The Mighty Big Book of Stuff I Don't Know

My grandfather used to say*: “What I don’t know could fill a mighty big book.” And that’s true no matter who you are. Sure, you might know someone who “knows everything,” but they don’t actually. And, in fact, it might just be that they know a few things about something that you don’t. But we shouldn’t mistake casual trivia (or even in-depth knowledge about certain subjects) for blanket expertise. As far as we know, the human brain has a basically limitless capacity for learning, which is very cool, but even if you studied everything imaginable all day, every day, for the rest of your life, you would still be left in the same boat as my grandfather: knowing far less than what you DON’T know.

What does this have to do with longevity, health, and fitness? I think it’s important, as we all navigate this space, to understand who and what to listen to. There are a lot of people on social media, some with impressive credentials, who don’t say “I don’t know” enough. It’s not necessarily that they actually SAY it, but it’s how they deliver information. Do they cite their sources and do they cite them accurately? Do they speak in absolutes? (“Just do/don’t do this ONE thing and all your problems will be fixed!”) Do they give nuanced answers?

Generally speaking, the people I decide to pay attention to and follow are not only offering where their information comes from (i.e. which study), but they are also willing to discuss how the study might be limited. Science is incredible, but you can find studies that can be used to suggest almost anything. However, not all studies are equal in their rigor and the headline you might read about a certain study may be a gross oversimplification of what conclusions the study did or did not reach. Science also takes time and true scientists are not swayed by any one study. Instead, they gradually form or change their thinking based on the scientific consensus and the preponderance of evidence that that requires.

Also, as I’ve alluded to before, there are no silver bullets or magic pills. The human body is fabulously complex and the product of about a billion years of evolution, all the way from the basic building blocks of life, to single-celled organisms, to the first vertebrates, to apes, to us (with a few other steps along the way). And, like any complex thing, we know a lot, but there is still far more about the human body that we don’t understand.

For instance, we know comparatively less about human females than we do human males because the vast majority of studies only included males or were majority male. I don’t think you have to be an OBGYN to understand that there are differences between females and males, especially when it comes to hormones, but so much of the research has not included (or has not included enough) females. Even in the realm of seemingly basic, everyday stuff, like sleep or the perception of pain, an incredible amount of research has been done in just the last twenty years or so, and, again, there is still a lot that we do not understand.

Lastly, as I just mentioned, the human body, much like the world, much like humanity, is dizzyingly complex so I think it’s safe to be wary of anyone who says anything with absolute certainty. Even when it comes to seemingly simple questions, nuance becomes hard to avoid for someone who is being critical, honest, and rigorous. “Should I drink water?” Yes, absolutely, we need water for any number of our bodily functions and, to put it more bluntly, we need water to keep us from becoming un-alive. But, too much water in certain situations can be dangerous, even deadly. Just like too little water.

So, if someone asks, “How much water should I drink daily?” the answer should be more nuanced or we need to ask for more information. “How much water should you drink?” Well, that depends. What’s the temperature, humidity, and elevation? What activities are you doing? That answer is going to vary A LOT depending on whether you are relaxing indoors on a cool rainy day versus doing a 20-mile hike at elevation in the summer in the desert. Blanket, simple answers are attractive, but they aren’t necessarily helpful and, at times, they might even be dangerous.

In the end, I recommend looking for people who are willing to address the nuance in the world, who can discuss how and where they get their information, and who avoid speaking in absolutes and giving simple answers to complex questions. To that end, I think it’s important to let you know which figures in the health, wellness, and longevity space I turn to. The following people are not only experts in their field, but they are critical thinkers and they understand that the world is complicated and there are no (or at least very few!) absolutes, just a lot of nuance and context.

As Dr. Peter Attia, whose book, Outlive, started me on this journey, is fond of saying (though it’s not his quote): “The farther you are from shore, the deeper the water.” Which is to say that the more you learn about the human body or, indeed, anything, the more complex and confounding things get.

Let me know who you like to listen to in the comments below! And now, who I turn to (an incomplete list):

• Peter Attia, MD

• Andy Galpin, PhD

• Rhonda Patrick, PhD

• Layne Norton, PhD

• Mary Claire Haver, MD

• Brady Holmer, Phd

• Gabrielle Lyon, MD

• Michael Easter

*My dad’s dad died before I turned one so I never heard him say this, but my dad would say it.