On The Menu Today: Prehistoric Poop and Jerusalem Artichokes


One reason our ancestors may have eaten more healthily than we do.
Nope. There’s no way around this.

In writing about dietary fiber, once again I’ve inevitably got to talk about, um, number twos.

In doing so, though, I follow in illustrious footsteps.

In fact, way back in 430 BC the celebrated ancient Greek physician Hippocrates was writing about the laxative effects of coarse wheat in comparison with refined wheat.

It seems he was an early fan of roughage.

A couple of millennia later, John Harvey Kellogg, physician, co-inventor of corn flakes, and the holder of some pretty extreme views about sexual abstinence (don’t ask) published widely on the virtues of bran.

He claimed consuming it increased stool weight, eased bowel movements, and prevented disease.

Bran, by the way, is the outer hard layer of any cereal grain, so Hippocrates’ coarse wheat would certainly have contained a modicum of bran.

Of course neither of these gentlemen knew of dietary fiber’s role in feeding the bacteria that we now know reside in our guts, as well as in and on our bodies.

It was only in the mid-1990s that dietary fiber was classified as a prebiotic.

“Biotic” comes from the Greek word “bios”, meaning life, by the way, which when you stop to think about it makes the literal meaning of antibiotic rather unfriendly.

Anyway, prebiotic means “before life”, referring to bacteria, and specifically prebiotics are “nondigestible food ingredients that beneficially affect the host by selectively stimulating the growth and/or activity of bacteria in the colon, thus improving host health.”

Yup, in more ways than one, that’s a bit of a mouthful.

The important thing to understand is that dietary fiber is important. But most of us get far too little.

Although the recommended daily amount of fiber in the US is 25 grams, Americans typically only consume half this amount (about 15 grams a day).

Broadly you’ll boost your fiber intake by adding whole grains, vegetables, fruits, and legumes to your diet.

However prebiotics don’t all deliver equally.

By broad consensus, about 6 grams of your daily fiber consumption should come from prebiotics, and to get this you could eat just 9.3 grams (0.33 oz) of raw chicory root, or 19 grams (0.67 oz) of raw Jerusalem artichoke.

At the opposite end of the scale, your 6 grams of prebiotics could come from a whopping 600 grams (1.3 lbs) of raw banana.

That’s roughly five whole bananas.

Chicory root’s prodigious prebiotic performance is principally due to the presence of inulin.

Inulins are naturally-occurring polysaccharides (long-chain carbohydrate molecules) that are used by some plants as a way of storing energy.

There’s nothing new about consuming inulin, though, as we know that at least some of our prehistoric ancestors got more than their fair share.

What evidence is there for this?

Well, archaeologists working in the northern Chihuahuan Desert have found well-preserved coprolites in caves.


Literally, “dung stones”.

Fossilized feces.

Petrified poop.

And analysis of these little beauties suggests that a typical male hunter-gatherer got around 135 grams of inulin a day, mainly from desert plants rich in the substance.

Good thing they didn’t have to rely on bananas, of course.

To get 135 grams of inulin they’d have needed to eat around 110 bananas a day.

Which is, indeed, a bunch.

Have a great week!

Further reading

Fiber and Prebiotics: Mechanisms and Health Benefits

John Harvey Kellogg