common chronic diseases.
Again, the amount of information on this topic is overwhelming, but the general idea is that consumption of processed, over-cooked, or large quantities of meat, raises inflammatory markers such as CRP, TNF-a, and IL-6 (2). This article was particularly interesting because it examined processed and non-processed meat and inflammation, and showed all three of these markers increase with meat consumption. (If you do examine this study, please note the amount of protein labeled “high-protein” was 4 g/kg body weight, which is about 4 times more protein than is generally recommended).
Another couple mechanisms by which animal-based foods cause disease are via a couple molecules, TMAO and IGF-1.
TMAO is another interesting molecule that is involved in many of our main killers, including heart disease. Research on this molecule began when studies showed higher levels of TMAO in those that ate more animal-based foods. Diving into the research, it turns out the TMAO is created when certain gut microbes convert choline. While choline is generally seen as a molecule with many health benefits, when certain gut microbes are present, as they tend to be in meat-eaters, the choline gets converted to a dangerous compound, TMAO. This compound is then free to circulate the body, causing problems such as kidney damage, as well as increasing the rate of plaque formation in the arteries.
In my opinion, IGF-1 is one of the most concerning markers linked to animal-based food consumption, because of its strong link to many forms of cancer, particularly prostate cancer (6). It turns out that is is the high levels of animal protein that cause the rise in IGF-1, and therefore it follows that those that consume lots of meat are likely at a higher risk of cancer. Dr. Furhman, whom I’ll discuss later, is a great source for more info regarding IGF-1.
(one note here, it turns out that low levels of IGF-1 can also be dangerous, as low levels are also linked to higher mortality; this points to an optimal level of IGF-1, where levels that are too high or too low can be dangerous (6)).
Unfortunately, this is just the tip of the ice burg with all the problems animal-foods can cause. There are also problems with the iron found in meat (heme iron), along with all the other things that come along with industrial meat (hormones, antibiotics, viruses, bacteria, etc.).
Testing our Hypothesis
There you have it. Consuming animal-based foods is unhealthy because it increases inflammatory markers, promotes cancer growth, promotes a stress response, and much, much more. Now it makes sense why all those epidemiological studies showed correlations between animal foods and disease! So are we done, should we all stop eating meat yet?
Hold on before you form an answer, because we’re only getting started along this process. We still have to perform other components of hypothesis testing before we can reach any conclusions.
A key factor of a strong hypothesis is its ability to predict outcomes. If this hypothesis were true, we should be able to make predictions about those that eat animals vs. those that don’t. Consumption of animals makes us sick, so those that stop consuming animals should be healthier. Is this true?
Thankfully, we have many data points for this exact scenario. If we look at the vegan community, the population that has done this very thing, we find that the answer is… absolutely!
The superb health of vegans is well-documented. (Note here, I am thinking of vegans that consume a whole foods plant-based diet; I am not thinking of the vegans that happily live off of potato chips and oreos).
I’ll discuss Dr. Joel Furhman today, because I think he has the best grasp on what a healthy vegan diet should consist of. Also importantly, he has written books on his experience with individuals who have adopted a whole plant foods diet. We all know that plants are incredibly healthy for us. If you want to know exactly why, check out his work. However, for today, I just wish to dive into some of his clinical work.
His diet, which he has coined the nutritarian diet, is based off the idea that optimizing health involves optimizing nutrient density (i.e. the ratio of nutrients to calories). Because plants are generally very high in nutrients and very low in calories, they have the best nutrient densities, and therefore we should load up on these. This naturally means getting rid of animal foods, which are higher in calories due to their fat content. Makes sense, right?
And indeed, he has achieved great success applying this diet framework. One study he conducted of the Nutrient-Dense, Plant-Rich” diet showed:
Compliance of greater than 80% with the target diet resulted in an average sustained weight loss of over 50 pounds in 75 obese subjects. There was a corresponding average reduction of 27.8 mm Hg in systolic blood pressure for the 127 survey responders with untreated hypertension at baseline, and a 42.2 mg/dL average decrease in low-density lipoprotein cholesterol for the 328 survey responders, not on cholesterol reducing medications.”
