Why nutrition research is flawed
If you're like most people, you probably get dizzy with how quickly science seems to change. One day coffee is bad for you, the next day it is good, a week later it's bad again. The reason the nutritional science seems to change so quickly is because people are using the data incorrectly. The vast majority of nutritional research is a type of research called epidemiological research. Epidemiological research is a type of research that identifies relationships between variables, but can't be used to come to conclusions on what causes what. What this means is that the conclusions in epidemiological research can be used to say that there is a relationship between A and B, but it can't say that A causes B or B causes A. This is because this type of research doesn't do a good job of controlling for other variables, called confounders, that could impact the results. So while A and B may have a relationship between one another, there could be a third variable C that is also related to A and B that is actually driving the change.Let's look at an example. Many people have heard how healthy whole grains are, and it comes from this very type of research. However, there are a number of confounders that these studies fail to control. Certainly diet isn't the only factor in how healthy you are. Physical activity, not smoking, managing stress, and getting quality sleep all have an impact on health, and these studies don't control for these things. Since we've been told, prematurely must add, that grains are a part of a healthy diet, people who are interested in health would tend to flock towards them. Healthy people also tend to exercise, get quality sleep, limit alcohol consumption, and avoid smoking.
Also, in an attempt to torture the data until it tells them what they want to hear, researchers often perform statistical analyses to tease out these confounders so that they can come to conclusions. However, if I wanted to "tease out" what percentage of a dead person's coronary blockage was from a lack of physical activity and which percentage was from smoking, I couldn't do that reliably. Even if I cut them open and looked directly at their blockage, I couldn't tell what percentage came from which poor lifestyle decision. So how certain are we that the mathematical models these scientists use are valid?
This isn't to say that this data is useless, the point of epidemiological research is to help generate hypotheses for stronger research that does control confounders. The problem is, that's not how it gets reported, and the popular press often draws conclusions from research that can't be used to draw definitive conclusions. Another problem is that research is expensive and the only way you could run a proper experiment and draw conclusions from it would be to take a group of people, lock them in a metabolic ward for 3-6 months, and control every aspect of their life. Very few people would be willing to do that. Even then, what if the poor health outcomes take years to develop?
Why an evolutionary approach is necessary
An evolutionary approach to health and wellness is better than just using epidemiological data for a couple of reasons. First and foremost, it starts the discussion closer to the beginning. As much as it pains people to hear, nutrition research didn't start 100 years ago. Long before we were filling out questionnaires on what foods we were eating and measuring how healthy we were, traditional cultures were observing how food affected their people over the course of thousands of years.For example, most traditional cultures prepared grains and legumes by first soaking them for 24-48 hours. They obviously did this for a reason, if these foods were health promoting in their natural form why make all of the extra work? When we look at what this process does, it makes sense. These foods contain anti-nutrients that bind minerals found in them and make them unable to be absorbed from the intestine. Soaking them removes some of these anti-nutrients. If your goal is survival in an environment where food is scarce and you need to expend a lot of energy to get it, it doesn't make sense to gather food that isn't going to give you what you need to survive.
What is even more astonishing about this process is that these people didn't even know what minerals were, they just knew the outcome of eating these foods in different forms and chose the best option. So why did we stop doing this? For some reason we chose to ignore thousands of years of observational experience just because there wasn't a randomized clinical trial showing it's effectiveness. However, there was never a randomized clinical trial showing bread to be healthy to eat, but it is a large part of most people's diet regardless.
Another reason an evolutionary approach to health is beneficial is that it gives you another tool in your tool chest. Just because you choose to look at things from an evolutionary perspective doesn't mean you can't also look at it from a different perspective as well. In fact, you should look at health from as many perspectives as possible to come to your conclusions. You should use the nutritional sciences, biological/evolutionary sciences, physical sciences, and any other science that you can. Any time you can use multiple areas of research to formulate a conclusion you should.
Finally, an evolutionary approach to health is effective because evolution is the guiding tenet of biology, the science of life. Every science dealing with health is based on biology. Since biological functions are driven by evolution by natural selection, most decisions within biology should take evolution in to account. This includes health, weight loss, and anything you imagine any human does on a day to day basis. Not using evolution to help guide health is like being a pilot and flying a plane without using the principles of flight.
We know that the environment has shaped who we are, and looking at how that environment has changed and how we interact differently with our environment can give us many clues as to what is the best environment (Food-wise, activity-wise, environmental condition-wise, etc.) for optimal health. We know processed foods were not the norm. We know regular physical activity throughout the day was the norm. We know regular light and dark cycles coinciding with being awake during the day and asleep during the night were the norm. We know that none of these things appear to be the norm for most people today.
As you look at research in all of these fields, there is nothing but support for the way our environment shapes who we are and contributes to our overall health. We know shift-workers and people who don't sleep well tend to be prone to Type 2 diabetes. We know sitting all day long leads to a host of health problems. In many ways we have found workarounds that may or may not be suitable. We know Vitamin D3 is vital to our physiology, so people often take D3 supplements. Whether or not this is a suitable replacement for getting D3 directly from the Sun is something we don't know, so why not try to approximate the conditions by which we seem to be engineered to get Vitamin D3? Is it that difficult to get out in to the sun for 30-40 minutes a day? In certain climates, D3 is unavailable from the Sun during certain times of the year so there is likely a benefit to supplementing during these times.
Conclusion
Using many perspectives to guide lifestyle, including an evolutionary one, is a winning strategy. Using as much of the science that is available will help narrow down conflicting data and drive you in the right direction where data is not available. This is one of the primary failings in nutritional research, no college level programs incorporate these principles in their coursework. There are many logical fallacies that people make when they take a narrow approach to health. On one end, many people who only use an evolutionary perspective make a naturalistic fallacy that all things natural and in their normal form are healthy. There are many natural things that are unhealthy, many poisonous mushrooms, berries, and plants that will kill us if we eat them. Just because something is in it's natural form doesn't mean it is a healthy choice.On the other end you have what I call the legacy fallacy, since we've always done it that way it's fine to do it that way. An example of this is people who defend the consumption of a food product just because we have been consuming it regularly during our recent past. Unless there are well controlled clinical trials showing it to be healthy, we have no idea whether something is healthy or not. It also works both ways, just because we haven't consumed a food doesn't mean we can't consume that food or that consuming it is unhealthy. Looking at things from multiple perspectives will help you avoid these fallacies and drive you to better health decisions.