Peter Attia

Obviously, I'm being facetious, but that's basically the way the discussion is sort of shaping out.

So I think with that said, we need to take a closer look at the data so that an individual who is in the 97% of the population who chooses not to be completely dogmatic and extreme can make a well-informed decision.

And frankly, that starts with me.

I actually care deeply about this topic on a personal level because I'm actually not sure how much fiber I should be eating.

Yes.

Apologies in advance to the veteran listener who's heard me talk about this at length.

I think it's always worth spending a moment on this because I also realize there are people that might be new to this.

So epidemiology, in particular nutritional epidemiology, tends to be heavily confounded by healthy user bias.

And that means that people who are doing one healthy thing, for example, like eating a high-fiber diet,

tend to be doing many other healthy things.

They might be exercising more, they're much less likely to smoke, they're probably getting more sleep.

And while a number of these things can be statistically modeled and corrected for in what is referred to as an adjusted analysis, it is essentially impossible to capture every one of these things and statistically correct for them.

In other words, you are very likely to be capturing other healthy habits when you're trying to simply measure one thing.

And of course, that's the hallmark of doing experiments.

The reason an experiment, particularly a randomized experiment,

and ideally a blinded randomized experiment as the gold standard is so important, is because it allows you to isolate one variable at a time.

And epidemiology does not allow you to do that.

I think the other reason that epidemiology is challenging here, and this is

again, not unique to epidemiology, this is a common phenomenon in all nutrition research, is it is difficult to disentangle the potential impacts of fiber itself from the potential impacts of things that traffic with fiber, the other micronutrients and phytochemicals specifically, because of course fiber is found in plants.

And plants are presumably known to contain many things that provide some benefit, and therefore it's difficult to disentangle them.