Paleo-tourist puts a bug up his ass. John Hawks calls BS.

From Hawks:

Jeff Leach, at the “Human Food Project”, has written pungently about a bout of microbiome self-experimentation: “(Re)Becoming Human: what happened the day I replaced 99% of the genes in my body with that of a hunter-gatherer”.

AS THE SUN set over Lake Eyasi in Tanzania, nearly thirty minutes had passed since I had inserted a turkey baster into my bum and injected the feces of a Hadza man – a member of one of the last remaining hunter-gatherers tribes in the world – into the nether regions of my distal colon. I struggled to keep my legs in the air with my toes pointing towards what I thought was the faint outline of the Southern Cross rising in the evening sky. With my hands under my hips – and butt perched against a large rock for support – I peddled an imaginary upside down bicycle in the air to pass the time as I struggled to make sure my new gut ecosystem stayed put inside me.

I have to say, this is just wrong.… There seems to be a lot of quackery here — almost a New Age belief in the power of a guy unspoiled by burgers and fries.

“Just wrong” is dead right. Call it colonialist colonic tourism. As Hawks notes,

The Hadza have their own long evolutionary history. Their diet is merely one representative of the marked dietary diversity of recent hunter-gatherers. Other foraging groups, for example, the Ache of Paraguay, have a very different dietary composition. The study of these microbiomes is scientifically very interesting, and we may discover commonalities among them. But the idea that the microbiome of any Hadza person represents an “ancestral” or “healthy” human population is nonsense. They have their own distinctive set of challenges affecting their microbiomes, including the aforementioned parasites. A microbial community that has formed within a Hadza gut might work equally well anywhere else, but there’s really no reason to expect that it will.

Also, as Ed Yong describes here in Nature, microbes in hosts with different genetic backgrounds (as in, two different people of different cultures, environments, and dietary legacies) can have very different effects. Some strains of a bug called H. pylori, for example, are “more likely to cause tumors when they did not co-evolve with their hosts.”

In other words, this stuff is complicated. Mr. Leach seems to think it’s simple, and that he can pick up paleo power as readily as one can put on a fedora to go noir.

I suppose Mr. Leach might answer that it’s his body, so he’s free to subject himself to such experimentation. Which he is. But his gleeful presentation of this stunt as sensible experiment, eco-adventure tourism, and a sort of wonderful carefree lark is irresponsible — to say nothing of the revolting and mindless colonialist aspects of him reducing the Hazda culture to a source of stool. The layers of yuck here are deep enough to drown in.

Are we at peak paleo yet? Lord I hope so.


  • An exotic intestinal infusion, at (the must-read) John Hawks Weblog.
  • Human-microbe mismatch boosts risk of stomach cancer, by Ed Yong at Nature.



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