How to Think Critically



Should you eat paleo or vegan? Should you do crossfit or bodybuilding? Is wine good or bad for your heart? We are bombarded by varying perspectives on a variety of topics on a daily basis. You need to sort out what’s real and what’s nonsense. I’ll show you how to do exactly that.

Many of our beliefs are plain wrong and not based in science or fact but rather in anecdotes, word of mouth, or misinformation from seemingly trusted sources. It’s important to understand that many of our beliefs are socially constructed. As humans, we are incredibly malleable in what we believe and how we perceive the world; the influence of others holds tremendous weight. Homo sapiens have evolved since our hunter gatherer times to follow the herd because falling out of line could lead to being ostracized, which would ultimately mean end of the road for one’s reproductive fitness.

However, this desire to fit in and the resultant homogenization of our perspectives often does more harm than good in our current age. Throw in the power of clicks, money, and advertising with companies fighting for our attention, and it’s no surprise that its incredibly tough to determine fact from fiction. In order to sift through all the noise and hyperbolic sensationalism and figure out the truth, we must question our own beliefs and values to ensure that we have deliberately chosen them and not simply blindly believed what we have been told.

Let’s start with the pinnacle of progress and understanding: scientific research.



Many of us turn to the most recent journal articles to help guide our beliefs and ways of living. However, understanding research requires a nuanced understanding of not only the study design, but also subject matter, funding, and limitations. One of the best ways to witness the importance of these factors is by turning to nutrition science, which still remains highly controversial. One week it sounds like paleo is the best, the next week vegan, and the week after that Mediterranean.

In 2014, Bazzano et al published a randomized trial comparing low-carb to low-fat diets. Many interpreted the findings as a landslide victory proving that a low carb diet is superior. The low-carb diet, after all, showed an increase in HDL, which is your good cholesterol, and greater weight loss.

This was a randomized trial, so it must good study, right? It is true that randomized prospective trials are better than retrospective trials, which analyze data from the past and look for correlations. However, by understanding the subject material and limitations, it becomes apparent that like many nutritional studies, this one is far from perfect. The study relied on self-reported dietary information which is prone to recall bias, dietitians were not blinded, there were no cardiovascular disease endpoints, the low-fat diet was really just a regular-fat diet, and fiber intake was less than half of the recommended amount. Additionally, HDL, your good cholesterol, functions to transport cholesterol from the periphery to the liver. Increasing the amount of fats and cholesterol you eat will require a greater amount of HDL. If you have more garbage, you need more garbage trucks.

It’s equally important to pay attention to who funds the study. Data, but even more so common sense, indicates that industry funding is associated with pro-industry conclusions. The Vox recently came out with an excellent article explaining how the chocolate industry has funded hundreds of studies that promote chocolate as a health food. Is chocolate actually good for your health when unbiased studies are examined? The take away is no, but cocoa-based products with little or no added sugar or fat seem beneficial. For those of you who want a more scientific analysis, check out the systematic review by Hooper et al that essentially said the same thing.



Now let’s be real, none of us goes to the primary literature for everything. Nor should we. Your beliefs don’t ALL require scientific backing, but they do all require a healthy dose of skepticism.

If I asked you how much water you should drink in a day, you may suggest 8 glasses. The 8 glasses of water recommendation actually has minimal scientific basis, and can be traced back to a 1921 paper where the author measured his own urine and sweat to determine that he lost approximately 3% of his body weight in water per day, which is approximately 8 cups. I’m not sure about you, but basing humanity’s water intake recommendation off the results of one man seems misled.

Your belief of whether or not there is a god is definitely not based on scientific fact. People have varying opinions and it’s critical to be aware that just because you do or do not believe in one thing doesn’t mean that another persons opinion isn’t valid. This is especially important when your beliefs aren’t easily proven one way or another, such as with regards to religion.



To sift through the misinformation, it is essential to practice critical thinking. What is critical thinking? It’s essentially the skill of absorbing important information and using that to form a decision or opinion of your own, rather than just reciting what you hear others say.

1) Determine what’s important

Not all things require this level of analysis. When deciding which movie to watch tonight, maybe you don’t have to be 100% certain on which movie would be best for your current mood and time allocation. So first, determine what is important for you to understand on a deeper level. To start, any behavior you are changing that significantly effects your health, life, or well-being on should require a deeper understanding where you have practiced critical thinking. As a doctor, I would argue that anything effecting your health, like deciding on which diet or exercise to pursue, requires critical thinking and analysis.

2) Pay attention to the right details

In this day and age, we are exposed to an all time high of information. Determining which facts are relevant and which are irrelevant will serve you well. First, question the source. Sources are not always reliable, as we have already gone over. Thinking about who benefits from a statement can also help you shift your perspective and view the topic in a more objective way.

3) Challenge the argument

The best way to challenge the argument is by asking the right questions. What is the counter-argument? No argument is bullet proof, and it’s your duty to question what you are told, to see the other side, to understand both sides of the coin.

4) Be wary of confirmation bias

Rather than question our beliefs, its human nature that we want to reinforce our currents views. You may find yourself reading articles that align with your beliefs, but why not learn about the opposing viewpoint? Understanding both sides will not only guide you closer to the truth, but you also will have a stronger backing and argument supporting your decision. If you find yourself repulsed by a certain point of view in an argument, chances are you are being closed minded and not objective. Take a step back, acknowledge your bias, and reapproach the situation with curiosity rather than your own agenda.


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