Mary Roach: A Day in the Life of Your Gut

A day in the life of the bacteria in your gut. They are on a different schedule from you because you're eating, and it's taking a certain amount of time for the bacteria to make their way. The bacteria are all in the large intestine, which is the end of the line. Well, the rectum is the end of the line. But this is a place where your body's kind of done with everything.

You've absorbed — in the small intestine, you've absorbed all the nutrients that you can that your body's going to use. And the stuff that they don't want, it's the kind of stuff that you throw into the compost. The large intestine — that's the composter. That's where the bacteria live, and they can use it. And they're like, "Oh, I'll take that."

So all your bacteria are down there, in your colon, and they're waiting for you to be done with what you're gonna do with it. And then it's passed along, so it's a certain amount of, you know, it's like five hours before you're sort of — it's making its way. And coincidentally — that's the peak in flatulence is about five hours after a meal when the bacteria are kind of doing their thing.

Because flatulence is gas produced by bacteria breaking down — it's usually sugars of some kind with lentils and beans being the most famous contributors. Anyway, so they are happily doing their thing. So they're on a lag from your schedule, so whenever you're eating, then you sort of wait a while, and then they're eating. And I don't know exactly what else they do with their lives in there.

I don't know how they pass the time in between. I don't know how much fighting is going on. I think it seems to be like a lot of gang tribe warfare going on because, you know, when you hear about a fecal bacteria, this is — if you were a gut bacteria and suddenly here comes this whole — it's this, you know, population — giant population of foreigners.

You know, it's like some crazy immigration situation where they're duking it out and the strongest ones win. So that's a whole global warfare scene going on. On a day-to-day life in the colon is probably pretty mundane. It's very centered around food, a little bit of, you know, reproduction.

Yeah, it's a simple life I think. Pleasant. Probably pleasant. The weather is great. It's very uniform. It's kind of like — kind of like the Bahamas in there. It's very — minus the tropical breezes, I guess. Oh no, a little bit of the breezes...