This is scientific American's 60 second science. I'm Christopher Intalyata. Got a minute?

You are what you eat, the old expression goes, but it leaves out one crucial detail.

We don't dine alone.

We dine with trillions of friends.

Jeff Gordon, a microbiologist at Washington University in St. Louis.

And they are partners in consuming these meals and processing these ingredients.

Those friends, they're microbes in our guts.

They break down dinner, including otherwise indigestible stuff, and pass the leftovers on to

more microbes, creating a complex food web inside us.

But that microbial garden is a lot more diverse in people who eat a calorie restricted

veggie-rich diet. The typical American diet on the other hand, breads, meat,

cheese, not a lot of veggies. It doesn't raise up near as diverse a crop of microbes.

And microbial diversity matters because in a mouse model,

Gordon's team found that if you give up the American diet in favor of a healthier one with lots of veggies,

the Americanized gut bacteria, being less diverse, aren't prime to respond.

They're not great at regrouping to accommodate all the nutrients and kale and broccoli and so on.

The studies in the journal Cell Host and Microbe.

Now all this isn't to say you shouldn't try to eat healthier because it's not clear how this microbial

efficiency translates into human health or to what extent you might be able to

pick up beneficial microbes from those around you as they demonstrated mice can in this study. But Gordon's

colleague Nick Griffin had this prediction. It's entirely possible that in the future

we will more and more recognize a need to reinstall absent populations of

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