Here, with this one case, we see that shifting to a diet high in plants and void of animals makes people healthier. For many individual cases of success with his specific vegan diet, you can check out his website.
Is it time to go vegan?
Great, so now we’ve established that consumption of animals tends to make people sicker, and that by shifting to a plant-based diet, we can become healthier! We have a strongly supported hypothesis, that eating animal-based foods makes people sick, and we can use it to make predictions. Cool, so case closed? Should we all become vegans now?
You could, and many argue that the evidence presented is strong enough to rid ourselves of all animal-based food consumption. I’m not here to argue that it’s a bad idea. If you’re happy eating only plant-based foods, and know you are willing to eat enough of them to get enough nutrition, then by all means – go be a vegan.
However, I will argue that it is worth continuing along with this process. While there is substantial evidence supporting a vegan lifestyle for great health, that’s not the hypothesis we’re testing. We’re testing whether animal-based foods are dangerous, and should be avoided entirely. So far this hypothesis has been supported by loads of evidence. The thing is, hypothesis testing isn’t supposed to involve trying to support a hypothesis – rather, we build a hypothesis and then try to prove it false. This may sound funky, but it is the key to creating strong, valid theories.
It is easy to find data to support most hypotheses. But uncovering real, scientific truths requires that no data conflicts with the hypothesis. More specifically, in hypothesis testing, we don’t try to prove a hypothesis. We see if we can disprove the null-hypothesis. If the null-hypothesis is supported by evidence, then the hypothesis needs to be reshaped to incorporate the data. If any data says something is contrary to the hypothesis, then how could it be a scientific truth?
It looks like this. We have a hypothesis:
Hypothesis: consuming animal-based foods causes disease.
To test it, we don’t want to find a whole bunch of data to support it; rather, we must make a null-hypothesis, and disprove that:
Null-hypothesis: consuming animal-based foods does not make humans sick
If the null-hypothesis continuously gets disproved, given plenty of data supporting the hypothesis, then we can start to confidently believe the hypothesis. But if the null-hypothesis is ever supported by any data, these hypotheses must be reshaped to incorporate that data.
For example, gravity is a scientifically proven theory. The hypothesis, that all objects with mass exhibit a force on one another, has been thoroughly vetted. If you throw an object up, it will always be pulled back to Earth. The null-hypothesis, which has been disproved, is that an object thrown into the air does not get pulled back to Earth (of course, in the absence of all other forces). We know the theory of gravity is valid because the null-hypothesis has never been supported. No matter how many times objects get thrown into the air, they always come back down.
Is it the same case with this hypothesis I’m testing today? Has the null-hypothesis ever been supported? Have consuming lots of animal-based foods ever not made humans sick? Or even more extreme, have consuming lots of animal-based foods ever led to superb health?
This is my key point here, so pay attention. The thing is, we don’t need to do any fancy studies to support this null-hypothesis. Just look at all the people living today that thrive off of diets heavy in meat, dairy, and eggs. Better yet, we can examine all of our ancestors that lived for millenia, with animals as a prized source of nutrition. We don’t have to make the argument that they had superb health, free of these chronic diseases plaguing us today (although there is plenty of evidence for that argument). No, today, all we need to do is understand that our species spent millions of years surviving on these foods, and they didn’t have high rates of chronic disease. Rather, they had extremely low rates of these diseases. Therefore, it seems absolutely illogical to say that these same foods are the reason we get sick.
To support this logical assumption that animal products are not inherently the cause of chronic disease, let’s look into the data. Now, because there aren’t generally studies conducted where people examine whether eating meat didn’t kill people, let’s go one step further and look at some studies where eating more animal-based foods led to greater health.
