Every day, we are bombarded with information about diet and health through newspapers, magazines, and the internet. Often, what you read one place conflicts with what another source tells you to be true. For example, one article may claim that you should make red meat a regular part of your diet, while another highlights the results from a recent study which seemingly show that eating red meat will increase your risk of developing colon cancer. Combine all of this with the fact that the views and opinions of various “diet experts” often differ markedly, and you can quickly understand why people are so confused about what to eat.
How can we separate the good advice from the bad and make our way through the maze of diet information?
A lot of people would say that the first step in the process that goes into finding information about diet and health is to look for randomized controlled-trials (RCTs), meta-analyses, and systematic reviews on the subject you’re interested in. After all, these types of studies are considered the gold standard of nutritional science. However, although RCTs and comprehensive reviews are absolutely invaluable when digging into nutrition and health topics, the problem with initiating the search for answers this way is it can often lead us astray.
One of the primary reasons there’s so much confusion and debate about nutrition is that there are a thousand different ways to look at the science/literature. Someone who’s drawn to the vegetarian movement will quickly focus on the studies that seem to support his cause, while those who favor a very low carb diet will point out the dozens of trials that seemingly support their ideas.
Even someone with no apparent preconceived notions can quickly be led astray and come to the wrong conclusions by looking at the research. Let’s take a topic like saturated fat for example. On the one side, there are plenty of seemingly good studies showing that a diet high in saturated fat can trigger low-grade chronic inflammation, while on the flip side there are also several reports indicating that saturated fat consumption is not linked with higher risk of atherosclerosis, heart disease, and all the other conditions butter and lard have been blamed for (1).
The reasons for these conflicting results usually boil down to differences in study design and methods, and it can often be difficult to separate what is good and bad research. Without a guiding framework to help us make sense of things, we’re grasping in the dark.
So, what is this guide we need to make sense of nutritional science? Evolution, of course!
Expanding our perspective
By looking at how we’ve eaten for millions of years, how our bodies have evolved, and how nutrition transitions have impacted human health, we establish the foundation we need to design a healthy diet in the 21st century. It’s not always easy to decipher our evolutionary history in such a way that we can draw concrete conclusions, but even by just getting a fraction of the answers we are looking for, we can begin to make sense of why things are like they are. With this evolutionary perspective in mind, we suddenly have a base to build our ideas upon.
Darwin didn’t focus much on nutrition and exercise, but he unknowingly gave us many of the tools we need to be healthy and fit in his book “On the Origins of Species”. By combining his ideas on evolution and natural selection with the science on gene expression/epigenetics and the human microbiome, it’s usually possible to predict what nutrition studies will show even before they have been done. That doesn’t mean doing and reading research is a waste of time – of course not, but because the evolutionary template is the foundation that supports everything else, having a basic understanding of evolutionary biology is far more powerful than any RCT or comprehensive review will ever be.
We have to realise that we are evolved creatures that were shaped by the forces of natural selection over eons of time. Just like our brain, gut, and musculoskeletal system were sculpted through millions of years of evolution, so were our nutritional needs. In other words, our nutritional needs are genetically determined (2, 3, 4).
Unlike what you may have been led to believe from reading recent newspaper articles on saturated fat or following the latest diet trends, what constitutes a healthy diet doesn’t change from week to week or month to month. Our genetic make-up is still largely the same as that of our Stone Age ancestors – and has certainly changed very little over the last couple of centuries (5, 6). Hence, our nutritional needs also remain fairly identical.
Combining the evolutionary template with modern nutritional research
It’s important to note that we didn’t evolve to be healthy, but rather to survive and reproduce under various, challenging conditions. In other words, looking back at how our ancestors ate doesn’t necessarily provide us with a clear-cut answer as to exactly how we should eat to achieve optimal health.
However, applying an evolutionary perspective to the study of nutrition is extremely important, as it allows us to establish a framework that we can use to make sense of modern nutritional science, and perhaps more importantly, it helps us figure out what type of diet Homo sapiens sapiens is well adapted to eat. Ultimately, by looking at nutrition through the lens of evolution we gain invaluable insights and tools that we can use to design a healthy diet in the 21st century.
The dietary changes that began with the Agricultural Revolution – and even more so with the Industrial Revolution – are extremely recent on an evolutionary time scale (10.000 years is just a blink of an eye from an evolutionary perspective). Certain genetic adaptations, such as increased frequency of lactase persistent alleles and alterations of the gut microbiome, have allowed us to tolerate more “Neolithic foods”; but we are clearly not well adapted to eat a lot of the foods that now make up the foundation of the diet in contemporary societies.
As I’ve outlined on the main diet page of this blog, as well as in dozens of other articles, a Paleo-style diet has solid scientific support and is the diet that is best matched with our genetic make-up. Hunter-gatherer diets sustained the human race for 2.5 million years, and hence, statements such as “The Paleo Diet is a fad diet” just comes off as ridiculous.
That doesn’t mean you have to eat a strict Paleo diet to be healthy, that other nutrient-dense, traditional diets aren’t a viable option, or that we shouldn’t debate the smaller stuff, such as whether or not fermented dairy products are healthy or if you should eat dark chocolate and legumes. However, we always have to stay within the bounds of the evolutionary framework. We can’t suddenly make claims that go against what millions of years of evolution tell us to be true.
The next time you come across information about nutrition in your favorite newspaper or read an online article highlighting the results from a recent study on saturated fat, protein intake or any other diet-related topic, ask yourself this question: Are the statements/results/opinions supported by the evolutionary evidence? If not, you’re probably best off moving on and getting your diet information elsewhere.