I often describe myself as having an inclination to try and optimize things. I have observed in the past that I tend to bring this inclination to bear particularly on the unimportant stuff, which always seemed odd. But just this minute I have come to understand why: I do it this way to free up time to do the important stuff exactly the way I want, whether optimal or not.

Take reading, for example. There are all kinds of ways to optimize your reading—ways to read faster, ways to absorb more of what you read, ways to organize what you’re going to read, ways to keep track of what you have read, etc. I have no interest in any of those things, because reading is important. I want to do it exactly the way I want to do it.

Figuring out some trivial reordering of exactly how I put toothpaste on my toothbrush so that I can save 5 seconds a day is much more likely to be the sort of thing I’d do—because I don’t care. I have no interest in how I brush my teeth (as long as my teeth don’t fall out), but freeing up 5 seconds a day that I can spend doing what I want to do is motivating out of all proportion to the actual time savings.

(It’s actually not so disproportionate. It takes just 240 days saving 5 seconds per day to break even on spending 20 minutes figuring how how to save those seconds. Every 5 seconds after that is pure gravy.)

Anyway, since I mentioned recently that my optimization efforts tended not to have much payoff, in my post on getting better at life under late-stage capitalism, and having literally just now realized why that was, I though I should add that bit.

I have lost actual physical paper books many times over the years—loaned and never returned, accidentally left somewhere, dropped in the tub, left on a windowsill and rained on, literally worn out from re-reading. Many were lost when my house fell down. One was confiscated by a teacher. I’ve not yet lost an ebook.

Everybody knows that you come to be like the people you hang out with, and most people understand that you can take advantage of this to improve your life. If you want to be more productive, hang out with productive people. If you want to be an intellectual, hang out with intellectuals. If you want to be healthy, hang out with healthy people.

I rather suspect this last is something hardwired in our brains, probably explaining part of the stigma faced by people who are disabled or disfigured. Probably strongly selected for in circumstances where infectious disease is a major cause of mortality.

I have always assumed that this is primarily mediated by lifestyle, with the shift largely produced by adopting pieces of the lifestyles of the people you hang out with. Hanging out with people who read a lot normalizes reading a lot. Hanging out with runners normalizes taking up running.

It should have been obvious—maybe it is obvious to everybody else—but it only recently occurred to me that a large part of this may well be mediated by microbiomes.

Your microbiome will shift to converge with the microbiome of people you hang out with. (Of course, theirs will also shift to converge with yours.) If you share meals with someone, your intestinal microbiome with shift toward theirs—probably more so and more quickly if you share a kitchen, utensils, or food prep tasks, and probably more so yet if you share a bathroom. If you share a touch with someone, your skin microbiome will shift—again, more so and more quickly if you share a bed with them.

Actually, an anecdote on this last: When I met Jackie she had a fungal infection of the skin that she’d picked up in India, and that had persisted for years. She treated it with tolnaftate, which worked adequately to knock it down when it became annoying, but had not cleared it up, either in India or after she came home. However, a few years after we got married I noticed that it seemed to be gone. With no evidence whatsoever, I’m inclined to take credit for this, figuring that my skin microbiome contributed useful organisms that her skin microbiome integrated in a way that eventually let it displace the fungal organisms.

So far, all the efforts to find an “optimal” microbiome have foundered, probably because the problem is intractably complex, being inextricably connected with the genes of the host, multi-generational epigenetic history, the immune system (and its lifetime history of chemical and biological insults), along with all the obvious factors—what organisms initially seeded the microbiome, history of antibiotic use, diet, etc.

Because of that, I’m much less interested now in interventions such as probiotics. More and more I’m inclined to prefer what used to be pretty obvious: Trust your immune system to cultivate a healthy microbiome (and hang out with healthy people to give it a little extra to work with).