One such area with success with diets rich in animal fats is in treating diabetes. The Low Carb High Fat (LCHF) diet is breaking ground as a promising diet for treatment, and possibly even reversal, of diabetes. If you’ve been paying attention to the world, you’ll notice that diabetes is one disease that gets much attention for being caused by high fat, animal-based diets. Well, it turns out that these exact diets are actually great at treating diabetes!
One recent paper by many of the leaders of the LCHF diet demonstrates the power of this diet (3). In this study 262 people were put on a high fat diet (238 completed the trial). They were counseled to restrict carbs, moderate protein, and eat fat to satisfaction. Note that a high fat diet doesn’t necessarily have to include animal-fats, but it most often does. They found that: “Early results demonstrate markedly improved glycemic control with less medication and modest changes in blood pressure, total white blood cell count, and liver and kidney functions.”
Now this makes a lot of sense. Type II Diabetes is a disease of glucose intolerance. Therefore, it seems logical to eat much more fat (animal foods), as opposed to carbohydrates, which the body can’t handle. I’ll have much more to say on this topic down the road.
For now, if you want more information on why LCHF works so well to reverse these chronic diseases, look into some of the work done by these authors, many of which are some of the leading experts in the field. For example, you can check out Dr. Sarah Hallberg’s Ted Talk, or some of her other videos on YouTube, where she discusses her success with her clinical work.
A similar way that animal foods are great for health is through their ability to promote weight loss. Excess body weight is a major risk factor for almost all chronic disease, due to the many problems that arise from excess lipids stored and floating around the body. Sufficient evidence has piled up to show that this same diet, one high in fat and moderate in protein, which most often contains whopping amounts of animal-based foods, is great for weight loss (4). In my series on weight loss I dive into exactly why, so you if you’re interested in more information I encourage you to check out those articles.
The ability of the LCHF diet to help people lose weight and overcome chronic diseases, like Type II Diabetes, shines light on the idea that adding more animal derived fats like whole fat milk, cream, eggs, and cheese, could lead to greater weight loss, thus decreasing risk for almost all chronic disease.
I’ll also take a moment to acknowledge some of the powers of animal fats to cure disease, historically.
In the introduction to animal fats in her book Nourishing Fats, Sally Fallon Morrel discusses how animal foods, particularly the fatty ones, were often prescribed to overcome serious diseases in children, including “infectious disease, rickets, anemia, and growth problems.” The problems, “rightly attributed to poor nutrition,” were overcome by consuming, 80 percent more (whole) milk, 55 percent more eggs, 40 percent more butter, and 30 percent more meat.” She also discusses the incredible powers of other fatty animal foods, such as cod liver oil, which was commonly prescribed because of its high nutrient content and superb fatty acid profile.
The takeaway here is simply that cases like these support our null-hypothesis. Animal foods are just as capable of making people healthier as they have been shown to make people sick.
As I did previously, with examining how animal-based foods make people sick, let’s dive into some specific mechanisms for how these foods make humans healthy!
Understanding Why Animal-Based Foods Improve Health
If you have been around long enough, or otherwise have heard some stories from your grandparents, you’ll remember that once upon a time, animal foods were touted for their health benefits. People were once prescribed to eat more animal foods, which were actually great at curing nutrient-deficiencies. However, all that changed when cholesterol and saturated fat got demonized in the 50′ – 70’s, and all of a sudden consuming fat became the surest way to give yourself an early death. Now that stronger studies have shown that fears of fat are unfounded, we need to get back to remembering the many nutritious properties of these animal foods.
Animal fats contain loads of fat-soluble nutrients that the body needs to function. Animal fats contain high levels of bioactive forms of vitamins A, D, and K. Yes, you can get these vitamins elsewhere, but to get them in the most natural, and therefore most useful form, you can just get them from other animals!
