Diet is a difficult subject. Whether it’s the vegan diet, vegetarian diet, pescatarian diet, ketogenic diet, carnivore diet, or innumerable other diets focused on the inclusion or exclusion of certain foods, there’s no lack of dietary frameworks to make sense of and experiment with. There’s also no lack of zealots who advocate that their diet is the best diet, because they experienced benefit from the diet, and therefore everyone will experience the same benefit. And, if the overwhelming number of options out there and endless enthusiasm of the diet zealots isn’t enough to make your head spin, then surely the constant stream of flashy headlines in the media will, each making bold claims about a particular diet that, considered in aggregate, all seem to contradict each other.
Why is this so complicated? Aren’t there studies that indicate what the best diet is for humans, that we could all agree on, and that could put all of this nonsense to rest?
The short answer: yes and no.
The long answer is that there are hundreds of thousands of studies that have shown that certain diets have a positive effect on our health, while others have a negative effect, but many, if not most, of these studies have to be discounted due to the unfortunate reality that nutritional epidemiology—the study of nutrition in relation to human health—is fraught with issues.
To understand how we got here, and why nutrition research is unlikely to provide answers, let’s consider four major issues of nutritional epidemiology that stand in the way of progress.
Industry funding
Studying the long-term effects of a particular diet on a population requires significant funding, and most of this funding comes from the food industry, which leads to an obvious, though underreported, conflict of interest. Given this bias, it’s no surprise that unfavorable results, or results inconsistent with the interests of the companies paying for the studies, tend not to be published, and that favorable results are often found to be arrived at via flawed methodology.1
Flawed methodology
The standard methodology for studying the effectiveness of supplements, medication, and other interventions is the randomized controlled trial—a form of study design in which participants are randomly assigned to an experimental group or a control group, to reduce the potential for confounding factors—but the vast majority of nutrition research is not randomized, and instead observational, which limits the significance of any conclusions arrived at.2
In observational studies, participants are asked to report either what they ate, or the degree to which they adhered to a particular diet being studied, over a certain time period. Such studies are thus completely reliant on accurate reporting by participants, despite the high likelihood for inaccurate reporting, or recall bias, in which participants aren’t able to remember, say, exactly how many ounces of broccoli they ate last month.
Slow iteration
Establishing a causal relationship between a particular diet and the health of a population requires studies to be conducted over years, or even decades. Whereas the effects of a supplement or medication can often be identified in months, the effects of a diet, positive or negative, almost always require more time to manifest.
In most cases, the significance of findings from nutrition studies, if any, is proportional to their duration, wherein the findings from shorter studies are less significant and those from longer studies are more significant. This results, of course, in less opportunity for testing hypotheses, iterating, and retesting, relative to other fields, which ultimately results in nutritional epidemiology advancing slowly, when other fields of research, uninhibited by study duration, are advancing quickly.
Media misrepresentation
In the rare cases in which studies are able to demonstrate associations between a certain diet and the health of study participants, the media often misrepresent the findings, translating associations into clickbait headlines that declare unequivocal causal relationships.
Clearly, correlation doesn’t equal causation, but that’s not what the headlines will have you believe. Writers of such hogwash will, for example, take a nonrandomized, observational study of insignificant sample size that identified a weak association between the consumption of coconut oil and increased risk for cardiovascular disease, and translate the association into a vilification of coconut oil, neglecting to mention that all of the study participants were overweight, diabetic, and, other than the coconut oil, ate the standard American diet.
How to think about what to eat
If most nutrition research is flawed, due to industry funding that results in bias, flawed methodology that invalidates findings, slow iteration that inhibits progress, and media misrepresentation that translates weak associations into causal relationships, then how do we determine what to eat? What can we rely on to inform the best diet for human health, if nutritional epidemiology isn’t going to be much help?
I think the best approach, in the absence of definitive answers, is to look to the past and consider what our hunter-gatherer ancestors ate.
If we assume the anatomically modern human to date back 200,000 years, then for 99.9% of human history—up until the Industrial Revolution, around 200 years ago—we ate a diet primarily consisting of fruits, vegetables, nuts, seeds, meat, and fish. Everything we consumed was natural and unadulterated. Chronic illness was unheard of.
But the introduction of modern agriculture and food manufacturing changed everything. While such technological advancements enabled us to spend less time worrying about our next meal, they also introduced certain foods, such as grains and, ultimately, processed foods, that our genes and biology hadn’t adapted to over thousands of generations as hunter-gatherers. The nutrient density of our diets, in the United States, quickly declined, and, along with it, the health of most Americans, an alarming 60% of whom today have a chronic illness.3
Despite how complicated diet may seem, given how many options there are, and how much contradictory information there is, I propose that it doesn’t have to be so complicated. That the problem is that most Americans are eating a diet incompatible with human health, and thus the solution is to bring our diet back into alignment with the genes and biology of our hunter-gatherer ancestors, because that’s still who we are.
We’re no longer in caves, and we no longer need to hunt and gather to get our food. But our genes and biology haven’t changed. So our diet shouldn’t either.
If you’re interested in making the transition to the ancestral diet, and need support as you eliminate certain foods from your diet that could be compromising your health, you can schedule a call to learn more about Quantify membership and how we can help you to resolve your symptoms and optimize your health.