Not to forget that animal fats themselves are great energy sources. Take butter, for example. It has gotten a bad rep because of its saturated fat content, although butter is actually around 1/3 oleic acid – yes, that’s a monounsaturated fat, the one everyone agrees is healthy. Additionally, it contains an assortment of fatty acids, including short and medium chain fatty acids, which have many beneficial properties. For example, as Morrel explains in her chapter on butter as the “queen of all fats,” these short and medium chain fatty acids get used directly for energy by the body and don’t get stored, “so they are ideal for weight loss.” Furthermore, she explains how these fatty acids “stimulate the immune system and support intercellular communication… [and] have microbial properties, killing pathogens including candida in the gut.” If you’re still afraid of butter because some of the fats in it might rise LDL, I highly consider researching the full fatty-acid profile of this marvelous food, to get a better picture of the many ways it affects the body.
And that’s only the fats! An extremely nutritious component of the animal that is making a comeback is the bone and connective tissue. Consuming these, generally in the form of bone broth, or by cooking with the bones left in place, allows us to take in all the important molecules that make up our own bones and connective tissue. One important component that I’ve been working on adding into my diet is collagen. Collagen a major component of connective tissue, and you can only get it from consuming animal foods. Again, we can make it from plant foods, but it is much more efficient to consume it in its already made form.
Back to Hypotheses Testing
So here’s where we’re at: this null-hypothesis that consuming animal-based foods does not make humans sick gets supported just as often as the hypothesis does. Just like it is easy to point to the whole vegan population that’s demonstrating how plant-based diets are healthy, I can just as easily point to the paleo and keto crowds to show how consuming animals can be healthy. If the hypothesis is that animal foods made us sick is valid, then populations, such as the paleo folk, should have some of the highest rates of disease. Plus, our species probably would have died out long time ago – or we would of at least seen high rates of diseases like heart disease. But this isn’t true! For every case of someone ditching animal-based foods for plants to achieve great health, there are just as any cases of people eating more animal foods while maintaining great health.
If animal-based foods were responsible for chronic diseases such as diabetes and heart disease, then these diseases wouldn’t be so novel, with mass amounts of cases popping up only within the last century. Therefore there has to be something else – something that is different with the animal-based foods that we consume today that cause disease, as opposed to animal-based foods traditionally eaten that did not.
Let’s quickly review some of the data:
- Based on epidemiological studies, eating animals tends to make the population sicker. Moreover, we understand specific mechanisms for which this occurs (e.g. TMAO and IGF).
- However, the hypothesis that animal consumption causes disease does not hold up, because many people and populations do eat plenty of these foods, yet thrive health-wise. Not to mention the fact that we evolved consuming animals.
- Animal fats are great sources of nutrients, such as vitamins A, D, and K. Moreover, the fats themselves are crucial for the body’s functioning
As I stated previously, if any data conflicts with the hypothesis, the hypothesis must be tuned to incorporate the data. Using the information we’ve explored to tune the hypothesis:
Old hypothesis: The consumption of animal-based foods causes disease.
New hypothesis: The consumption of animals is not inherently dangerous to human health; rather, the consumption of animals from the industrial food chain causes disease.
This new hypothesis is based off a few key ideas. First, we know beyond any reasonable doubt that the way in which animals are consumed today causes disease. Second, the way that animals were traditionally consumed did not cause these problems, because the rates of chronic disease were minuscule compared to rates seen today.
In my next article I will take you through this new hypothesis, and show you the major differences between how animal-based foods were traditionally eaten and the ways in which they are consumed today. Once you are familiar with these differences, it will be easy to see that these animal-based foods consumed today hardly resemble the ways in which they were traditionally consumed.
Most importantly, I’ll show you why it is counter-productive for vegans, omnivores, high fat or paleo folk, and any others to continue to argue whether or not animal-based food consumption causes disease. Rather, we need to change the argument to when they cause disease, and when they can be a component of a healthy diet. We need to shift the perspective on what a healthy omnivorous diet is, so that we can see that the differences between the (healthy) vegan diet and the (healthy) paleo diet really aren’t so big after all.
If one of our ancestors were to magically appear today, I would imagine that they would not recognize the animal-based foods we consume today. It doesn’t really matter which era you pick – whether it’s 2,000 years ago, or 200 years ago – the outcome would be the same. If given a glass of milk, they would be shocked to find that it tastes much more like water than the rich beverage they knew. If given a dish with chicken as the main feature, they would be concerned as to why there was a huge chunk of muscle in front of them. If given a typical American dish they would be confused as to how there could possibly be so much cheese covering a dish, when it was once used sparingly.
Most importantly, they would likely be outraged that all the nutrition had been taken out, leaving only whopping amounts of protein.
The point is that the meat consumed today is not really meat – not in the traditional sense. Same goes for dairy, and all other forms of animal-based foods. These are simply more industrial foods.
Consuming animals doesn’t kill us. Consuming industrial foods does. The link between animal consumption and disease is just another case of the power of industrial foods to wreak havoc on the human body. In my next article I’ll pick apart the evidence and show you why.
References
- Etemadi, A., Sinha, R., Ward, M. H., Graubard, B. I., Inoue-choi, M., Dawsey, S. M., & Abnet, C. C. (2017). Mortality from different causes associated with meat , heme iron , nitrates , and nitrites in the NIH-AARP Diet and Health Study : population based cohort study. http://doi.org/10.1136/bmj.j1957
- Arya, F., Egger, S., Colquhoun, D., Sullivan, D., Pal, S., & Egger, G. (2010). Differences in postprandial inflammatory responses to a “modern” v. traditional meat meal: a preliminary study. British Journal of Nutrition, 104(05), 724–728. http://doi.org/10.1017/S0007114510001042
- McKenzie, A. L., Hallberg, S. J., Creighton, B. C., Volk, B. M., Link, T. M., Abner, M. K., … Phinney, S. D. (2017). A Novel Intervention Including Individualized Nutritional Recommendations Reduces Hemoglobin A1c Level, Medication Use, and Weight in Type 2 Diabetes. JMIR Diabetes, 2(1), e5. http://doi.org/10.2196/diabetes.6981
- Ebbeling, C. B., Swain, J. F., Feldman, H. a, Wong, W. W., Hachey, D. L., Garcia-lago, E., & Ludwig, D. S. (2012). Effects of Dietary Composition During Weight Loss Maintenance: A Controlled Feeding Study. The Journal of the American Medical Association, 307(24), 2627–2634. http://doi.org/10.1001/jama.2012.6607.Effects
- Tang, W. H. W., Wang, Z., Kennedy, D. J., Wu, Y., Buffa, J. A., Agatisa-Boyle, B., … Hazen, S. L. (2015). Gut Microbiota-Dependent Trimethylamine N-Oxide (TMAO) Pathway Contributes to Both Development of Renal Insufficiency and Mortality Risk in Chronic Kidney Disease. Circulation Research, 116(3), 448–455. http://doi.org/10.1161/CIRCRESAHA.116.305360Tang, W. H. W., Wang, Z., Kennedy, D. J., Wu, Y., Buffa, J. A., Agatisa-Boyle, B., … Hazen, S. L. (2015). Gut Microbiota-Dependent Trimethylamine N-Oxide (TMAO) Pathway Contributes to Both Development of Renal Insufficiency and Mortality Risk in Chronic Kidney Disease. Circulation Research, 116(3), 448–455. http://doi.org/10.1161/CIRCRESAHA.116.305360
- Burgers, A. M. G., Biermasz, N. R., Schoones, J. W., Pereira, A. M., Renehan, A. G., Zwahlen, M., & Egger, M. (2017). Meta-Analysis and Dose-Response Metaregression: Circulating Insulin-Like Growth Factor I (IGF-I) and Mortality, 96(September 2011), 2912–2920. http://doi.org/10.1210/jc.2011-1377